Paint Calculator
Calculate exactly how much paint you need for your room or entire house. No more overbuying or extra trips to the store.
Room Dimensions
Subtract Openings
Results
Total Area
—
sq ft
Paint Needed
—
gallons
Est. Cost
—
at $35/gal
How to use the paint calculator.
- Enter your room's length and width in feet.
- Adjust the wall height if it's not the standard 8 feet.
- Select how many coats you plan to apply (2 is recommended for most jobs).
- Enter the number of doors and windows to subtract from the total area.
- Click "Calculate" to see your results instantly.
Frequently asked questions.
How much does a gallon of paint cover?
One gallon of interior paint typically covers about 350 square feet with one coat on smooth, primed surfaces. Rough or textured surfaces may reduce coverage by 15-20%.
Do I need a primer?
Primer is recommended when painting over dark colors, new drywall, or stained surfaces. Many modern paints include primer (paint + primer in one), which can save you a coat.
How many coats of paint do I need?
Two coats is standard for most interior painting jobs. You may need three coats when going from a dark color to a light one, or when using a paint without primer.
Should I buy extra paint?
Yes — buy about 10% more than calculated for touch-ups and future repairs. Store leftover paint in a cool, dry place with the lid sealed tightly.