Paint Coverage Calculator
Convert square feet to gallons of paint needed, or gallons on hand to the area they'll cover — by surface type and number of coats, with the coverage rate always shown.
What this converter does
This tool converts between an area to paint and the gallons of paint needed, using a coverage rate for the surface type you pick and the number of coats. It also works in reverse: tell it how much paint you have, and it estimates the area you can cover.
How the math works
- Sq ft → gallons: (sq ft × coats) ÷ coverage rate (sq ft per gallon for the surface).
- Gallons → sq ft: (gallons × coverage rate) ÷ coats.
- Recommended purchase: gallons needed, rounded up to a whole gallon can.
Why not just use a generic converter?
There's no fixed unit conversion between area and volume for paint — it depends entirely on how absorbent the surface is and how many coats you're applying. A generic converter can't know that. This tool uses realistic coverage rates for four common surface types and lets you set the number of coats, rather than assuming one number fits every wall.
Worked example
400 sq ft of standard drywall, 2 coats, at 350 sq ft/gallon: (400 × 2) ÷ 350 ≈ 2.29 gallons — buy 3 gallon cans, or one gallon plus a quart, to cover it with room to spare.
Frequently asked questions
How many square feet does a gallon of paint cover?
Typically 350-400 sq ft per coat on smooth, previously painted or primed drywall. Textured, stucco or masonry surfaces cover less per gallon.
How much paint do I need for a 12x12 room?
Roughly 384 sq ft of wall at 8 ft ceilings. At 350 sq ft/gallon and 2 coats, that's about 2.2 gallons — most people buy 3 gallons to be safe.
Do I need 1 or 2 coats of paint?
Two coats is standard for full, even coverage, especially over a different color or bare drywall. One coat can work for touch-ups or high-coverage paint-and-primer products.
How many gallons of paint do I need for a 2,000 sq ft house exterior?
At 350 sq ft/gallon and 2 coats, about 11.4 gallons — round up to whole gallons or quarts when buying.
Limitations
Coverage rates are typical published figures — actual coverage varies by paint brand, color (dark colors and reds often need an extra coat), application method (roller vs. sprayer) and surface porosity. Always check the coverage stated on your specific paint can.
Put this converter on your site
Run a site for suppliers, contractors or DIYers? You can embed the Paint Coverage Calculator as a free widget — responsive, no registration, and nothing added to your page beyond the calculator itself.
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