How to use it
A better estimate in three steps.
- 01
Enter the room dimensions and subtract openings.
- 02
Set coats and the coverage printed on your paint can.
- 03
Compare waste allowances before buying.
Home & DIY
Paint Calculator
Estimate wall area, paint volume, can count, and total paint cost—with doors, windows, coats, and waste included.
01
Enter your details
Results update instantly as you type.
Core formula
The math behind the result.
Paint needed = (net wall area × coats × (1 + waste rate)) ÷ paint coverageQuestions
Useful before you decide.
How much extra paint should I buy?
A 10% allowance is a practical starting point for normal walls. Detailed trim, textured surfaces, repairs, and strong color changes may require more.
Does this include the ceiling?
Not automatically. Add the ceiling as a separate rectangular surface or include its area by increasing the calculated paintable area.
Why can the can count look high?
The calculator rounds up to whole cans so the estimate reflects what can actually be purchased.