Home Project Calculator

Paint Calculator

Estimate how much paint you need for a room, ceiling, accent wall, or exact wall area, including coats, doors, windows, paint coverage, waste, and cost.

Use this paint calculator before buying paint for a bedroom, living room, hallway, nursery, bathroom, kitchen, ceiling, or accent wall. Enter the room size or exact square footage, choose the number of coats, subtract openings, and estimate the amount of paint to buy.

Interior Paint Estimator

Calculate paint needed

Estimate gallons based on room size or exact wall area, openings, ceiling option, number of coats, coverage per gallon, waste, and cost.

Paint Tips

1. Project size

Full room Exact wall area

Room length feet Room width feet Wall height feet

Include ceiling area

2. Openings and coats

Doors count Average door width feet Average door height feet Windows count Average window width feet Average window height feet Other area to subtract sq ft Number of coats recommended: 2 Coverage per gallon sq ft

3. Buying allowance

Waste / touchup allowance % Price per gallon optional

How to measure for paint

For a full room, measure the length and width of the room, then measure the wall height.
For an accent wall or partial project, choose exact area and enter the wall square footage.
Subtract large doors and windows, but keep a small safety allowance for touchups, trim lines, and roller waste.
Use the paint coverage number on the can. Many paints cover about 350 to 400 square feet per gallon, but coverage depends on the product, wall texture, and color change.
Add extra if you are painting textured walls, dark colors, raw drywall, or a major color change.

Paint buying tips

Two coats usually gives the best finish, especially when changing colors.
Primer may be needed for raw drywall, stains, glossy surfaces, or drastic color changes.
Keep a labeled leftover container for future touchups.
Confirm final quantities with your painter for large or expensive projects.