Paint Coverage Calculator
Trending
Paint Coverage Calculator
Calculate paint needed for your room project.
Last updated: August 11, 2026
Paint Coverage Calculator: Never Run Out or Overbuy
Calculate exactly how much paint you need — for walls, ceilings, doors, trim — in liters or gallons. Accounts for coats, surface type, and waste. Save money and time on your DIY project.
Example: 12m² wall, 2 coats = ~2.4L | 300 ft² room = ~0.8 gal (2 coats).
Standard Paint Coverage per Liter/Gallon
| Surface Type | m² per Liter | ft² per Gallon |
|---|---|---|
| Smooth drywall (primed) | 10–12 | 400–450 |
| Rough plaster / brick | 6–8 | 250–300 |
| Wood siding | 8–10 | 300–350 |
| Ceiling (textured) | 8–10 | 300–350 |
| Doors & trim | 12–15 | 450–500 |
Rule of Thumb: 1 liter covers ~10 m² (1 coat) on smooth walls. Always buy 10% extra for waste.
How to Measure & Calculate
- Measure walls: Height × Width per wall (skip windows/doors or subtract later)
- Ceiling: Length × Width
- Subtract openings: Door (~2 m²), Window (~1–2 m² each)
- Choose coats: 1 for refresh, 2 for color change or new drywall
- Enter values → get exact liters/gallons
Real Project Examples
Bedroom (3m × 4m × 2.5m)
Walls: 35 m² | 2 coats | Smooth = 7 liters
Living Room + 2 Doors
Walls: 50 m² - 4 m² doors = 46 m² | 2 coats = 9.2 liters
Pro Painting Tips
Save Paint
- Prime bare drywall (+20% coverage)
- Use quality roller (less splatter)
- Stir well, don’t thin unless needed
Avoid Mistakes
- Don’t forget ceiling!
- Dark colors need 3 coats
- Buy all cans from same batch
Why Trust This Calculator?
Accuracy: Based on ISO 6504 & paint manufacturer data (Sherwin-Williams, Dulux, Benjamin Moore).
Privacy: No data stored. Results vanish instantly.
Updated: Nov 2025 with real-world coverage rates.
Frequently Asked Questions
A standard 10×10 ft room with 9 ft ceilings has about 320-340 sq ft of wall area. With 2 coats on smooth walls at 350 sq ft/gallon coverage, that works out to roughly 0.8-1 gallon of paint, before subtracting doors and windows.
Yes, if you're painting bare drywall, covering stains, or making a dramatic dark-to-light color change. Primer counts as one coat — plan for 1 coat of primer plus 2 finish coats in those cases. Skip it for a simple refresh coat over existing paint in similar color.
Usually 1-2 coats. Textured ceilings absorb more paint and have lower effective coverage per gallon than smooth walls, so budget extra when calculating ceiling paint.
It's not recommended. Color and finish can vary subtly between brands and even between production batches of the same brand. Buy all the paint for one project from the same batch, or have your paint store "box" (mix together) multiple cans to even out any variation.
A standard interior door is about 21 sq ft (3ft × 7ft) and a standard window is about 15 sq ft (3ft × 5ft). Subtract these from your total wall area before calculating paint needed — this calculator does that automatically based on how many doors and windows you enter.
Dark and saturated colors have less hiding power per coat than lighter, more opaque colors, especially when covering a lighter existing color. Plan for 3 coats when going dramatically darker, or use a tinted primer matched closer to your final color to reduce the number of finish coats needed.
Yes — buy 10-15% extra paint beyond the calculated amount. This covers touch-ups, small application errors, and future repairs, and ensures you don't run out mid-wall and have to pause for a paint store run with mismatched drying time between sections.
Significantly. Rough plaster, brick, or heavily textured surfaces can need 30-40% more paint than smooth drywall because of the increased surface area and paint absorption. Adjust the coverage-per-gallon field down (e.g., to 250-300 sq ft) for rough or textured surfaces.
It's based on standard industry coverage rates (per ISO 6504 and major paint manufacturer specifications like Sherwin-Williams, Dulux, and Benjamin Moore), typically 350-400 sq ft per gallon for smooth walls. Actual coverage varies by paint brand, surface porosity, and application method, so treat the result as a solid planning estimate rather than an exact figure.
Yes — once the page has loaded, all calculations run entirely in your browser with JavaScript, with no server round-trip required, so it continues working even without an internet connection.