# Paint Coverage Calculator

> Paint coverage calculator: estimate gallons of paint needed for walls and ceilings by room size and coats. Free, private, runs in your browser, no signup.

- **Canonical URL:** https://boringtoolskit.com/paint-coverage-calculator/
- **Category:** Construction & Measurement
- **Evidence level:** authored-methodology
- **Reviewed:** July 26, 2026
- **Last verified:** 2026-10-12
- **Privacy:** Inputs and results stay in this browser unless the page clearly labels an external request.

## How it works

paintable area = wall area − openings; gallons = coats × area / coverage per gallon

## Worked example

A 12 x 15 ft room, 8 ft walls, 2 doors and 2 windows: 362 sq ft paintable, 724 sq ft with two coats, about 3 gallons at 350 sq ft per gallon.

## Assumptions

- Coverage varies by paint and surface
- Primer may change requirements
- Openings and trim are estimated

## Common questions

### Why does paint coverage vary?

Porous walls, color changes, texture, and paint quality can change actual coverage.

### Should I include a second coat?

For most interior repaints, planning for two coats is safer unless product guidance says otherwise.

## Related tools

- /flooring-calculator/
- /drywall-calculator/
- /construction-estimate-tools/

## Sources

- [Calculation methodology and verification standard](/methodology/)

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