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Paint Calculator
Enter room size and coats to get gallons or liters — interior or exterior, waste included.
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Free tools for DIY & pros
How much paint, tile or concrete do you really need?
Enter a room or surface size and MaterialCalc tells you the exact quantity of paint, tile, concrete, mulch, flooring or shingles to buy — with realistic waste included. All 10 calculators are free, work in imperial and metric units, and use coverage rates based on published manufacturer data.
Paint Calculator Try it
ft
ft
coats
Units
--
Enter length and width to get started
Demo only — coverage varies by paint. See the full calculator for exact numbers.
Waste & coats included automatically
10
Free calculators
2
Unit systems
10–15%
Waste built in
0
Sign-ups needed
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Stop guessing. Get the exact amount for your project.
Each calculator covers the full chain: area → quantity → cost, so you buy the right amount the first time — and avoid a second trip to the store.
Exterior Paint Calculator
Measure exterior wall area for siding, brick or stucco — in square feet or square meters.
Open toolTile Calculator
How many tiles for a floor, wall or backsplash — with a 10% or 15% waste option.
Open toolMulch Calculator
Cubic yards or bags of mulch for any garden bed depth — bagged vs. bulk comparison.
Open toolConcrete Calculator
Slabs, footings and post holes — bags of mix vs. ready-mix, straight from the dimensions.
Open toolSod Calculator
Square feet, rolls and pallets of sod for a new lawn — with 5% cutting allowance.
Open toolGravel Calculator
Driveways, patios and drain beds — tons and cubic yards for any depth.
Open toolDrywall Calculator
Walls and ceilings — how many 4×8 or 4×12 sheets, cut waste included.
Open toolFlooring Calculator
Laminate, vinyl or hardwood — boxes and waste allowance set by installation method.
Open toolRoof Shingles Calculator
Bundles and squares for your roof, adjusted for pitch with the slope factor table.
Open toolHow it works
Three steps to the right quantity
1
Pick your material
Choose the calculator for your job — paint, tile, concrete, mulch or any of the 10 tools.
2
Enter your dimensions
Type in the room or surface size. Switch between feet/gallons and meters/liters freely.
3
Get the exact amount
See quantity in the units stores sell in — gallons, tiles, bags or yards — plus a cost estimate.
Why our numbers are right
Calculators built like a careful contractor
Manufacturer coverage data
Rates are cross-checked against published product data from paint, concrete and flooring brands.
Real waste allowances
Cutting, breakage and overlap are real problems — we default to the allowances pros use (10–15%).
Both unit systems
Built for the US (ft, gallons) and everywhere else (m, liters) — the calculator converts for you.
Formulas you can see
Every calculator shows its formula and a worked example, so you can verify the math by hand.
FAQ
Frequently asked questions
How do I know how much paint I need for a room?
Measure the length and width of the room, enter them into the paint calculator with the number of coats, and it returns gallons or liters including waste. As a rule of thumb, one gallon of interior paint covers about 350 square feet per coat.
How much extra tile should I buy?
Contractors buy 10% extra for straightforward layouts and 15% for diagonal patterns, large tiles or irregular rooms. This covers cutting waste and keeps a few spares for future repairs — discontinued tiles are almost impossible to match later.
Do the calculators work with metric units?
Yes. Every tool has an imperial/metric toggle. Switch from square feet to square meters, and quantities are shown in the unit you buy in — liters instead of gallons, bags sized for metric coverage.
Is MaterialCalc free to use?
Yes — every calculator is free, requires no account, and works on any device. We keep the site running through display ads and affiliate links to home improvement stores.
Why is my calculated amount different from the store's estimate?
Differences usually come from the waste allowance and the coverage rate used. Our defaults follow typical contractor practice, but you can adjust waste % and coverage on any calculator to match your specific product label.
Ready to start your project?
Pick a calculator, enter your room size, and get a shopping list in seconds.
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