Paint Calculator

Calculate how much paint you need for walls, rooms, and ceilings. Enter dimensions to find gallons needed.

Room Length (ft)

Room Width (ft)

Wall Height (ft)

Number of Doors (21 sq ft each)

Number of Windows (15 sq ft each)

Number of Coats

How to Use the Paint Calculator

Enter the length, width, and height of your room in feet, along with the number of doors and windows. Select the number of coats you plan to apply (one, two, or three). The calculator computes the total wall area, subtracts openings, and tells you how many gallons of paint you need to purchase.

Tips for Accurate Paint Estimation

This calculator uses the standard industry coverage rate of 350 square feet per gallon. For best results, measure your room dimensions carefully and count all doors and windows. The result is rounded up to the nearest whole gallon since paint is sold in full gallons. Always consider buying a little extra for touch-ups and future repairs.

Frequently Asked Questions

How much area does a gallon of paint cover?

A gallon of paint typically covers about 350 square feet of smooth, non-porous surface with one coat. Rough or textured surfaces, dark colors painted over light colors, or very porous surfaces may reduce coverage to 200-300 square feet per gallon.

How many coats of paint do I need?

Two coats are recommended for most projects to ensure even coverage and color consistency. You may need only one coat when using paint-and-primer-in-one over a similar color, or three coats when covering a very dark color with a light one.

Should I subtract doors and windows from the paint calculation?

Yes, subtracting the area of doors (approximately 21 sq ft each) and windows (approximately 15 sq ft each) gives a more accurate estimate and helps you avoid buying too much paint. This calculator handles the subtraction automatically.

How do I estimate paint for a room with vaulted ceilings?

For rooms with vaulted or cathedral ceilings, measure the height at the tallest point and use that as the wall height. This will slightly overestimate the paint needed, which provides a comfortable margin for the project.