How to Estimate Paint Needed in Excel

Build a paint calculator: wall area minus openings, coats, coverage per litre, and ROUNDUP to whole cans and a final cost.

You will learn to

• Calculate litres of paint for a room
• Round up to whole cans
• Price the whole job in one formula

How it works

To estimate paint, work out the wall area (perimeter × height), subtract doors and windows, multiply by the number of coats and divide by the coverage on the tin (for example 11 m² per litre). That gives litres; divide by the can size and ROUNDUP to whole cans, because you can’t buy 3.03 cans.

For a whole house, total the litres across rooms first and round up once at the end — rounding per room buys more cans than you need. SUMPRODUCT handles the area × coats calculation for every room in one formula, and the same template works for flooring, tiles or mulch.

=ROUNDUP((B2*C2-D2)*E2/B8/B9,0)