Paint Calculator
Calculate how much paint you need for any room. Enter wall dimensions, doors, windows, and coats to get gallons and cans needed.
Total Wall Area
396 sq ft
Net Paintable Area
346 sq ft
Gallons Needed
1.98 gal
Liters Needed
7.5 L
Recommended Purchase
Tip: add 10–15% extra for touch-ups and waste.
What Is the Paint Calculator?
The Paint Calculator estimates how much paint you need for a room or project. Enter the dimensions of each wall, subtract doors and windows, choose the number of coats, and get the total gallons and liters needed — plus how many cans to buy.
How to Use
- Add each wall with its width and height
- Enter the number of doors and windows to subtract their area
- Choose the number of coats (typically 2 for full coverage)
- Adjust the coverage rate if your paint label specifies a different value
- Results show gallons, liters, and recommended can sizes
Features
- Add multiple walls for a full room calculation
- Automatic door (20 sq ft) and window (15 sq ft) deductions
- Supports feet and meters
- Configurable coverage rate (default 350 sq ft/gallon)
- Results in gallons, liters, quart cans, and gallon cans
FAQ
How much does a gallon of paint cover?
Most interior paints cover 350–400 sq ft per gallon per coat on smooth surfaces. Rough or porous surfaces may require more. Always check your paint can's label for the exact coverage rate.
How many coats do I need?
Two coats are standard for most projects. Going from a dark to a light color may require 3 coats. Primer coats are separate and not included in this calculation.
Should I buy extra paint?
Yes — add 10–15% extra for touch-ups, waste, and uneven surfaces. The calculator gives the theoretical minimum; always round up to the next can size.