Paint Calculator

Buying the right amount of paint saves money and avoids frustrating mid-project trips to the store. This paint calculator estimates how much paint you need by taking your room dimensions, the number of coats, and subtracting areas covered by doors and windows. The result is an accurate gallon or liter count that accounts for real-world coverage rates.

The calculator uses standard paint coverage of approximately 350 square feet per gallon (about 10 square meters per liter) for smooth surfaces with a roller. You can adjust this rate for textured walls, bare drywall, or other surfaces that absorb more paint. Enter the number of doors and windows to automatically deduct their area from the total, giving you a more precise estimate.

Whether you are painting a single accent wall or an entire house, the tool breaks down the math room by room. It also shows total wall area before and after deductions so you can verify the numbers. For multi-coat jobs, the calculator multiplies appropriately - because a second coat typically uses less paint than the first on primed surfaces, you can optionally adjust the coverage rate per coat.