Paint Calculator

Estimate how much paint you need for your room, including deductions for windows and doors. Enter your room dimensions and paint type below, or choose a popular room type and size to get started.

Popular Room Calculators

About This Calculator

Our paint calculator helps you estimate how much paint to buy for your decorating project. Enter your room dimensions and choose your paint type to get an approximate quantity, with deductions for windows and doors.

The calculator suggests how many litres of paint to buy and recommends suitable tin sizes so you know what to look for at B&Q, Wickes, or your local decorating shop. Results are based on standard coverage rates from brands like Dulux and Crown.

Window and Door Deductions

We deduct 1.2m² per window (based on a standard UK window opening) and 1.8m² per door (based on a standard UK internal door with frame). If your windows or doors are significantly larger than average, you may wish to adjust the count accordingly.

These calculations are estimates based on standard manufacturer coverage rates. Actual quantities may vary depending on surface conditions, wastage, and application technique. Always verify quantities with your supplier before purchasing.