Construction tools
Paint Calculator
Estimate paint quantity from room dimensions or known area, coats, and product-label coverage.
Paint estimate
Use the coverage printed for the paint you selected. Coverage and actual use vary by product, surface, and application.
How this estimate works
The calculator uses paint quantity = paintable area × coats ÷ label coverage. It calculates paintable area, applies the number of coats, then divides by the coverage printed for your selected product.
For example, 320 sq ft of walls painted with two coats at 350 sq ft per gallon needs about 1.83 gallons, which rounds up to two whole gallons. This is an estimate, not a product or application specification.
Before you buy
Use the coverage printed on the product label or technical data sheet. Actual coverage can differ with surface texture, condition, application method, and the number of coats needed.
This calculator does not choose a paint product, primer, finish, preparation method, or waste allowance. Follow the selected product's label and local safety guidance.
Method & sources
Dimensions are normalized to metres and areas to square metres before display conversion. Gallons are calculated from the entered US-gallon label coverage; display values are rounded only for readability.
Important limits
- This estimates a rectangular room or a known paintable area; it does not model exterior elevations, trim, doors, complex ceilings, or multiple rooms.
- It does not select paint, primer, sheen, preparation steps, waste allowance, price, or safety measures.
- Results depend on the coverage and container size entered by the visitor and are not a supplier quote or product-performance guarantee.
Reviewed references
- Sherwin-Williams: How to Use Paint Calculator
Reviewed 2026-07-21. Explains estimating coated area and checking selected-product coverage. It notes that texture and application conditions can affect actual paint use.
- Benjamin Moore: Regal Select Waterborne Interior Paint
Reviewed 2026-07-21. Provides one product-specific coverage example, demonstrating why users should use their selected product label rather than a universal coverage claim.
- Inch Calculator: Paint Calculator
Reviewed 2026-07-21. Competitive research only: informed the area, coats, and coverage task flow. It is not used as a paint-product or application specification.