Paint Calculator
Free paint calculator. Enter room size to get the gallons, quarts and litres of paint you need for your walls and ceiling, accounting for doors, windows and coats.
About This Free Online Paint Calculator
Our free paint calculator tells you exactly how much paint to buy for a room. Enter the room’s length, width and wall height, choose whether to include the ceiling, set the number of coats, and subtract doors and windows — the tool instantly returns the total paintable square footage and the gallons, quarts and litres you need (based on 350 sq ft of coverage per gallon). Whether you are painting a bedroom, hallway or whole interior, this avoids overbuying or running out mid-wall. Everything runs in your browser — perfect for homeowners, renters and professional painters.
Features of Our Paint Calculator
- Total paintable area from room length, width and wall height
- Optional ceiling included or excluded
- Subtracts doors and windows automatically
- Adjustable number of coats (1–3)
- Results in gallons, quarts and litres
- 100% client-side and private — instant results, no signup
How to Use the Paint Calculator
Using this tool is simple and requires no signup or registration. Follow these steps:
- Enter the room length, width and wall height in feet.
- Choose whether to paint the ceiling and how many coats you plan.
- Enter the number of doors and windows to subtract.
- Read off the gallons, quarts and litres of paint to buy.
Frequently Asked Questions About Paint Calculator
How much does a gallon of paint cover?
One gallon of quality interior paint covers about 350 square feet with one coat. This calculator uses 350 sq ft per gallon, so it already accounts for typical coverage; porous or heavily patched walls may need slightly more.
How do I calculate paint for a room?
Add the wall area (wall length × height for each wall, or 2 × (length + width) × height for a rectangular room), subtract doors and windows, add the ceiling if needed, then multiply by the number of coats and divide by 350. This tool does it all for you.
Do I need to count doors and windows?
It is a good idea. A standard door is about 21 sq ft and a window about 15 sq ft. Subtracting them avoids buying paint you will not use. You can leave both at zero for a conservative estimate.
How many coats of paint should I apply?
Two coats give the most even, durable finish and true colour, especially over a different colour or fresh primer. One coat can work for a touch-up or same-colour repaint. Use the coats selector to match your project.
Is this paint calculator free?
Yes, completely free with no signup. All maths runs in your browser — your room measurements never leave your device.
Why Choose Text Toolbox?
Text Toolbox provides free, private, and instant online text tools. Unlike other text utility websites that require signup accounts or send your data to servers, all our tools process your text entirely in your browser. This means your content never leaves your device — we cannot see it, store it, or share it. Our tools are fast, lightweight, and work on any device with a modern web browser.