Paint Calculator
Calculate how much paint you need for any room. Accounts for doors, windows, coats, and container sizes.
How to use the Paint Calculator
- Enter the room length, width and height in feet.
- Enter doors and windows so their area can be deducted.
- Choose the paint type, coats and the coverage printed on the product label.
- Review the result in US gallons and the suggested mix of quarts, one-gallon and five-gallon containers.
Why use this tool
- Calculates wall and ceiling area in square feet.
- Accounts for openings, multiple coats and a practical waste allowance.
- Turns the total volume into common US paint container sizes.
Coverage varies by product, surface texture, application method and color change. Bare drywall, masonry and other porous surfaces may need primer and can use more paint than a sealed smooth surface. Always use the coverage and preparation instructions for the exact product being purchased. Keep enough matching paint for touch-ups and confirm local requirements for storage and disposal.
Part of Builder Tools Calculators — free construction tools for US contractors.