Fast, free calculators and tools for everyday problems.

Paint Calculator

Estimate paint needed based on wall dimensions, coats, coverage rate, and openings.

Inputs

Fields marked with * are required.

Unit system*Wall width*Measure the width of the wall or surface in your selected unit system.Wall height*Measure the wall height in your selected unit system.Number of doors*Each door subtracts about 20 square feet or 1.86 square meters.Number of windows*Each window subtracts about 15 square feet or 1.39 square meters.Number of coats*Enter how many coats of paint you plan to apply.Coverage per gallon or litre*Use square feet per gallon for imperial or square meters per litre for metric.

Results

Your result updates after a successful calculation.

Estimated paintable area

110

Wall area after subtracting doors and windows in the selected unit system.

Gallons Needed

0.63

Approximate paint required based on coverage, coats, and the selected unit system.

Unit summary

Results shown in square feet and gallons.

Indicates whether the result uses imperial or metric paint wording.

How it works

Short formula and logic summary for this tool.

The calculator multiplies width by height, subtracts standard door and window area, then scales the remaining area by the number of coats and the selected coverage rate.

Worked example

A 20 by 8 foot wall with one door, two windows, two coats, and typical imperial coverage needs about 0.63 gallons of paint.

unitSystem: imperial
width: 20
height: 8
doors: 1
windows: 2
coats: 2
coveragePerGallon: 350

FAQ

Common questions about this tool.

Does this include doors and windows?

Yes. This version subtracts standard door and window area from the total paintable surface.

Why enter coats?

Extra coats increase the total paint required.