Work out the materials for your project
Free calculators that work from your measurements and your product's own figures, and show every step of the sum.
An inch is exactly 2.54 centimetres.
That is the law: a yard is 0.9144 metres and an inch is a 36th of a yard. Convert inches to cm.
Calculators
Measuring
- Square metre calculatorThe area of a room or several rooms in square metres and square feet, from metric or imperial sizes.
- Square feet calculatorSquare footage of a room or several rooms, from sizes in feet and inches or metric.
- Area calculatorThe area of a rectangle, triangle, circle, semicircle or trapezium.
- Volume and cubic metre calculatorCubic metres, litres and cubic feet in a box or a cylinder.
Building
- Concrete calculatorCubic metres of concrete for a slab, footing, post holes or steps, and bags from the yield on the bag.
- Brick calculatorBricks for a wall from its size and your brick's size, with the mortar to lay them.
- Block calculatorConcrete or breeze blocks for a wall, a square metre at a time.
- Screed calculatorScreed for a floor, in cubic metres and bags.
- Plasterboard calculatorSheets of plasterboard for walls and ceilings.
Garden
- Gravel calculatorCubic metres of gravel for an area and depth, and tonnes or bags from your supplier's figures.
- Topsoil calculatorTopsoil for a lawn, border or raised bed.
- Sand calculatorSand for a base, a sandpit or bedding slabs.
- Hardcore and sub-base calculatorHardcore or MOT Type 1 for a sub-base under a patio, path or drive.
- Aggregate calculatorAny aggregate: area times depth, in cubic metres, tonnes and bags.
- Paving calculatorPaving slabs or block paving for a patio or drive, with the joints.
- Decking calculatorDeck boards and joists for a deck of any size.
- Fence calculatorFence panels and posts for a run of fence.
- Turf calculatorRolls of turf for a lawn, from the size of a roll.
- Pond liner calculatorThe size of liner for a pond, with the depth and an overlap at the edges.
Decorating
- Paint calculatorLitres and tins of paint for a room, from the coverage on the tin.
- Wallpaper calculatorRolls of wallpaper for a room, with the pattern repeat.
- Tile calculatorTiles for a floor or wall, with the grout joints, and boxes.
- Flooring calculatorPacks of laminate, vinyl or wood flooring, and rolls of carpet.
Stairs, roofs and slopes
- Stair calculatorNumber of steps, rise and going for a staircase, checked against the building regulations.
- Roof pitch calculatorRoof pitch in degrees and the rafter length, from the rise and the run.
- Ramp calculatorA ramp's gradient, checked against the building regulations for its length.
- Gradient and fall calculatorGradient as 1 in N, a percentage and an angle, or the fall over a length.
Converters
- Centimetres to inches
- Inches to centimetres
- Millimetres to inches
- Inches to millimetres
- Feet to metres
- Metres to feet
- Centimetres to feet and inches
- Feet and inches to centimetres
- Square feet to square metres
- Square metres to square feet
- Acres to hectares
- Hectares to acres
- Litres to gallons
- Gallons to litres
- Kilograms to stone and pounds
- Stone and pounds to kilograms
- Kilograms to pounds
- Pounds to kilograms
- Kilometres to miles
- Miles to kilometres
- Inches to feet
- Feet to inches
- Stone to pounds
- Pounds to stone
- Yards to metres
- Metres to yards
- Fluid ounces to millilitres
- Millilitres to fluid ounces
- Pints to litres
- Litres to pints
- Miles an hour to kilometres an hour
- Kilometres an hour to miles an hour
- Fahrenheit to Celsius
- Celsius to Fahrenheit
Guides
- Stair building regulations: rise, going, pitch and headroomApproved Document K's limits for stairs in homes and other buildings, in one place.
- Units and where they come fromEvery conversion factor and building regulation figure we use, with its legal source.
Why these calculators are different
We never guess the size of your brick, the coverage of your paint or the weight of your gravel. Those differ from product to product, so the calculators ask for them, and tell you where to find them: on the pack, the tin or from your supplier. Unit conversions use the legal definitions in the Weights and Measures Act 1985, and the stair and ramp calculators check your design against the building regulations' own guidance.
Figures checked 13 November 2026. How we work.