Paint Coverage Calculator
Enter wall height, width, paint coverage per gallon, and number of coats to estimate exactly how much paint to buy.
Also handy: Fence Material Calculator, Deck Material Calculator
Calculate paint needed
Enter the wall dimensions, paint coverage rate, and number of coats. This tool estimates the amount of paint required for a simple rectangular wall.
0.27 gallons
Based on a wall height of 8 ft, wall width of 12 ft, 1 coat, and coverage of 350 sq ft per gallon.
How to use this calculator
Enter the wall height and width in feet, then enter the paint coverage shown on your paint can. Add the number of coats you expect to apply. The calculator multiplies the wall area by the number of coats and then divides by the coverage rate to estimate gallons required.
Tips for success
- Always round up when buying paint. Running short mid-wall is far more disruptive than having a little leftover.
- Rough and porous surfaces absorb more. Add 10–15% to your estimate for textured drywall, brick, or bare wood.
- Dark-to-light changes need two coats. Going from a dark color to a light one almost always requires a second coat and possibly a tinted primer.
- Check the label, not just a rule of thumb. Paint can coverage varies significantly by brand, sheen level, and surface type.
- Keep some paint for touch-ups. A quart stored in a cool, dry place can save you from repainting a whole wall later.
Common mistakes
- Skipping the second coat. Many paints require two coats for full color coverage, especially over new drywall or dark colors.
- Using a guessed coverage number. Actual coverage varies by 50+ sq ft per gallon between brands. Always read the product label.
- Not rounding up. Buying the exact calculated amount leaves no margin for edges, cut-ins, and light spots.
- Ignoring surface texture. Rough surfaces absorb significantly more paint than smooth ones.
- Measuring incorrectly. Double-check your height and width. An error of 1 foot on a wide wall changes the result by a full gallon.
FAQ
Does this subtract doors and windows?
No. This version uses the full wall area. Subtract doors and windows manually if you want a more exact result.
Does this support more than one coat?
Yes. Enter the number of coats you expect to apply.
What is a typical paint coverage rate?
Many paints cover roughly 300 to 400 square feet per gallon, but always check the product label.
Should I buy extra paint?
Usually yes. A little extra helps with touch-ups, edges, mistakes, and future repairs.
Can I use this for ceilings?
Yes. The same area calculation works for ceilings as long as you enter the correct dimensions and paint coverage.