Paint planning guide

How Much Paint Do I Need?

For a rectangular room, calculate wall area from the room perimeter and wall height, then multiply by the number of coats and divide by the paint's stated coverage. The chart below assumes 8-foot walls and 350 ft² per gallon before deducting doors and windows.

Paint gallons by room size

Room sizeWall area1 coat2 coats
8 × 10 ft288 ft²0.82 gal1.65 gal
10 × 10 ft320 ft²0.91 gal1.83 gal
10 × 12 ft352 ft²1.01 gal2.01 gal
12 × 12 ft384 ft²1.10 gal2.19 gal
12 × 14 ft416 ft²1.19 gal2.38 gal
12 × 16 ft448 ft²1.28 gal2.56 gal
14 × 16 ft480 ft²1.37 gal2.74 gal
15 × 20 ft560 ft²1.60 gal3.20 gal
20 × 20 ft640 ft²1.83 gal3.66 gal

Table values are theoretical coverage before openings, waste or touch-up allowance. Actual paint coverage varies by product, surface texture, color change and application.

Example: 12 × 12 room

A 12 × 12 ft room with 8 ft walls has 384 ft² of gross wall area. At 350 ft² per gallon, one coat requires about 1.10 gallons before deducting openings. Two coats require about 2.19 gallons.

Calculate the actual room

Enter room dimensions, doors, windows, coats, product coverage and touch-up allowance.

Open Paint Calculator →

Why the can count can exceed the exact gallons

Paint is purchased in fixed container sizes. A calculated requirement of 2.2 gallons cannot normally be purchased as exactly 2.2 gallons, so your shopping quantity must account for available can sizes and any paint you want to retain for future touch-ups.

For drywall and wallpaper quantities, visit the Walls & Finishes Planning Hub.