Home improvement
Paint Calculator
Estimate paint for the walls and optional ceiling of a rectangular room. Nothing you enter leaves your browser.
Enter your values, then calculate.
Calculation method
A transparent estimate.
Every adjustable assumption stays visible, so you can understand what drives the result and tailor it to your situation.
(wall area − openings + optional ceiling) × coats ÷ label coverageWhat this estimate assumes
- Wall area is 2 × (length + width) × height.
- The 350 ft²/gal default is conservative within the typical 350–400 ft²/gal range.
- Only subtract large openings you measured; texture and application method can change real coverage.
Research sources
What this tool does
About the Paint Calculator
Estimate paint for the walls and optional ceiling of a rectangular room. It is a planning estimate for ordering materials. Real projects should include waste, site conditions, and manufacturer guidance.
The calculation uses measurement system, room length, room width, wall height, large openings to subtract, include the ceiling?, number of coats, and coverage on the paint label.
How to use it
- Review the starting values for measurement system, room length, room width and replace them with your own.
- Choose any available units or assumptions, then select “Estimate paint.”
- Read the labeled result, compare another scenario if needed, and copy the output for your notes.
Practical example
Start with a known input
The workbench starts with a complete scenario: Measurement system: us Room length: 12 ft Room width: 10 ft Wall height: 8 ft Change one assumption at a time to see how it affects the result.
What to know about the result
- Results are estimates based only on the supplied values. Rounding, fees, local rules, and real-world conditions may change the final outcome.
Common questions
Using the Paint Calculator
Is the Paint Calculator free to use?
Yes. FormatCalc's Paint Calculator is free to use with no account required.
Is my data private when I use the Paint Calculator?
Yes. This tool processes your input locally in your browser. FormatCalc does not upload or store what you enter.
How do I use the Paint Calculator?
Enter your values, select any units, and choose Estimate paint. You can then copy the result.
How is the Paint Calculator calculated?
It uses (wall area − openings + optional ceiling) × coats ÷ label coverage. The result is a planning estimate based on the values and assumptions shown on this page.