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THE TOOLKIT / 01

Paint calculator

Estimate paint for the four walls of a rectangular room. Include openings, coats, coverage and a little room for touch-ups.

Free to use · No account needed · Imperial & metric
THE MEASUREMENTS
Product details & price
Total area to subtract. Only include surfaces you will not paint.
Use the coverage printed on your chosen paint, per coat.
Display currency only; no exchange-rate conversion.

Your measurements stay in your browser.

YOUR MATERIAL ESTIMATE

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Enter your measurements to make a plan.

Estimated material cost—

Uses your entered or example price. Excludes tax, tools, delivery and labor.

Walls only. Ceiling, trim, primer and labor are not included. The 10% extra allowance is an editable planning assumption, not a product requirement.

THE MATH, WITHOUT THE MYSTERY

How this estimate works

Wall area = 2 × (length + width) × height − openings. Paint = wall area × coats × (1 + allowance ÷ 100) ÷ coverage. Round up to whole cans.

A worked example

A 12 × 10 ft room with 8 ft walls has 352 ft² of wall. Subtract 40 ft² of openings, apply two coats and add 10%: 686.4 ft² of coverage. At 350 ft² per US gallon, that is 1.96 gallons, or two 1-gallon cans.

Read the complete calculation note

A FEW USEFUL ANSWERS

Before you buy

Does this include the ceiling?

No. For a flat ceiling, calculate length × width separately, multiply by coats, and divide by the ceiling paint coverage. Trim and doors also need their own estimate.

Should I deduct every door and window?

You can enter the total unpainted area for a more exact geometric estimate. On a small project, leaving small openings undeducted can provide a buffer. Keep your choice consistent and check your paint label.

What changes when I select metric?

The existing project measurements, coverage and can volume are converted. The physical can size and price stay equivalent, so changing units alone should not change the buying quantity. Enter a different can size if your local shop sells a different volume.