Paint calculator
Enter the room size, the doors, the windows and the number of coats. The calculator takes out the openings and tells you how much paint to buy, in gallons or liters.
See your design as an AI render — freeEach door takes out 20 sq ft and each window 15 sq ft (standard sizes).
- Area to paint
- 334 sq ft
- Exact amount
- 1.91 gal
- Walls
- 334 sq ft
Use the coverage printed on the can: it changes with the brand, the color and the surface. New or very porous walls may need an extra coat.
See the room in the new color
Upload a photo of the room and RendScene returns a render with the finish and colors you pick, before you open the can.
5 free renders · no credit card
How to calculate paint
Start from the wall area, take out the openings and divide by the paint's coverage.
- 1
Work out the wall area
Perimeter × height. A 12 × 12 ft room with 8 ft walls has 2 × (12 + 12) × 8 = 384 sq ft of wall.
- 2
Take out doors and windows
One 20 sq ft door and two 15 sq ft windows come off: 384 − 20 − 30 = 334 sq ft.
- 3
Multiply by coats, divide by coverage
With 2 coats and 350 sq ft per gallon: 334 × 2 ÷ 350 = 1.91 gallons.
- 4
Round up
Buy at least 2 gallons. In the store, pick the can sizes that add up to that with the least left over.
Paint for common rooms
Walls without openings taken out, 2 coats, at the calculator's example coverage.
| Room (8 ft walls) | Wall area | 2 coats at 350 sq ft/gal |
|---|---|---|
| 10 × 10 ft | 320 sq ft | 1.83 gal |
| 12 × 12 ft | 384 sq ft | 2.19 gal |
| 14 × 12 ft | 416 sq ft | 2.38 gal |
| 16 × 14 ft | 480 sq ft | 2.74 gal |
Frequently asked questions
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From drawing to render in minutes
Upload a floor plan, a sketch or a screenshot of your 3D model and get a photorealistic image that stays faithful to what you drew.
No credit card required