Paint Coverage Calculator
Estimate exactly how many gallons of paint you need for walls, ceilings, and trim. No more guessing at the hardware store.
Room Dimensions
Painting Tips for Accurate Estimates
Measure Carefully
Always measure each wall individually. For irregular rooms, break the space into rectangles. Round up to the nearest foot to avoid underestimating.
Account for Doors & Windows
Subtract 20 sq ft per door and 15 sq ft per window. Our calculator includes a 10% waste factor to cover minor cut-ins and touch-ups.
Primer Changes Everything
If you're painting over bare drywall or a dark color, plan for a separate primer coat. Primer covers about 200–300 sq ft per gallon.
Buy a Little Extra
It's better to have an unopened gallon you can return than to run out mid-project. Most retailers accept returns on unopened paint.
Frequently Asked Questions
How many square feet does one gallon of paint cover?
Most interior latex paints cover approximately 350–400 square feet per gallon on smooth, primed surfaces. Textured walls, fresh drywall, or deep color changes may reduce coverage to 250–300 sq ft per gallon.
Do I need more paint for dark or bold colors?
Yes. Deep reds, navy blues, and bright yellows often require 3 or more coats for full hide, especially when going over a light base. Our calculator lets you adjust the number of coats accordingly.
Should I include the ceiling in my calculation?
Only if you plan to paint the ceiling. Ceiling paint is typically flat white and sold separately. Check the "Ceiling" box in the calculator to include it in your estimate.
What is the standard waste factor?
We add a 10% waste factor to account for spills, touch-ups, and roller absorption. For very detailed trim work, consider adding an extra quart.