Paint Calculator
Enter your wall dimensions, subtract doors and windows, and get the exact litres or gallons of paint you need.
How the paint calculator works
Add each wall by entering its width and height. The calculator sums the gross wall area, then subtracts standard deductions for doors (approximately 1.89 m² each) and windows (approximately 1.44 m² each). The net area is multiplied by the number of coats and divided by the coverage rate shown on your paint tin — typically between 8 and 14 m² per litre for emulsion — to give the total volume needed. Cans are rounded up so you always have enough paint for the job.
Switch between metric (m², litres) and imperial (ft², gallons) using the area unit selector. Enter the coverage figure from your specific paint tin's label for the most accurate result, as coverage varies by brand, surface porosity, and application method.
FAQ
What coverage should I enter? Check the paint tin label — emulsion typically covers 8–14 m² per litre on a smooth surface, but coverage halves on bare plaster or highly porous walls. Use the lower end for safety.
Does the calculator include the ceiling? Not automatically. Add the ceiling as an extra wall with width and length as dimensions.
Is my data sent anywhere? No. All calculations run locally in your browser.