Paint Coverage Converter

Paint coverage depends on the paint type and surface texture.

Typical coverage rates:

Those two columns are the same numbers, and that is the point. One sq m per liter is 40.75 sq ft per gallon, so 10 sq m/L is 407 sq ft/gal, not the 350-400 you will see quoted on a US can. That gap is real but it is not arithmetic. US and European manufacturers test and label to different conventions, and the American figure is generally the more cautious of the two. If you are working from a can in your hand, use the number printed on it and put that in the calculator rather than any table.

The formula:

• Paint needed (liters) = Area (sq m) ÷ Coverage rate (sq m/L) × Coats
• Paint needed (gallons) = Area (sq ft) ÷ Coverage rate (sq ft/gal) × Coats

Unit conversions:

• 1 gallon (US) = 3.785 liters
• 1 sq meter = 10.764 sq feet
• 1 sq m per liter = 40.75 sq ft per gallon
• 1 liter covers about 10 sq m = 107.6 sq ft (at standard rate)

Standard door and window sizes, which is what the calculator subtracts:

• Interior door: 0.8 × 2.0 m = 1.6 sq m (17.2 sq ft)
• Average window: 1.2 × 1.2 m = 1.44 sq m (15.5 sq ft)

Tips:

• Most walls need 2 coats for good coverage.
• Dark-to-light color changes may need 3 coats.
• Textured surfaces use 20-30% more paint.
• Always buy 10% extra for touch-ups and waste.

The coverage rates on a paint can are best-case numbers, measured on smooth, sealed, primed drywall. Real walls drink more. Bare drywall, fresh patches, and porous masonry soak up the first coat, so your true first-coat coverage can run 20 to 30% below the label, which is exactly why the calculator multiplies by your coat count rather than trusting one pass to cover.

Two things decide how many coats you actually need. Color is the obvious one: going from a dark wall to a pale one, or laying down a saturated red or yellow, often takes three coats because those pigments are translucent. The quieter factor is paint quality. Cheap paint carries less pigment and fewer solids, so it covers thin and you end up applying more of it, which is how a “bargain” gallon becomes the expensive option. When you finish, keep a labeled jar of leftover from each room. Touch-ups months later never match a freshly bought can, even of the identical color, because the wall has faded a little and the new batch is mixed fresh.