Paint Calculator
Estimate how much paint you need for walls, ceilings and other surfaces. Calculate gallons, liters, coverage and optional paint cost.
Doors and windows
Estimates are based on the coverage and measurements you enter. Actual paint needs can vary by surface texture, application method, paint type, and manufacturer coverage.
Need Expert Advice?
Have questions about your project? Tell us a little about it and a local professional may contact you.
How much paint do I need?
Use this paint calculator to estimate how much paint you may need for walls, ceilings and other surfaces. Enter room dimensions or a surface area, choose the number of coats and use the paint coverage shown on your product label to get an estimate in gallons and liters.
For a room, the calculator can account for doors and windows. You can also add an extra or waste allowance and an optional price per gallon to estimate your paint cost.
How the paint calculator works
The calculator first estimates the paintable surface area. For room dimensions, wall area is based on the room length, width and wall height. Doors and windows can then be deducted. If you include the ceiling, the ceiling area is added to the wall area.
After the surface area is calculated, the tool applies your number of coats, paint coverage and extra allowance. The result shows the estimated gallons and liters of paint.
Paint calculator for square feet
If you work in feet, select Feet / Square Feet. You can enter room dimensions or enter a known surface area in square feet. This makes the tool useful as a paint calculator square feet users can use for walls, ceilings and other paintable areas.
Wall paint calculator
For a wall paint calculator estimate, enter the room length, width and wall height. The calculator can subtract doors and windows so the result is closer to the actual paintable wall area. If you already know the total wall area, use the surface-area option instead.
Ceiling paint calculator
For a ceiling paint calculator estimate, choose Ceiling only and enter the room length and width. The calculator uses the ceiling area, number of coats, coverage and extra allowance to estimate the amount of paint needed.
Paint coverage calculator
Paint coverage varies by product and surface. This paint coverage calculator lets you enter your own coverage in square feet per gallon instead of relying on a fixed coverage rate. For the most useful estimate, use the coverage information provided by the paint manufacturer.
Interior and exterior paint calculator
This calculator can be used for many interior and exterior projects when you know the paintable surface area. For an interior paint calculator estimate, you can calculate room walls and ceilings. For an exterior paint calculator estimate, use the known surface-area option when you already have the exterior area.
Paint cost calculator
If you know the price per gallon, enter it in the optional price field. The calculator will use the estimated gallons to show an estimated paint cost. This is a material estimate only and does not include labor, primer, tools or other project expenses.
Paint calculator in meters
The calculator also supports meters and square meters. Select Meters / Square Meters when you want to enter metric room dimensions or a known surface area in square meters. Results are shown in both square meters and square feet, with paint quantity shown in gallons and liters.
Tips for getting a better paint estimate
- Measure each paintable area carefully.
- Use the manufacturer coverage rate when it is available.
- Include the number of coats you actually plan to apply.
- Use an extra allowance when the surface is textured, porous or difficult to cover.
- For large or unusual projects, compare the calculator estimate with the paint manufacturer guidance.
Paint calculator FAQ
How do I calculate how much paint I need?
Estimate the paintable area, multiply it by the number of coats, then divide by the paint coverage per gallon. Adding an extra allowance can help account for waste and surface differences.
How many gallons of paint do I need for a room?
It depends on the room dimensions, doors and windows, number of coats and the paint coverage rate. Enter those details above for an estimate.
How much paint do I need for 1,000 square feet?
There is no single answer because coverage and coats vary. For example, at 350 square feet per gallon and two coats, 1,000 square feet would require about 6.29 gallons after a 10% extra allowance.
How much paint do I need for a ceiling?
Choose Ceiling only, enter the ceiling length and width, then select the number of coats and coverage rate. The calculator will estimate the required paint.
Can I use this as a paint cost calculator?
Yes. Enter your price per gallon and the calculator will add an estimated paint cost to the results.
Can I use this calculator for exterior paint?
Yes. If you know the exterior paintable area, choose the known surface-area option and enter the area. Exterior surfaces can vary significantly, so use the manufacturer coverage information when available.
Related calculators
Planning another home improvement project? Try our Gravel Calculator or Concrete Calculator, or browse the calculator directory for more tools.