🎨 The Paint Calculation Formula
Calculating paint is simple with the right formula. You need three pieces of data: the area to paint, your paint's coverage rate, and the number of coats.
Liters = (Area m² × Number of Coats) ÷ Coverage (m²/L)
Measure Each Wall
Measure length × height of each wall. Add all areas. Subtract doors (~1.9 m²) and windows (~1.5 m²).
Add the Ceiling (if painting it)
Ceiling area = Room length × Room width. Add this to your total if you're also painting the ceiling.
Check the Coverage
Check the can label for coverage rate (m²/L). Typical interior latex covers 10-12 m²/L.
Calculate and Round Up
Apply the formula, then round up to the nearest can size. Always buy a bit extra — you'll need it for touch-ups.
📋 Coverage by Paint Type
| Paint Type | Coverage (m²/L) | Recommended Coats | Best For |
|---|---|---|---|
| Interior Latex (Matte) | 10-12 | 2 | Bedrooms, living rooms |
| Interior Satin | 12-14 | 2 | Hallways, children's rooms |
| Semi-Gloss | 12-14 | 2 | Kitchens, bathrooms, trim |
| Ceiling Paint | 8-10 | 2 | Ceilings (anti-drip formula) |
| Exterior Latex | 8-10 | 2-3 | Exterior walls, facades |
| Primer/Sealer | 8-10 | 1 | New surfaces, stain blocking |
| Enamel (Oil-based) | 14-16 | 2 | Doors, windows, metal |
| Textured | 3-5 | 1 | Decorative walls, ceilings |
🪣 Can Sizes
Paint comes in standard sizes. Choose the most convenient combination:
| Can | Volume | Covers (approx.) | Ideal For |
|---|---|---|---|
| Small | 1 L | 10-12 m² | Touch-ups, accents |
| Quart | 4 L | 40-48 m² | One wall of a room |
| Gallon | 20 L | 200-240 m² | Multiple rooms, full house |
💡 Pro Tips for Better Results
Even cans of the same color can vary slightly between batches. Pour all into a large bucket and mix before painting for perfectly consistent color.
Apply paint in a "W" pattern for even distribution, then fill in with parallel strokes. This prevents streaks and roller marks.
Rough or textured walls (stucco, brick, textured ceiling) can absorb 20-30% more paint. Increase your estimate. Always apply primer first on porous surfaces.
📊 Real-World Example
Wall area: 2 × (5 + 4) × 2.5 = 45 m²
Less openings: 1 door (1.9 m²) + 2 windows (3.0 m²) = 4.9 m²
Paintable area: 45 - 4.9 = 40.1 m²
Ceiling: 5 × 4 = 20 m²
Total area: 40.1 + 20 = 60.1 m²
Using interior latex (10 m²/L), 2 coats:
Paint needed: (60.1 × 2) ÷ 10 = 12.02 L
Cans to buy: 3 × 4L cans (12L) + keep 0.5L for touch-ups
🧮 Calculate Paint Automatically
Our calculator supports 8 paint types, 3 can sizes, and multiple surfaces. Add rooms, set coats, and get exact quantities.
🎨 Try the Paint Calculator — Free❓ Frequently Asked Questions
Typically 2 coats for the same color or lighter shades. Use 3 coats when covering dark colors with light ones. One coat only for touch-ups with the same paint.
Yes, primer is recommended for: new drywall, bare wood, stains/water damage, dramatic color changes, and glossy surfaces.
Latex (water-based): Easy cleanup, low odor, fast drying. Best for walls and ceilings. Oil-based: More durable, smoother finish, better adhesion. Best for trim and doors.
Subtract door and window areas from the total area. Standard door: ~1.9 m². Standard window: ~1.5 m².
Yes. Matte covers 10-12 m²/L. Semi-gloss 12-14 m²/L. High gloss 14-16 m²/L. Textured surfaces require 20-30% more paint.
