Paint Cost Calculator – Volume, Can Mix & Total Price
Use this paint cost calculator to turn your room size and coverage into a shopping list with prices. Enter your room dimensions (or a direct paintable area), choose the number of coats, set a realistic coverage rate, and add your local can prices. We calculate total litres/gallons, suggest a can mix to cover it, and provide a materials total with optional tax.
How It Works
- Room mode: wall area =
2 × (Length + Width) × Height − doors − windows, plusLength × Widthif you include the ceiling. - Direct area: enter total paintable m²/ft².
- Volume:
(area × coats) ÷ coverage, then add your overage for touch-ups and roller tray losses. - Can mix: we propose large cans first and top-up with smaller sizes to cover the total; cost is based on the prices you enter.
Coverage Tips
- Smooth, previously painted walls: 10–12 m²/L (≈ 350–400 ft²/gal).
- Raw drywall or porous surfaces may need a primer coat and lower coverage.
- Dramatic color changes usually need an extra coat or a tinted primer.
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Paint Cost Calculator FAQs
How accurate is a paint cost calculator?
Paint estimates are typically accurate when your coverage rate matches your surface. Smooth walls often land around 10–12 m²/L (350–400 ft²/gal), while textured or porous walls can be lower. For the best result, use the product’s label coverage and add 5–15% overage for waste, touch-ups, and cutting-in.
Should I include the ceiling in my paint estimate?
If you’re painting the ceiling, tick Include ceiling in Room mode. Ceilings often absorb more paint due to roller technique and texture, so consider a slightly higher overage or a slightly lower coverage rate if you’re working on a rough ceiling.
Do doors and windows reduce the paint needed?
Yes—openings reduce paintable wall area. This calculator subtracts a default area per door/window, and you can enable Advanced overrides if your openings are larger (e.g., sliding doors or large windows). If you subtract too much and the wall area goes negative, it usually means your opening counts/sizes need adjustment.
Why does the suggested can mix sometimes leave leftover paint?
Paint is sold in fixed sizes, so the closest mix can slightly exceed your required volume. Leftover is usually helpful for touch-ups and future repairs. If you want to reduce leftover, try entering prices for smaller sizes so the calculator can top-up more precisely.
Accuracy & Review
Reviewed by: Natalie Green
Natalie reviews our paint-related calculators, validating coverage rates, coat count assumptions, and product yield calculations. She focuses on ensuring estimates align with real-world application results across interior and exterior projects.
Last updated:
See: Methodology · Data Sources · Review Board
Important Estimate Disclaimer
Results are provided for general planning and budgeting purposes only. Actual coverage may vary based on surface condition, layout complexity, waste allowance, and product specifications.
Refer to our Methodology and Data Sources for calculation assumptions.
Surface preparation, substrate irregularities, and installation methods may increase required material quantities.