Paint Calculator
Estimate paint gallons needed for walls, ceilings, and trim
Length of the room
Width of the room
Height of walls
Standard door: 20 sq ft
Standard window: 15 sq ft
Most projects need 2 coats
Wall Area
—
sq ft
Paintable Area
—
sq ft
Paint Needed
—
gallons
Estimated Cost
—
USD
Disclaimer: Results are estimates based on standard formulas. Not a substitute for professional advice from a licensed contractor, engineer, or architect. Verify all calculations before making purchasing or construction decisions.
How to Use This Calculator
Buying the right amount of paint saves you time and money. Our paint calculator accounts for room dimensions, doors, windows, and number of coats.
- Measure room length, width, and ceiling height
- Count the number of doors and windows
- Decide how many coats you will apply
- Enter your measurements in the calculator
- Buy 10% extra for touch-ups
AI Insights
Smart analysis for your project
Smart Estimates
Our AI cross-references material costs, regional pricing, and project complexity for more accurate estimates.
Waste Optimization
AI-calculated waste factors based on project type, not flat percentages. Saves 5-15% on material costs.
Best Practices
Recommendations derived from building codes, contractor data, and thousands of completed projects.
Calculation Formula
Wall area = 2 x (L + W) x H
Paintable = Wall area - (Doors x 20) - (Windows x 15)
Gallons = (Paintable x Coats) / 350
Frequently Asked Questions
How much does a gallon of paint cover?
One gallon of interior paint typically covers 350-400 square feet with one coat.
How many coats of paint do I need?
Most projects require 2 coats. You may need 3 when painting over dark colors or on bare drywall without primer.