Project Material Calc: home improvement material calculators
Work out how much material to buy before you go to the store. Enter your measurements in metric or US units, and read how each result is calculated.
Last updated: September 29, 2026
Walls and finishes
Calculators for paint, wallpaper, wall and floor tile, and drywall or plasterboard: cans, rolls, boxes and sheets for a room.
- PaintHow much paint or primer for a room, one wall, a ceiling or doors and trim: litres or gallons and cans, with a table for 10×10, 12×12 and 12×14 ft rooms.
- WallpaperCalculate how many rolls of wallpaper to buy from the width and height of the walls, the roll size and the pattern repeat.
- TileHow many tiles and boxes for a floor, shower walls or a backsplash, with extra for diagonal and herringbone layouts, plus bags of grout and thinset.
- DrywallCalculate how many sheets of drywall or plasterboard a room needs from its size, the openings, the sheet size and an allowance for cuts.
Floors and outdoor
Calculators for flooring, decking, concrete, fence posts, paver patios and block walls, and for gravel, mulch and topsoil by the bag, cubic yard or ton.
- FlooringCalculate how many boxes of laminate, vinyl plank, engineered wood or carpet tile to buy from the room size, the coverage of one box and an allowance for cuts.
- DeckingCalculate how many deck boards and joists a rectangular deck needs from its size, the board width and length, the gap between boards and the joist spacing.
- ConcreteConcrete for a slab, strip footing, Sonotube column or steps in cubic yards or m³, and bags of 40 to 80 lb or 20, 25 or 30 kg if you mix it yourself.
- Fence post concreteHow many bags of concrete per fence post: round or square holes, 4×4 or 100 mm posts, a gravel base, and bag sizes for the US, Canada, UK, Australia and NZ.
- GravelHow much gravel for a driveway, path or French drain: cubic yards or m³, tons or tonnes and truckloads, with stone presets based on supplier weights.
- MulchHow many bags or cubic yards of mulch for a rectangular or round bed or a ring around a tree, with 1.5, 2 and 3 cu ft bags or 50 to 100 L bags.
- TopsoilHow much topsoil or raised bed soil to buy: cubic yards or m³, bags and approximate weight for a lawn or garden area or for several raised beds.
- Paver patioHow many pavers for a patio, with joint width, a pattern allowance, the base gravel and bedding sand in cubic yards and tons, edging, and round fire-pit patios.
- Retaining wallHow many retaining wall or garden wall blocks, caps and tons of base and drainage gravel you need, including round fire pits, with the height limits to know.
Structure and measuring
Calculators for room area, bricks and mortar, stair risers and treads, roof pitch in x/12 and degrees, and roof area with shingle bundles.
- Room areaCalculate the floor area of a rectangular, L-shaped or irregular room in square metres and square feet, with the perimeter for skirting and trim.
- BrickCalculate how many bricks a wall needs from its size, the brick size and the mortar joint, with a breakage allowance and the volume of mortar in the joints.
- StairsRisers, treads, total run and a stringer layout to 1/16 in or 1 mm, with the first-riser cut, a throat check for 2×12 or 2×10 and landings when needed.
- RoofingCalculate the area of a pitched roof from its footprint and pitch, and the number of bundles of shingles to buy, with an allowance for waste.
- Roof pitchConvert roof pitch between rise and run, inches per 12, degrees and percent, get the pitch multiplier and a pitch chart, and learn how to measure it.
How the calculators work
Every calculator opens with a complete example, so you can see what it expects before you type anything. Replace the example values with your own measurements and select Calculate.
Each page explains the formula in plain words and repeats the example step by step, so you can check the result with a pocket calculator.
Quantities that you buy in whole units, such as cans, boxes, bags, rolls, sheets and bundles, are always rounded up. The allowance for cuts and breakage is added before rounding.
In US units, lengths can be typed the way a tape measure reads: 12' 6", 12 6 for feet and inches, or 7 3/4 in. Lengths such as riser heights and perimeters are also shown to the nearest 1/16 in.
Before you buy
- Measure every wall or floor yourself. Plans and listings are often rounded.
- Check the label of the product you are buying: coverage, pack size and yield differ between brands and countries. The values in the calculators are examples.
- Buy material for one job from one batch where colour or pattern matters, for example tiles, wallpaper and flooring.
- Ask the store about its return policy for unopened packs before you add a generous allowance.
What the calculators do not do
The results are estimates of quantity. They are not structural design, and they do not replace your local building code, the instructions of the manufacturer or the advice of a qualified professional.
This matters most for stairs, decks, roofs, footings and load-bearing walls, where safety depends on more than the amount of material.
Frequently asked questions
- Are the calculators free?
- Yes. Every calculator is free and works without an account. The site may show advertisements to cover its costs.
- Do you store or receive my measurements?
- No. The calculation runs in your browser, and the numbers you enter are not sent to us. The browser remembers only your choice of units and appearance. If you copy a link to a result, the numbers are part of that link.
- Can I use metric and US units?
- Yes. Every calculator has a units control. Metric uses metres, millimetres, litres and tonnes. US units use feet, inches, US gallons, cubic yards and short tons. Note that the US gallon is smaller than the imperial gallon that was used in the United Kingdom and Canada.
- Why does the result round up?
- Stores sell whole cans, boxes and bags. Rounding down would leave you short, so the calculators round the quantity to buy up to the next whole unit.
- Do the calculators work without JavaScript?
- The explanation, the formula and the example result are readable without JavaScript. Calculating with your own numbers needs JavaScript.