Paint Calculator
The EveryFix Paint Calculator estimates how much paint you need based on your room dimensions, number of doors and windows, and how many coats you plan to apply. Get a quick, reliable gallon estimate before you head to the store.
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How This Tool Works
Enter the length and width of the room, the wall height, and how many doors and windows it has. Choose how many coats you plan to apply, then get an instant gallon estimate rounded up to the nearest quarter gallon.
Formula & Method
We calculate wall area from the room perimeter and height, subtract standard allowances for doors (20 sq ft) and windows (15 sq ft), multiply by the number of coats, then divide by your paint's coverage rate (default 350 sq ft per gallon).
Example Calculation
A 12×10 ft room with 8 ft ceilings, one door, and two windows needs roughly 2 coats. Wall area is about 322 sq ft after deductions; at 350 sq ft per gallon per coat, that's about 1.8 gallons — so plan on buying 2 gallons.
Frequently Asked Questions
How much paint do I need for a 12×12 room?+
For a standard 12×12 room with 8 ft ceilings, one door, and two windows, you'll typically need about 2 gallons for two coats. Use the calculator above with your exact dimensions for a precise number.
Does this account for ceilings?+
No — this calculator estimates wall paint only. If you're painting the ceiling too, calculate its area (length × width) separately and divide by your coverage rate.
Why round up to the nearest quarter gallon?+
Paint stores typically sell in quart and gallon increments, and running short mid-coat can cause visible touch-up lines, so it's safer to round up.
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