Paint Calculator
Enter your total wall length, ceiling height, number of coats, and openings to deduct. Get the paintable area and gallons needed.
Results
- Paint needed
- 3 gal
- Paintable area
- 438 sq ft
- Coverage with coats
- 876 sq ft
Estimates only. Round up and buy a little extra to account for waste, spills, and breakage.
Enter your total wall length, ceiling height, number of coats, and openings to deduct. Get the paintable area and gallons needed.
Also used as a wall paint estimator and interior paint coverage calculator.
How to use the paint calculator
- Enter the total wall length in ft.
- Enter the wall height in ft.
- Enter the number of coats.
- Enter the doors & windows.
- Optionally add a price to estimate the total project cost.
- Read your quantities instantly — no sign-up, and you can print the estimate to take to the supplier.
Worked example
Inputs
- Total wall length
- 60 ft
- Wall height
- 8 ft
- Number of coats
- 2
- Doors & windows
- 2
Results
- Paint needed
- 3 gal
- Paintable area
- 438 sq ft
- Coverage with coats
- 876 sq ft
Using the example values above, the paint calculator returns 3 gal (paint needed). Change any field to match your own project and the numbers update instantly.
Formula
Gallons = (paintable area × coats) ÷ 350. Each opening deducts ~21 sq ft.
Frequently asked questions
- How much area does a gallon of paint cover?
- About 350 sq ft per coat on smooth, primed surfaces.
- Do I need two coats?
- Most color changes need two coats; same-color refreshes may need only one.
- How many gallons of paint do I need?
- Divide paintable area by 350 sq ft per coat, then multiply by the number of coats. A 12×12 room usually takes 1–2 gallons for two coats.
Related calculators
Drywall Calculator
Estimate drywall sheets for walls and ceilings.
Square Footage Calculator
Calculate the area of a room or surface in square feet, yards, and meters.
Flooring Calculator
Estimate boxes of flooring with a waste factor for any room.
Siding Calculator
Estimate siding squares for your home's exterior walls.