CostBuildrPaint Coverage Per Square Foot Guide
Paint coverage—measured in square feet per liter or per gallon—determines how much paint you need to buy. Coverage varies by paint type, surface texture, and application method. This guide provides realistic coverage numbers for all common scenarios in residential construction.
Coverage Rates by Paint Type
Interior emulsion (water-based): 90–110 sq ft per liter (350–420 sq ft per gallon) per coat. Exterior weather-shield paint: 70–90 sq ft per liter per coat due to thicker film. Primer/sealer: 100–130 sq ft per liter per coat. Enamel (oil-based, for doors/grills): 120–150 sq ft per liter per coat due to thinner application.
Distemper (economy interior): 100–120 sq ft per liter per coat—cheapest option but least durable, suitable for ceilings and utility areas. Texture paint: 25–40 sq ft per liter because it's applied in a very thick film. Always check the manufacturer's coverage specification on the can, as formulations vary between brands.
How Surface Condition Affects Coverage
Smooth, sealed surfaces (previously painted, well-primed new plaster) achieve the high end of coverage ranges. Rough, porous surfaces (unprimed new plaster, cement render, exposed brick) can reduce coverage by 20–30% as the paint soaks into the surface.
Two coats are the minimum for uniform color and adequate film thickness. A third coat is needed when painting a light color over dark, or for deep saturated colors (reds, dark blues) that have inherently low opacity. Sanding between coats on enamel work improves adhesion but doesn't significantly affect coverage.
Calculating Paint Quantity from Coverage
Formula: Liters needed = (paintable area in sq ft × number of coats) ÷ coverage per liter. For a 1,000 sq ft house interior (walls + ceilings) with 2 coats of emulsion at 100 sq ft/liter: 1,000 × 2 ÷ 100 = 20 liters = 5 gallons. Add primer at 1 coat: 1,000 ÷ 115 = 8.7 liters ≈ 9 liters.
Buy in the most economical container size—20-liter buckets are typically 15–20% cheaper per liter than 4-liter cans. Mix all buckets of the same color together in a larger container before painting to ensure uniform color, since even the same batch can have slight shade differences between cans.
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How many square feet does 1 liter of paint cover?
Standard interior emulsion covers 90–110 sq ft per liter per coat on smooth walls. Exterior paint covers 70–90 sq ft per liter. Primer covers 100–130 sq ft per liter. These are per-coat figures; multiply by number of coats for total consumption.
How many coats of paint do I need?
Minimum 2 coats for uniform coverage. Add 1 coat of primer if the surface is new plaster, previously unpainted, or you're making a major color change. Some deep colors (red, yellow, dark blue) may need 3 topcoats.
Is expensive paint worth it?
Premium paints have higher pigment content (better coverage in fewer coats), better washability, and longer life (8–10 years vs 3–5 for economy paints). Over a 10-year cycle, premium paint is often cheaper per year due to less frequent repainting.