Paint Coverage Per Gallon by Surface Type
| Surface Type | Coverage Per Gallon | Notes |
|---|---|---|
| Smooth interior walls | 350–400 sq ft | Standard coverage |
| Lightly textured walls | 300–350 sq ft | Orange peel texture |
| Heavy knockdown/popcorn | 200–250 sq ft | Rough texture absorbs more |
| New/bare drywall | 250–300 sq ft | Primer recommended |
| Exterior smooth siding | 300–400 sq ft | Good surface condition |
| Brick (unpainted) | 100–150 sq ft | Very high absorption |
| Stucco | 100–200 sq ft | Highly porous |
Why Coverage Varies So Much
The stated coverage rate on a paint tin (typically 400 sq ft per gallon) is calculated on a smooth, previously painted surface under ideal conditions. Real-world coverage is almost always lower because of surface texture, porosity, application method, and the skill of the painter.
A brush applies paint less efficiently than a roller — using a brush throughout rather than a roller on large areas can reduce effective coverage by 15–20%. An airless sprayer, when set up correctly, can match or slightly exceed roller coverage but generates significant overspray waste.
How Much Does a Litre of Paint Cover?
In metric measurements, a litre of standard interior paint covers approximately 9 to 11 square metres per coat (95 to 118 sq ft). A 5 litre tin covers approximately 45 to 55 square metres — roughly the walls of an average 12×14 bedroom with 8ft ceilings.
UK and European paint tins are labelled in litres. Use the calculator above to get precise estimates in both litres and gallons for any room size.
Related Paint Calculators
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Frequently Asked Questions
How many square feet does a gallon of paint cover?
A gallon of standard interior paint covers 350 to 400 square feet on smooth walls per coat. Coverage is lower on textured walls, bare drywall, or porous surfaces.
How much does a gallon of exterior paint cover?
Exterior paint covers 300 to 400 sq ft per gallon on smooth siding. Rough surfaces like stucco and brick absorb significantly more — only 100–200 sq ft per gallon.
How much does a quart of paint cover?
A quart (0.25 gallon) covers approximately 87 to 100 square feet — about one wall of an average room. Quarts are ideal for accent walls, trim, or small spaces.
Does paint quality affect coverage?
Yes — premium paints contain more pigment and binder and typically cover 400–450 sq ft per gallon. Budget paints often cover only 300–350 sq ft per gallon.
How much does a litre of paint cover?
A litre of standard interior paint covers 9 to 11 square metres (95 to 118 sq ft) per coat on smooth walls.
Why does my paint not cover as much as the tin says?
Tin coverage rates are measured on smooth, previously painted surfaces under ideal lab conditions. Real coverage is lower due to surface texture, porosity, application technique, and waste.