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How Much Material, What It Costs You, and What You Charge

Every calculator on the internet stops at "you need 16 yards." This one keeps going: your yard price, your waste, your markup, and the margin you actually keep. Eleven materials, all the arithmetic on screen.

STEP 1

Pick the material and put your measurements in

One mode at a time. Each asks for the measurements that material is actually sold against.

Measurements are in feet unless the box says inches. Depths and thicknesses are always in inches because that is how everybody says them on site.
4 in residential, 5–6 in for trucks
10% is the default because subgrade is never as flat as you think and a truck that runs short leaves a cold joint. Trenches over-dig, so use 12–15% on footings.
Under this, most plants add a fee
Reinforcement
STEP 2

What you need

Quantities in the units your supplier actually sells, with the arithmetic underneath so you can check it.

The math, line by line
STEP 3

What it costs you, and what you charge

Prices load as placeholders. Overwrite them with what your yard actually charges and tick the save box below so you never type them twice.

ItemQuantityUnitYour costTotal
Leave at 0 if you buy tax-exempt for resale
What you add on top of cost
The tool works out the markup that gets you there
$0.00
Your total material cost
$0.00
What you charge for material
$0.00
Gross profit on material
0.0%
Margin, not markup
STEP 4

The whole job

Add every material to one list and see the total cost, the total price and the blended margin across all of it.

$0.00
Total material cost
$0.00
Total material price
$0.00
Gross profit
0.0%
Blended margin
Nothing on the list yet. Work out a material above and hit "Add to the job."

Nothing you type is sent anywhere and no analytics event ever carries a number from this page. Estimates for planning, not tax or legal advice. Always check quantities against your own measurements before you order.

How much material do you need, and what should you charge for it? Quantity is geometry. Work out the area or the volume, convert it into the unit your supplier sells, and add a waste factor. Price is a second step, and it is the one nobody's calculator does: your cost per unit times the quantity, then your markup on top.

Worked out on a real slab. A 20 ft × 60 ft pad at 4 inches is 1,200 sq ft × 0.3333 ft = 400 cu ft, ÷ 27 = 14.81 cubic yards, and 16.30 yards once you add 10% for waste — ordered as 16.50, because plants bill in quarter yards. At $175 a yard that is $2,887.50 of concrete. Add 25% markup and you charge $3,609.38 and keep $721.88 — which is a 20.0% margin, not a 25% one. If you want to actually keep 25%, the markup has to be 33.3%.

Why does knowing the quantity not tell you what to charge?

Because quantity is the easy half.

Every big-box retailer will tell you how much mulch fits in a bed. They are good at it, they are free, and they are accurate, because the arithmetic has not changed since anybody was doing it. What they will never tell you is what those yards cost you at your yard, what you should put on the estimate, and how much of that is still yours after the truck is unloaded. They are not hiding it. It is just not their job. Their job is to fill a cart.

So the average small contractor ends up doing this in three places. Quantity on a retailer's website. Prices in a text thread with the guy at the supply house. Markup somewhere between a calculator app and a gut feeling in the truck. Then it gets copied onto an estimate, and by the time the material shows up nobody can reconstruct where the number came from or whether it still holds.

That is where the money leaks, and it leaks in four specific ways.

  • Waste gets forgotten. You order 14.8 yards for a slab that needs 16.3, the truck runs short, and now you either pay for a second short load with its own fee or you live with a cold joint in a driveway you warrant.
  • You quote in the wrong unit. The quarry sells stone by the ton and you measured in yards. Off by a factor of 1.4, on a 40-yard driveway, is a $700 mistake in whichever direction hurts.
  • Markup gets confused with margin. A contractor on r/Contractor put it plainly in June 2026: "I kept underpricing jobs for 2 years until I learned the difference between markup and margin. I was quoting jobs at '30% profit' and wondering why I was barely breaking even. Turns out I was confusing markup with margin. A 30% markup is only a 23% margin. On a $10k job that's $700 you're leaving on the table. Every. Single. Job."
  • Old prices get reused. Lumber, concrete and shingle prices have all moved in the last two years, and an estimate built off last spring's number is a discount you did not agree to give.

None of that is a hard problem. It is a bookkeeping problem that nobody has bothered to put on one screen for a two-truck operation, because the companies that could have done it sell $200-a-month software to people who bid off plan sets.

What does takeoff software actually cost in 2026?

Prices as of August 2026, taken from vendor pricing pages and from contractors who published what they were quoted. Anything with a tilde in front of it is a reported figure rather than a published rate card, and the whole category moves, so check before you sign.

What you could usePrice (Aug 2026)What it does better than this pageThe catch
Takeoff packages generally$200–$500 per monthScale quantities straight off a PDF drawing, count fixtures and symbols with a click, keep an assembly library so a wall type carries its own studs, board and screwsOnly pays for itself if you bid off plan sets. A GC on r/Construction: "I spend more time on calculating labor and material costs because I have to manually search for and get quotes from suppliers." The plan reader was never the slow bit.
Planswift~$1,200 a yearLong-established plan takeoff with assemblies and Excel export. Deep, and people who know it are fast in it.Per seat, Windows, and a real learning curve. Nobody masters it in a week between jobs.
Buildertrend$800/mo paid annuallyRuns the whole business: scheduling, selections, client portal, budgets, purchase orders against the estimateA contractor on r/Construction: "It's wild how the industry hides pricing just to sell a bloated $1,000/month database that forces you to change how your whole business operates. For a lean team doing $4M, those massive setups are totally out of touch with reality."
Procore$500/mo for the project management module, financials another $300–$500Genuinely good at multi-party commercial jobs with submittals, RFIs and drawing revisionsBuilt for the GC side of a job this size or bigger. Priced accordingly.
Jobber Grow$199/moQuotes, scheduling, invoicing and automatic quote follow-up, all tied to a customer recordIt is not a takeoff. You still type the quantity in yourself. From r/lawncare: "Jobber is great but the pricing is mental. It's not friendly to new businesses."
QuoteIQ$29/moPer-trade pricing built in, aimed squarely at small service shopsThe pricing layer is the paid part, which is the layer this page gives away.
Lowe's and Home Depot calculatorsFreeAccurate, quick, tied to real SKUs on the shelf, and they will drop it in a cart for youThey stop at quantity. No cost of yours, no markup, no margin, no job total, and the SKU they pick is the one they sell.
A spreadsheet you builtFree, plus your eveningsFits your business exactly, because you built it around your businessYou maintain it forever, the formulas rot quietly, and it lives on one laptop. Most of them are one broken cell reference away from a wrong bid.
This pageFreeQuantity, your cost, your markup, your margin and a job total on one screen, with the arithmetic shownIt cannot read a plan set. Everything below is the honest list.

Sources, August 2026: r/Construction threads on takeoff pricing and on a GC at roughly $4M revenue publishing the quotes he was given; Jobber, Procore, Buildertrend and QuoteIQ published or reported pricing; r/lawncare. Prices move — treat these as the shape of the market, not a quote.

Two honest notes about that table. None of these products are a rip-off for the customer they were built for. If you bid twenty commercial jobs a year off drawings, a takeoff package pays for itself in the first month, and the reason it costs $400 is that it is doing something genuinely hard. And the retailer calculators are good. They are not the enemy. They just stop one step before the step that decides whether you made money.

Where is this free tool genuinely enough?

It is enough if you look like this: one to five people, you measure with a tape and a measuring wheel, you bid off a site visit rather than a plan set, and you buy from two or three suppliers whose prices you already know. That is most residential contractors, most landscapers, most painters, most fence and deck builders, and every handyman.

For that shop it does everything the expensive one would do on the same job, because on that job the expensive one is also just multiplying length by width. You get the quantity in purchase units, your real prices saved so you stop retyping them, the waste built in on purpose instead of by accident, and the markup carried through to a margin you can defend at the kitchen table. Then a printable list to hand the supplier with quantities already in the units they sell.

It is not enough for five things, and they are worth saying out loud before you rely on it.

  • It cannot read a plan set. There is no PDF scaling, no digitiser, no symbol counting. If your work arrives as drawings, you want real takeoff software and this page will only slow you down.
  • It does not know your supplier's prices. There is no live feed. You type them once, it remembers them on that device, and you update them when they move. That is a feature in one sense — nobody can quietly change your cost basis — and a chore in another.
  • It does not do labor. Material is one line on an estimate. Labor, overhead and the drive time are the rest, and they usually decide the job. Use the hourly rate calculator for that half.
  • It does not sync. Saved prices live in one browser on one device. Switch phones and they are gone. Export the CSV if you want a copy you keep.
  • It does not track what you actually used. Estimated versus actual is job costing, and that is a different tool. Every trade underestimates something consistently, and the only way to find out which one is yours is to record it.

How do you use it?

  1. Pick the material. Each mode asks for the measurements that material is sold against, which is why the roofing mode wants a footprint and a pitch rather than a length and a width.
  2. Measure the finished surface, not the room. Walls minus doors and windows for paint. Roof footprint including overhangs, not the floor plan. Bed area, not the whole yard.
  3. Set the waste factor deliberately. Every mode loads with a default and a reason next to it. Raise it for curves, cut-up roofs, diagonal layouts and anything you had to estimate rather than measure.
  4. Put your real prices in. The placeholders are there so the page shows a live answer the second it loads. They are not your prices. Overwrite them and tick the save box.
  5. Set the markup and read the margin underneath it. Those are two different numbers and the tool prints both, along with the markup you would need to hit the margin you actually want.
  6. Add each material to the job. When everything is on the list you get one cost, one price and a blended margin across the whole job, then a CSV for the office or a printed list for the supply house.

What are the constants this calculator runs on?

Everything below is either a fixed conversion, which never changes, or a rule of thumb, which is labelled as one and given as a range. Knowing which is which is most of the skill. Cubic feet per cubic yard is a fact. Square feet per gallon of paint is an opinion with a lot of experience behind it.

The conversions that never move

ConversionValueWhere it bites
Cubic feet in a cubic yard27Everything sold in yards: concrete, mulch, soil, stone
Square feet in a square (roofing)100Shingles, underlayment, labor pricing
Pounds in a ton2,000Quarry tickets, which are almost always in tons
Inches to feet÷ 12Every depth and thickness on this page
Coverage of one cubic yard at 1 inch deep324 sq ftDivide 324 by the depth in inches to get square feet per yard
Roof pitch multiplier√(1 + (rise ÷ 12)²)Footprint to actual roof area
Board feet(nominal thickness × nominal width × length in ft) ÷ 12Lumber quotes, which are often per thousand board feet

What one cubic yard covers

This is the single most useful table in landscaping, and it is just 324 divided by the depth.

DepthSquare feet per cubic yardCubic yards per 1,000 sq ftTypical use
1 in3243.09Top-dressing a lawn
2 in1626.17Mulch refresh over an existing bed
3 in1089.26New mulch bed, the standard depth
4 in8112.35Gravel base, topsoil for new lawn
6 in5418.52Driveway base, drainage stone
8 in40.524.69Heavy base under a slab or a track
12 in2737.04Raised beds, backfill

Roof pitch multipliers

Multiply the footprint the roof covers by this number to get the actual sloped area. The formula is the square root of 1 plus the rise over 12, squared — straight Pythagoras, no rule of thumb involved.

PitchArea multiplierAngle1,800 sq ft footprint becomes
1/121.00354.8°1,806 sq ft — 18.06 squares
2/121.01389.5°1,825 sq ft — 18.25 squares
3/121.030814.0°1,855 sq ft — 18.55 squares
4/121.054118.4°1,897 sq ft — 18.97 squares
5/121.083322.6°1,950 sq ft — 19.50 squares
6/121.118026.6°2,012 sq ft — 20.12 squares
7/121.157730.3°2,084 sq ft — 20.84 squares
8/121.201933.7°2,163 sq ft — 21.63 squares
9/121.250036.9°2,250 sq ft — 22.50 squares
10/121.301739.8°2,343 sq ft — 23.43 squares
11/121.356642.5°2,442 sq ft — 24.42 squares
12/121.414245.0°2,546 sq ft — 25.46 squares

Above about 7/12 you are also into steep-slope labor rates and a harder day, which is a pricing conversation rather than a material one. The multiplier only tells you how much shingle to buy.

What bulk material weighs

These are rules of thumb, and the range is wide on purpose. Moisture is the biggest variable: topsoil that has sat in the rain can be a third heavier than the same soil dry, and you pay for water by the ton. Every quarry publishes its own conversion and theirs is the one that will be on your ticket.

MaterialPounds per cubic yardTons per cubic yardCubic yards per ton
Hardwood bark mulch800–1,0000.40–0.502.0–2.5
Pine bark mulch or nuggets500–8000.25–0.402.5–4.0
Compost1,000–1,4000.50–0.701.4–2.0
Screened topsoil, dry2,000–2,4001.00–1.200.83–1.00
Screened topsoil, wet2,700–3,0001.35–1.500.67–0.74
Fill dirt2,000–2,7001.00–1.350.74–1.00
Mason or play sand, dry2,400–2,7001.20–1.350.74–0.83
Pea gravel2,700–2,9001.35–1.450.69–0.74
Crushed stone 3/4 in (#57)2,700–2,8001.35–1.400.71–0.74
Crusher run / road base2,900–3,2001.45–1.600.63–0.69
River rock2,600–2,8001.30–1.400.71–0.77
Decomposed granite2,700–3,0001.35–1.500.67–0.74
Lava rock1,000–1,4000.50–0.701.4–2.0

The practical version: a yard of anything stony is somewhere near a ton and a half, a yard of mulch is about half a ton, and a yard of wet topsoil is heavier than both. A tandem dump truck legally carries around 10 yards of light material and rather less stone, which is why big stone orders arrive in more trips than you expected.

Coverage constants by trade

MaterialCoverageFixed or rule of thumb
80 lb bag of concrete0.60 cu ft — 45 bags per cubic yardFixed (printed on the bag)
60 lb bag of concrete0.45 cu ft — 60 bags per cubic yardFixed
50 lb fast-setting bag0.375 cu ft — 72 bags per cubic yardFixed
40 lb bag of concrete0.30 cu ft — 90 bags per cubic yardFixed
Interior paint on smooth drywall350–400 sq ft per gallon per coatRule of thumb
Paint on siding, render or rough surfaces250–350 sq ft per gallon per coatRule of thumb
Primer200–400 sq ft per gallon, depending how thirsty the surface isRule of thumb
Asphalt shingles3 bundles per square (4–5 for heavy designer)Fixed by product
Synthetic underlayment10 squares per rollFixed by product
#15 felt / #30 felt4 squares / 2 squares per rollFixed by product
Hip and ridge cap20–25 linear ft per bundleRule of thumb — check the wrapper
Starter strip100–120 linear ft per rollRule of thumb
Roofing nails320 per square at 4 per shingle; about 140 nails per pound of 1 1/4 in coilRule of thumb — roughly 2.3 lb per square
Drywall sheets4×8 = 32, 4×9 = 36, 4×10 = 40, 4×12 = 48 sq ftFixed
Drywall screwsAbout 1 per sq ft; roughly 320 of the 1 1/4 in screws per poundRule of thumb
Joint compoundA 4.5 gallon box covers about 450 sq ft to a standard finishRule of thumb — 400 to 500
Drywall tapeAbout 0.5 linear ft per sq ft of board; a 500 ft roll does about 1,000 sq ftRule of thumb
SodPallet covers 400–500 sq ft; a 16 in × 24 in slab is 2.67 sq ftVaries by farm — ask
Thinset, 50 lb bagSee the trowel table belowRule of thumb

Seed rates, pounds per 1,000 square feet

GrassNew lawnOverseedNote
Kentucky bluegrass2–3 lb1–1.5 lbTiny seed, spreads by rhizome, slow to germinate
Tall fescue6–10 lb4–6 lbBig seed, so the rate looks heavy and is not
Perennial ryegrass6–9 lb4–6 lbFast up, often used as a nurse grass
Fine fescue4–5 lb2.5–3.5 lbShade tolerant, hates traffic
Bermuda, hulled1–2 lb0.5–1 lbWarm season, needs soil above 65°F
Zoysia1–2 lb0.5–1 lbSlow. Most zoysia goes in as sod for a reason
Bahia5–10 lb3–5 lbScarified seed germinates far better
Centipede0.25–0.5 lb0.25 lbAlmost impossible to spread evenly without a carrier

Insulation R-value per inch

MaterialR per inchInches for R-49
Blown fibreglass2.2–2.718–22 in
Fibreglass batt3.1–3.414.5–16 in
Mineral wool batt3.0–3.315–16.5 in
Blown cellulose3.2–3.813–15.5 in
Open-cell spray foam3.5–3.713–14 in
EPS rigid board3.6–4.211.5–13.5 in
XPS rigid board4.5–5.010–11 in
Polyiso rigid board5.6–6.57.5–9 in
Closed-cell spray foam6.0–7.07–8 in

Thinset coverage and the grout formula

Trowel notchSquare feet per 50 lb bagTypical tile
1/4 × 1/4 in square90–100Mosaic and small format up to 8 in
1/4 × 3/8 in60–7012 × 12 and 12 × 24
1/2 × 1/2 in40–45Large format, 18 in and up
3/4 × 3/4 in22–28Very large format and stone

Grout is the one formula on this page worth memorising, because grout coverage charts are useless the moment your tile is not the size they assumed. The industry rule is:

Pounds of grout per square foot = [(tile length + tile width) ÷ (tile length × tile width)] × tile thickness × joint width × 14.5, with every dimension in inches.

For a 12 × 12 tile, 3/8 in thick, with a 1/8 in joint: (24 ÷ 144) × 0.375 × 0.125 × 14.5 = 0.1133 lb per square foot. Over 240 sq ft that is 27.2 lb, so two 25 lb bags. That formula runs deliberately generous — it assumes some grout stays in the bucket and on the float, which it does — so if you come out at 1.05 bags, buy two anyway and use the rest on the next job.

Standard waste factors, and why each one is what it is

Waste is not padding and it is not a fudge factor for bad measuring. It is the material that physically cannot end up on the job: offcuts, breakage, the wedge left in the mixer, the half shingle that dies in a valley. Order without it and you take a second trip, which costs more than the material did.

WorkDefaultRangeWhy
Concrete slab10%5–10%Subgrade is never as flat as the string line says, forms spread, and a truck that runs short leaves you a cold joint you will warrant
Concrete footing or trench10%10–15%Trenches over-dig. Nobody has ever dug a trench narrower than they meant to
Bulk aggregate and mulch10%5–15%Settling, ground that is not level, and the material that stays stuck in the bed of the truck
Paint5%0–10%Low, because you round up to a whole gallon anyway. Higher if you are cutting in several colours
Roof — simple gable or shed10%8–12%Starter course and the ridge, mostly
Roof — hips and a few valleys15%12–18%Every valley throws away half a shingle at a time, all the way up
Roof — cut up, dormers, turrets20%18–22%More cut edge than field. Some cut-up roofs genuinely hit 25%
Drywall10%10–15%Openings, soffits and short walls that eat half a sheet each
Sod5%5–10%Square yards waste almost nothing. Curved beds mean cutting every piece on the edge
Seed5%5–10%Spreader overlap and the pass you do at the edge
Fence posts and rails5%5–10%You will crack one and find one bowed. Pickets run higher than posts
Decking, straight lay10%8–12%End cuts, and the board with the shake in it you send back
Decking, diagonal or picture frame15–20%15–22%Every board gets two angle cuts and the offcut is not reusable
Flooring, straight lay10%8–12%End of row cuts, and the plank that comes out of the box damaged
Flooring, diagonal or large format15%12–18%Angle cuts at every wall
Flooring, herringbone or chevron20%18–25%The pattern itself creates offcuts that do not fit anywhere else
Tile10–15%10–20%Add 5 points if the room is out of square, and always buy attic stock — dye lots do not repeat
Insulation5%5–10%Batts get trimmed around wiring and blocking

Why is a 25% markup only a 20% margin?

Because they are measured against different things. Markup is a percentage of what the material cost you. Margin is a percentage of what the customer paid. The customer paid more, so the same dollars are a smaller share of it.

Worked out on the slab from the top of this page. The concrete costs you $2,852.50. Add 25% markup, which is $713.13, and you charge $3,565.63. Your profit is $713.13 on a price of $3,565.63, and $713.13 ÷ $3,565.63 is 20.0%. You added 25 and kept 20.

The formula in both directions: margin = markup ÷ (1 + markup), and markup = margin ÷ (1 − margin). Both in decimals.

If you mark up byYour margin isTo keep this marginMark up by
10%9.1%10%11.1%
15%13.0%15%17.6%
20%16.7%20%25.0%
25%20.0%25%33.3%
30%23.1%30%42.9%
35%25.9%35%53.8%
40%28.6%40%66.7%
50%33.3%45%81.8%
75%42.9%50%100.0%
100%50.0%60%150.0%

The r/Contractor thread titled "25% Markup on materials?" shows there is no shared vocabulary for this at all. One reply: "I've seen 50-100% mark up on material." Another: "I run a 50% markup on labor and material. Labor is a cost. Not profit." Both of those people are describing completely different businesses and using the same words. Whatever number you land on, know which of the two you are quoting, because the gap between them is your entire profit on a good year.

Ten calculations worked longhand

Every one of these is what the tool above does when you type the same numbers in. They are here so you can check the tool rather than trust it.

  1. Concrete slab. 20 ft × 60 ft at 4 in. 20 × 60 = 1,200 sq ft. 4 ÷ 12 = 0.3333 ft. 1,200 × 0.3333 = 400 cu ft. 400 ÷ 27 = 14.81 cu yd. Plus 10% waste = 440 cu ft = 16.30 cu yd, ordered as 16.50. In 80 lb bags: 440 ÷ 0.60 = 734 bags, which is why nobody bags a driveway.
  2. Concrete steps. 4 steps, 7 in rise, 11 in run, 4 ft wide. The stepped solid is 7 × 11 × (4 × 5 ÷ 2) = 770 sq in in section, which is 5.35 sq ft. × 4 ft wide = 21.39 cu ft = 0.79 cu yd, or 0.87 with 10% waste. That is 40 eighty-pound bags, or one very small short load.
  3. Roofing with pitch. 1,800 sq ft footprint at 6/12. Multiplier √(1 + 0.5²) = √1.25 = 1.1180. 1,800 × 1.1180 = 2,012.46 sq ft = 20.12 squares. Plus 15% for hips and valleys = 23.14 squares. At 3 bundles a square: 69.4, so 70 bundles. Underlayment at 10 squares a roll: 3 rolls.
  4. Interior paint. 14 ft × 16 ft room, 9 ft walls, two doors, three windows. Perimeter 2 × (14 + 16) = 60 ft. 60 × 9 = 540 sq ft gross. Less 2 × 21 = 42 and 3 × 15 = 45, so 453 sq ft net. Plus 5% = 475.65. Two coats = 951.3 sq ft. ÷ 350 = 2.72, so 3 gallons.
  5. Gravel by the ton. A 40 ft × 12 ft driveway at 4 in of #57 stone. 480 sq ft × 0.3333 = 160 cu ft ÷ 27 = 5.93 cu yd. Plus 10% = 6.52 cu yd. At 1.4 tons per yard that is 9.13 tons. Quoted at $36 a ton that is $328.68. The same pile bought by the yard, rounded up to 7 yards at $48, is $336.00 — same stone, two tickets, which is why you check which unit the quote is in before you compare two prices.
  6. Drywall. 14 × 16 room with 9 ft walls and a boarded ceiling. Walls 60 × 9 = 540 sq ft, ceiling 224 sq ft, total 764. Plus 10% = 840.4 ÷ 32 = 26.26, so 27 sheets of 4×8. Compound: 764 ÷ 450 = 2 boxes. Tape: 764 × 0.5 = 382 ft, so 1 roll of 500.
  7. Fence posts and concrete. 200 linear ft in 3 separate runs at 8 ft spacing, one gate. 200 ÷ 8 = 25 sections. 25 + 3 for the run ends + 2 for the gate = 30 posts. Each 10 in hole 30 in deep holds π × (5 ÷ 12)² × 2.5 = 1.3635 cu ft, less the 3.5 in post at 0.2127, so 1.1508 cu ft per hole. × 30 = 34.52 cu ft ÷ 0.375 = 93 bags of 50 lb fast-set, about three a hole.
  8. Decking boards. 16 ft × 12 ft deck, 5.5 in boards, 3/16 in gaps. Each board covers 5.6875 in, which is 0.4740 ft. 12 ft ÷ 0.4740 = 25.32, so 26 rows. Each row is 16 ft, so 416 linear ft, plus 10% = 457.6 ÷ 16 = 29 boards at 16 ft. Joists at 16 in centres over 16 ft: (16 × 12 ÷ 16) + 1 = 13 joists at 12 ft.
  9. Tile boxes. 240 sq ft laid diagonal, 15% waste. 240 × 1.15 = 276 sq ft. Boxes at 15.5 sq ft: 276 ÷ 15.5 = 17.8, so 18 boxes. Thinset with a 1/4 × 3/8 trowel at 65 sq ft a bag: 240 ÷ 65 = 4 bags.
  10. Blown attic insulation. 1,200 sq ft attic, existing R-11, target R-49, cellulose at R-3.5 an inch. You need R-38 more, which is 38 ÷ 3.5 = 10.9 in of new material. At 28 sq ft a bag at R-30, one bag covers 28 × 30 ÷ 38 = 22.11 sq ft at R-38, so 1,200 sq ft plus 5% waste is 1,260 ÷ 22.11 = 57 bags.

What goes wrong most often?

Six mistakes account for nearly all of the material misses on small jobs, and none of them are hard arithmetic.

  • Mixing units without noticing. Depth in inches into a formula that wants feet is the classic, and it is off by a factor of twelve, which is big enough to be obvious and small enough to slip through if you are in a hurry. This page always converts on screen so you can see it happen.
  • Buying stone in yards when the quarry sells tons. Or the reverse. Ask which unit the quote is in before you compare two quotes.
  • Using the floor plan for a roof. The footprint includes overhangs and it is not the same as the conditioned square footage. Then the pitch multiplier goes on top of that.
  • Forgetting that paint coverage is per coat. Two coats on 450 sq ft is 900 sq ft of paint, not 450. Half the gallons people run short on come from this.
  • Rounding down. Material comes in bags, bundles, boxes and rolls, and you cannot buy 17.8 boxes. Round up every purchase unit, every time. Twenty dollars of leftover tile is cheaper than an afternoon and a dye lot that no longer matches.
  • Pricing at cost. Handling, hauling, storing, returning and warranting material is work. Nobody pays you for it separately, which is exactly what the markup is for. Marking material at zero is the quietest way to work for free.

One more that is not arithmetic at all. Material prices move mid-job, and on a long job that is your problem unless the contract says otherwise. Two r/Contractor threads on price escalation ran to 98 and 121 comments and the consensus was the same: put a validity date on the estimate — 14 or 30 days — and an escalation clause on anything with a long lead time. The estimate generator has a spot for both.

Common questions

How much mulch do I need?

Multiply the bed area in square feet by the depth in inches, divide by 12 to get cubic feet, then divide by 27 to get cubic yards. One cubic yard covers 324 square feet one inch deep, so it covers 108 square feet at 3 inches and 81 square feet at 4 inches. A 1,000 square foot bed at 3 inches is 250 cubic feet, 9.26 cubic yards, or about 10.2 yards once you add 10% for settling and uneven ground.

How do I figure concrete for a slab?

Length in feet times width in feet times thickness in inches divided by 12 gives cubic feet. Divide by 27 for cubic yards. A 20 by 60 foot slab at 4 inches is 1,200 square feet times 0.3333 feet, which is 400 cubic feet, which is 14.81 cubic yards. Add 10% for subgrade that is never as flat as you think and order 16.3 yards, because a truck that runs short leaves you with a cold joint.

When is a concrete truck cheaper than bags?

Sooner than most people think. It takes 45 eighty-pound bags to make one cubic yard, so at $6.50 a bag that yard costs $292.50 in material alone. Ready-mix at $175 a yard plus a $100 short-load fee beats bags at about 0.85 of a cubic yard. Under that, bags win. Over about a yard, the truck wins on price and wins by a mile on labor, and the calculator works the crossover out with your actual prices.

How do I calculate roofing squares with pitch?

Take the footprint the roof covers in square feet and multiply by the pitch multiplier, which is the square root of 1 plus the rise over 12 squared. A 6/12 roof multiplies by 1.1180 and a 12/12 roof multiplies by 1.4142. Divide by 100 for squares. An 1,800 square foot footprint at 6/12 is 2,012 square feet of roof, 20.12 squares, and 23.14 squares once you add 15% for hips and valleys.

How much paint do I need for a room?

Perimeter times wall height gives gross wall area. Take off 21 square feet per door and about 15 per window. A gallon covers 350 to 400 square feet a coat on smooth drywall and 250 to 350 on siding or rough render. A 14 by 16 foot room with 9 foot walls, two doors and three windows is 453 square feet net, 951 square feet over two coats, and three gallons.

How many tons of gravel is a cubic yard?

About 1.4 tons for 3/4 inch crushed stone, because a cubic yard of it weighs roughly 2,700 to 2,800 pounds. It varies by material and by how wet it is: mulch runs 0.4 to 0.5 tons a yard, screened topsoil 1.0 to 1.2, sand 1.2 to 1.35, and crusher run 1.45 to 1.6. Every quarry publishes its own figures and they are the ones that will be on your ticket, so ask.

What waste factor should I use?

Ten per cent is the honest default for most volume and sheet work. A simple gable roof takes 10%, hips and valleys take 15%, and a cut-up roof takes 18% to 22%. Straight-lay flooring takes 10%, diagonal 15% and herringbone 20%. Paint takes about 5% because you round up to the gallon anyway. Waste is not padding. It is offcuts, breakage, the bit that stays in the truck, and the second trip you do not want to make.

Why is a 25% markup not a 25% margin?

Because markup is measured against your cost and margin is measured against your price. Add 25% to $2,850 of material and you charge $3,562.50 and keep $712.50, which is 20.0% of what the customer paid, not 25%. To actually keep 25% you need a 33.3% markup. As a contractor put it on r/Contractor in June 2026, a 30% markup is only a 23% margin, and on a $10,000 job that is $700 you are leaving on the table every single time.

Is this as accurate as takeoff software?

For quantities from measurements you already have, yes, because it is the same arithmetic. What it will not do is read a set of plans. Takeoff packages at $200 to $500 a month let you scale off a PDF drawing, count fixtures with a click, and keep an assembly library, and if you bid off plans all day that is worth paying for. If you measure the site with a tape and a wheel, you are paying for a plan reader you do not use.

Is this really free, and does it save my prices?

It is free, with no signup and no email gate, and nothing you type leaves your device. Supplier prices and your job list save only if you tick the save box, and then only in this browser on this device. Clear your browser data or pick up a different phone and they are gone. Export the CSV if you want a copy you keep.

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Quantities include the waste factor shown against each line. Estimates for planning, not tax or legal advice. Check against your own measurements before you order. Built with the free material calculator at phitweb.com/tools/material-calculator