Paint coverage is the wall area one gallon covers in one coat, measured in square feet per gallon. The headline number everyone uses — 350 sq ft per gallon — is the rule of thumb for standard interior latex on previously painted walls. But primer, exterior paint, semi-gloss, and textured finishes all live in different bands, and using the wrong rate is the most common reason paint estimates come up short. Every rate below is sourced; the per-texture splits are labeled estimates.
Coverage table by paint type
| Paint type | Coverage (sq ft/gal) | Source |
|---|---|---|
| Interior flat latex | 350–400 | Sherwin-Williams Duration Home Interior Latex product data sheet |
| Interior eggshell / satin latex | 350–400 | Sherwin-Williams Duration Home Interior Latex product data sheet |
| Interior semi-gloss | ~300–350 | cypaint.com coverage guide |
| Primer (new drywall) | 300–400 | KILZ PVA Drywall Primer technical data sheet |
| Primer (rough surfaces) | 200–300 | KILZ technical data sheet |
| Exterior siding paint | 250–350 | cypaint.com coverage guide |
| Exterior, smooth siding (estimate) | ~350 | Estimate from the cypaint.com 250–350 range |
| Exterior, textured siding (estimate) | ~300 | Estimate from the cypaint.com 250–350 range |
| Exterior, brick / stucco (estimate) | ~250 | Estimate from the cypaint.com 250–350 range |
| Textured finishes | 150–250 | cypaint.com coverage guide |
What the coverage number assumes
Every figure in the table is a per-coat rate on a properly prepared surface. Two coats doubles the paint — the 350 figure does not mean one gallon does 700 sq ft of wall. And “properly prepared” is doing real work in that sentence: the manufacturer rates are measured on smooth, sealed panels. Anything that deviates from that panel pulls your actual coverage down.
Four factors that change your real coverage
1. Porosity of the surface
New drywall, bare wood, and fresh plaster are thirsty — they soak the first coat into the surface instead of leaving it as a film. That is why the KILZ technical data sheet drops from 300-400 sq ft/gal on drywall to 200-300 on rough surfaces. A coat of primer seals the surface so the finish coats behave closer to the label rate, which is why primer pays for itself on new drywall.
2. Texture
Texture adds surface area the square-footage math doesn't see. A popcorn ceiling can use about 25% more paint than a flat one (estimate), and heavily textured finishes sit at 150-250 sq ft/gal per cypaint.com — roughly half of smooth latex. Light orange-peel or knockdown texture falls in between; budget the extra 25% and you will rarely be caught short.
3. Application method
Brushes, rollers, and sprayers all hit the label rate differently in practice. Sprayers are fastest but lose paint to overspray and tend to lay a thinner film per pass, so large spray jobs often need an extra pass to build full coverage. Rollers are the middle ground most DIY estimates assume. There is no universal multiplier — check the product data sheet and, for big jobs, do a test section and measure what you actually used.
4. Color change
Coverage rates assume the new color can hide the old one in the stated number of coats. A drastic dark-to-light change breaks that assumption: the old color ghosts through, and you end up needing primer plus a full extra finish coat. The paint quantity math stays the same — you just run it with an extra coat, which is exactly what our interior paint calculator lets you do.
How to read a product data sheet
The coverage table above gives you planning figures, but the authoritative number for the exact can in your hand is always the manufacturer's product data sheet (PDS) or technical data sheet (TDS) — usually a PDF on the brand's website. Here's what to look for:
- Spread rate / coverage: given as a range (e.g. 350-400 sq ft/gal). Plan with the bottom of the range.
- Recommended film thickness: sometimes listed in mils (thousandths of an inch) wet and dry. The coverage rate assumes you apply the paint this thick — thin it or stretch it and coverage per coat drops.
- Surface preparation: the data sheet states what the rate assumes (e.g. previously painted, primed, or sealed surfaces). New drywall or bare wood without primer won't hit the printed number.
- Recoat window: how long to wait between coats. It doesn't change the quantity, but rushing it ruins the first coat's film and wastes paint.
Why two brands' “350” aren't equal
Two paints can both claim 350 sq ft/gal yet behave differently on your wall. The printed spread rate is about area covered, not about hide — how well one coat obscures what's underneath. Hide comes from pigment and solids content, which is why premium paints ($55-85/gal in 2026) typically cover a color change in two coats while budget paints ($20-30/gal) need three. The data sheet sometimes lists “solids by volume” — higher generally means better hide and a thicker dry film per coat.
Practical takeaway: when comparing two paints at the same spread rate, the one with better hide needs fewer coats, and coats — not the per-gallon rate — are what determine your total gallons. That's also why the cheapest gallon is rarely the cheapest project, as our 2026 cost breakdown shows.
How to use these numbers
The formula is always the same: (area × coats) ÷ coverage per gallon, rounded up to the nearest quarter gallon. Pick the coverage rate for your surface from the table — 350 for standard interior walls, 300 for new drywall primer, 250 for brick — and run the math. Worked examples: a 12x12 room, a 2,000 sq ft house exterior, and a room measured from scratch in our measuring guide.
Frequently asked questions
Label coverage rates are measured on smooth, sealed test panels under ideal conditions. Real walls are porous, textured, or previously unpainted, and rollers and sprayers apply paint at different film thicknesses — all of which pull real-world coverage below the printed number. This is why estimators use 350 square feet per gallon instead of the top of the 350-400 range.
Roughly. The KILZ PVA Drywall Primer technical data sheet lists 300-400 square feet per gallon on new drywall, and 200-300 square feet per gallon on rough surfaces — essentially the same band as finish paint, slightly lower on porous or rough material.
Sprayers lay paint down fast but lose some to overspray, and they tend to apply a thinner film per pass, so you may need an extra pass to build the same coverage a roller gives in one. Treat the coverage table as a planning figure either way and check the product data sheet for the specific product.
Heavily textured finishes are listed at 150-250 square feet per gallon by cypaint.com — roughly half the coverage of smooth interior latex. Even light orange-peel or knockdown texture on otherwise normal walls adds about 25% more paint usage (estimate).
Related
- Interior paint calculator — plug in your room and get gallons instantly.
- Exterior paint calculator — uses the exterior coverage rates from this table.
- How many coats of paint do walls need? — because coverage is per coat.
- 7 paint quantity mistakes that waste money — the classic ways these rates get misapplied.