Quantity & Materials Tool
Paint Calculator
Estimate how many gallons of paint you need for a wall or surface.
Surface Details
# About This Calculator
Painting is one of the most cost-effective ways to transform a room, but buying too much or too little paint is a hassle.
This calculator provides a precise estimate of the gallons required based on your wall dimensions and the number of coats. It's designed to save you money and keep your garage from cluttering up with half-empty paint cans.
Paint Coverage Rules
- Standard Coverage: Most residential paint covers between 350 and 400 square feet per gallon.
- Textured Walls: Rough surfaces (stucco, popcorn, brick) absorb more paint. Reduce your coverage estimate to ~300 sq ft/gal.
- Color Change: Going from dark to light (e.g., navy blue to white) often requires a premium primer or 3 coats of paint.
Do I Need 1 or 2 Coats?
Professionals almost always recommend two coats. The first coat seals the surface and provides a base; the second coat gives you the true, rich color and even finish that you see on paint chips.
How To Use
- Measure the **Width** and **Height** of the wall or surface (in feet).
- Enter the **Number of Coats** (2 is standard).
- Adjust **Coverage** if using specialty paint (default is 350 sq ft/gal).
- Click Calculate to see the gallons required.
Frequently Asked Questions
How much does a gallon of paint cover?+
Typically, one gallon of paint covers about 350 to 400 square feet, depending on the brand and texture of the wall.
How many gallons of paint do I need for a 12x12 room?+
For a standard 12x12 room with 8ft ceilings, the wall area is (12+12+12+12) * 8 = 384 sq ft. One gallon covers ~350 sq ft, so you would likely need just over 1 gallon for one coat, or 2 gallons for two coats.
Do I need 2 coats of paint?+
Yes, 2 coats are recommended for most projects to ensure true color, coverage, and durability, especially when covering darker colors.
How do I calculate ceiling paint?+
Multiply the room's length by its width. For a 10x12 room, the ceiling is 120 sq ft. One quart might suffice, but usually 1 gallon is safest for 2 coats.
Should I subtract windows and doors?+
For a quick estimate, pros often ignore windows and doors to account for waste and touch-ups. If you have a wall of windows, calculate the total area and subtract roughly 15-20 sq ft per door/window.
Is Paint Calculator free to use?+
Yes, Paint Calculator on Matheric is completely free to use. We believe in accessible education and utility for everyone.