Paint Calculator

Buying too little paint means an extra trip mid-job. Buying too much wastes money. This calculator helps you buy the right amount the first time, with an optional 10% buffer for touch-ups and uneven surfaces.

• Room repainting: Estimate paint for a bedroom or living room before heading to the store.
• Exterior painting: Scale up for whole-house exterior calculations using total facade area.
• Contractor estimates: Quickly prepare material lists for painting quotes.
• Feature walls: Calculate a single accent wall with a different color from the rest of the room.

1. 1Measure the total paintable area in square meters (subtract windows and doors if desired).
2. 2Enter the number of coats. Two coats gives good coverage; use three for dark colors or porous surfaces.
3. 3Enter the coverage rate from your paint tin (typically 8–12 m²/L).
4. 4The calculator multiplies area by coats, then divides by coverage to get liters.
5. 5Results shown in liters and gallons, with a 10% waste buffer.

• Using the wrong coverage rate: Manufacturers publish coverage rates assuming a smooth, primed surface. Rough or textured walls, bare drywall, or deep colors require more paint. Use the lower end of the stated coverage range and add extra for these cases.
• Forgetting to subtract doors and windows: A room's total wall area includes the door and window openings. Subtract those areas (roughly 1.5-2 m² per door, 0.8-1.5 m² per window) for a more accurate paint quantity.
• Buying exactly the calculated amount: Always buy slightly more than the calculated volume. Touch-ups later use the same batch number; a different batch may not match exactly. Keep at least one extra can of the same batch for repairs.
• Assuming one coat is enough for a colour change: Going from white to dark blue, or dark to light, almost always requires two coats. Priming the surface first reduces the number of topcoats needed for full coverage.

• Measure ceiling and walls separately: Ceiling paint and wall paint are often different products with different coverage rates. Run the calculator twice: once for walls and once for the ceiling.
• Check the tin before buying multiple cans: Buy all cans for a room from the same batch number. Batch numbers appear on the label. Even the same color from different batches can vary slightly, especially for custom mixes.
• Plan your coats around drying time: Most water-based paints are ready for a second coat in 2-4 hours. Oil-based paints need 6-24 hours. Check the manufacturer's recoat time before planning your day.
• Use the liters-per-coat view for budgeting: Divide the total by number of coats to find how much you need per coat. This helps when working in stages or deciding whether you have enough of an existing tin to finish the first coat.