paint
Paint coverage
Calculate wall area minus openings with coats and country coverage defaults.
Results are approximate. Verify with manufacturer specifications or consult a professional.
Project inputs
IMPERIAL
Enter a value in ft.
Enter a value in ft.
Enter a value in ft².
Enter a value in Your units.
Enter a value in ft²/gal.
Includes breakage, spillage, onsite adjustments
Material output
Updates instantly as you type.
Primary output
853.9m²
853.9 m²
≈ 798 m² primary output
Paint volume
Your units
4.51 gal
Results are approximate. Verify with manufacturer specifications or consult a professional.
How it works
Frequently asked questions
Country defaults
United States · USD · imperial
Waste factor: 7.0%
Context & guidance
Results are approximate. Verify with manufacturer specifications or consult a professional.
About This Calculator
Calculate the exact amount of paint needed for interior or exterior walls, accounting for room perimeter, wall height, door and window openings, number of coats, and country-specific coverage rates. Coverage varies by paint type: latex typically covers 8-12 m²/L (320-480 ft²/gal), while oil-based paints cover 6-10 m²/L (240-400 ft²/gal). The calculator automatically applies waste factors based on your country's standards.
Step-by-Step Instructions
Measure Room Perimeter
Add up all wall lengths in the room. For a rectangular room: Perimeter = 2 × (Length + Width). For L-shaped or irregular rooms, measure each wall segment separately and sum them. Typical residential rooms have perimeters of 12-30m (40-100ft).
Enter Wall Height
Measure from floor to ceiling. Standard ceiling heights are 2.4-2.7m (8-9ft) in most countries, but can range from 2.1m (7ft) in older homes to 3m+ (10ft+) in modern construction. Measure at multiple points and use the average if heights vary.
Subtract Openings
Calculate the area of all doors and windows. Standard door: 2.0m² (21ft²), single window: 1.5-2.5m² (16-27ft²), double window: 3-4m² (32-43ft²). For multiple openings, sum their areas. The calculator subtracts this from total wall area automatically.
Select Number of Coats
Most interior walls need 2 coats for even coverage and color depth. Dark colors or color changes may require 3 coats. Exterior surfaces typically need 2-3 coats depending on substrate condition. Primer counts as a separate coat if using a different product.
Check Coverage Rate
Coverage is automatically set based on your country's defaults (typically 8-12 m²/L for latex). Premium paints often have higher coverage (10-14 m²/L), while budget paints may cover less (6-9 m²/L). Check your paint can label for exact coverage.
Calculate and Order
The calculator shows total paintable area, paint volume needed, and estimated packaging (cans/buckets). Always round up to the nearest full container. For example, if you need 8.2L, order 9L (or two 5L cans) to ensure you have enough for touch-ups.
Common Mistakes
Forgetting to subtract openings
Doors and windows can account for 10-20% of wall area. Not subtracting them leads to 10-20% over-ordering, which wastes money. Always measure and subtract all openings accurately.
Underestimating coats needed
One coat is rarely sufficient, even with high-quality paint. Budget for 2 coats minimum. Dark colors, color changes, and porous surfaces (like new drywall) often need 3 coats for proper coverage.
Using wrong coverage rate
Coverage varies significantly by paint type and quality. Premium paints (10-14 m²/L) cover more than budget paints (6-9 m²/L). Always check the paint can label and adjust the calculator if needed.
Not accounting for texture and surface condition
Textured walls (popcorn, stucco) require 20-30% more paint than smooth walls. Rough or porous surfaces (new drywall, unpainted masonry) absorb more paint. Add 15-25% extra for these conditions.
Pro Tips
Buy 10-15% extra paint for touch-ups and future repairs. Store leftover paint in sealed containers labeled with room and color code.
For color changes (especially dark to light), budget for 3 coats. Primer helps but doesn't eliminate the need for extra coats.
Textured surfaces (popcorn ceilings, stucco) require 20-30% more paint. Measure texture depth and adjust accordingly.
Exterior paint typically needs higher coverage rates (10-12 m²/L) due to thicker formulations, but check your specific product.
For trim and doors, calculate separately: they often need different paint types (semi-gloss or gloss) and have different coverage rates.
Keep paint from the same batch for consistency. Mix multiple cans together if you need more than one container (boxing).