DIY calculators that show their working
Work out how much paint, tile, concrete or lumber to buy before you go to the store. Every calculator explains the maths and the assumptions behind it.
Walls and ceilings
Paint, wallpaper and drywall for a room.
Paint Calculator Gallons or liters of paint for walls and ceilings after doors and windows, and which cans to buy.Wallpaper Calculator Rolls of wallpaper for a room, allowing for the pattern repeat, doors and windows.Drywall Calculator Sheets of drywall for walls and ceilings, with screws, joint tape and compound.
Floors and tiles
Room area, tiles and flooring packs.
Tile Calculator Tiles and boxes for a floor or wall, with grout joints and a waste allowance.Flooring Calculator Boxes of laminate, vinyl plank or hardwood for one or more rooms, with cutting waste, baseboard and underlayment.Square Footage Calculator Floor area of rooms in any shape, in square feet and square meters.
Garden and concrete
Slabs, footings, mulch, soil and gravel.
Wood, stairs and roofs
Board feet, stair layout and roof pitch.
Board Foot Calculator Board feet and cost of lumber from thickness, width, length and price.Stair Calculator Number of steps, riser height, tread depth and stringer length, checked against building rules.Roof Pitch Calculator Convert roof pitch between x/12, degrees and percent, and find rafter length.
Measuring
Tape-measure maths with feet, inches and fractions.
How these calculators work
The formula is on the page
Each calculator explains how the result is worked out, with an example you can check by hand.
Figures come with a source
Coverage rates, product sizes and building rules link to the page we checked and the date we checked it.
What you type stays on your device
Everything is calculated in your browser. There is no account and nothing you type is sent to us.