Paint Calculator
Estimate how much paint you need for a room based on wall area, coats, and paint coverage.
How this calculator works
How to use this calculator
Choose metric or imperial units, enter room length, room width, wall height, number of coats, estimated doors/windows area, and paint coverage. Click Calculate Paint Needed.
Formula used
Wall area = 2 × (length + width) × height. Paintable area = wall area − openings. Paint needed = paintable area × coats ÷ coverage. The calculator also recommends adding about 10% extra.
Example calculation
For a 5 m by 4 m room with 2.8 m walls, 2 coats, 4 m² of openings, and 10 m²/L coverage, paint needed is about 9.68 L before extra allowance.
What the result means
The result estimates paint quantity based on area and coverage. Actual usage may vary by wall texture, paint type, primer, color change, and application method.
Frequently asked questions
Should I buy exactly the calculated amount?
Usually no. Buying a little extra helps cover touch-ups and waste.
Does this include ceiling paint?
No. This estimates wall paint only.
What coverage should I use?
Use the coverage listed on your paint can or product page.