Use a calculator

Each calculator is a form with the result beside or below it. The result updates as you type.

Find a tool#

1. Go to Tools, or tap Tools in the app's navigation.
2. Pick a tool from its group, or type in Search the tools (for example, "tiles" or "skirting").
3. If you search for something we don't calculate, such as a lintel or a cable size, the search offers the guidance page for it instead.

Set it up#

1. Choose Metric or Imperial under Units. Signed in, the tools start in the units from Settings, under Language, region and units. Switching on the tool page doesn't change your setting.
2. Choose the Shop sizes: United Kingdom, France or Spain. They set things like tin sizes, roll and board sizes, and the usual door and window sizes. Any value still at the old default moves to the new one.
3. Fill in your measurements. Some tools let you add several rooms, walls or surfaces.
4. Set the Waste allowance for offcuts, spills and breakages, where the tool has one.
5. Open More options for the less common settings.

Read the result#

1. You'll need shows the headline figure and what to buy, in whole tins, boxes, rolls or bags.
2. Open How it's worked out to see each step of the sum.
3. Related tools links to the tools that usually come next, such as grout after tiles.
4. Some tool pages have a Not calculated here note that links the guidance for regulated work the tool touches, such as foundations under paving.

On a phone, a bar at the bottom shows the headline figure while the result is off screen.

Fill from a floorplan#

When you're signed in and one of your projects has a floorplan, the paint, flooring, skirting, radiator and air-con calculators offer Fill from a floorplan. Pick a room and tap Fill in: its measurements, doors and windows are filled in for you. See Save a floorplan to your project.