Work out how much paint a room needs before you head to the store. Enter the total length of the walls you plan to cover, the ceiling height, and how many standard doors and windows to subtract, then choose a coverage rate and number of coats. This calculator returns the paintable square footage and the gallons required, rounded up so you never run short mid job. Most interior latex paints cover roughly 350 to 400 square feet per gallon on primed drywall, though porous or dark surfaces drink more. Doors are treated as about 20 square feet each and windows as 15, which are typical values you can adjust by editing the counts. Everything is calculated instantly in your browser, so you can try several room sizes and coat counts in seconds without any signup.
It finds the total wall area from length and height, subtracts door and window area, then divides by the coverage per gallon and multiplies by the number of coats.
A gallon typically covers around 350 to 400 square feet on smooth walls, and the calculator uses a standard coverage figure to size your order.
Yes. Entering doors and windows removes their area so you do not overbuy paint for surfaces you will not paint.
Work out how much paint a room needs before you head to the store. Enter the total length of the walls you plan to cover, the ceiling height, and how many standard doors and windows to subtract, then choose a coverage rate and number of coats.
Yes. Paint Calculator is completely free, with no sign-up and no usage limits.
Yes. Paint Calculator runs in any modern web browser. There is nothing to download or install.
Yes. Paint Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.