Calculate exactly how many gallons of paint you need before you head to the store. One gallon of interior paint typically covers 350 to 400 square feet per coat on smooth drywall — but trim, doors, and windows all affect the total. Enter your room dimensions, ceiling height, number of doors and windows, and number of coats, and our paint calculator will give you an accurate gallon estimate. This calculator covers wall paint — use the ceiling paint calculator separately for ceiling coverage.
Enter Your Measurements
Results
Paint Needed
1.8
gallons
Paintable Area
312
sq ft
Total Wall Area
384
sq ft
Cost Estimate
per gallon
Estimated Cost
$71.31
Formula
How to Use This Calculator
How to Use
- 1
Enter the room length and width in feet — measure wall to wall for each dimension.
- 2
Enter the ceiling height, typically 8 feet in most homes (9 or 10 feet in newer construction).
- 3
Enter the number of standard doors (each treated as 21 sq ft) and windows (each treated as 15 sq ft) to subtract from the paintable area.
- 4
Set the number of coats — 2 is standard for most projects, but going from a dark color to a light one may require 3 coats.
Frequently Asked Questions
Frequently Asked Questions
How much paint do I need for a 12x12 room?
How many gallons of paint do I need for a 2,000 sq ft house exterior?
Do I need primer before painting?
How much does it cost to paint a room?
How much extra paint should I buy for touch-ups?
Can I use leftover paint for touch-ups years later?
In-Depth Guides
How Much Paint Do You Need? Room-by-Room Guide
Calculate exactly how many gallons of paint you need for any room. Covers wall measurement, door/window deductions, coats, primer, and paint sheen selection.
Exterior House Painting Cost Guide: Calculate Paint & Labor
Calculate how much paint and labor costs to paint a house exterior. Coverage rates, paint types, DIY vs professional, and cost per square foot.
How to Calculate Square Footage: Room, House & Irregular Shapes
Learn to calculate square footage for rooms, houses, and irregular shapes. Includes examples for L-shaped rooms, triangles, circles, and total home area.
Kitchen Remodel Cost Guide: Budget to High-End (2026)
Complete kitchen remodel cost breakdown for 2026: budget ($15k-$30k), mid-range ($30k-$60k), and high-end ($60k+). See what's included at each level.
House Painting Costs in Alabama: 2026 Price Guide
How much does it cost to paint a house in Alabama? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Alaska: 2026 Price Guide
How much does it cost to paint a house in Alaska? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Arizona: 2026 Price Guide
How much does it cost to paint a house in Arizona? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Arkansas: 2026 Price Guide
How much does it cost to paint a house in Arkansas? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in California: 2026 Price Guide
How much does it cost to paint a house in California? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Colorado: 2026 Price Guide
How much does it cost to paint a house in Colorado? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Connecticut: 2026 Price Guide
How much does it cost to paint a house in Connecticut? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Delaware: 2026 Price Guide
How much does it cost to paint a house in Delaware? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Florida: 2026 Price Guide
How much does it cost to paint a house in Florida? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Georgia: 2026 Price Guide
How much does it cost to paint a house in Georgia? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Hawaii: 2026 Price Guide
How much does it cost to paint a house in Hawaii? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Idaho: 2026 Price Guide
How much does it cost to paint a house in Idaho? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Illinois: 2026 Price Guide
How much does it cost to paint a house in Illinois? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Indiana: 2026 Price Guide
How much does it cost to paint a house in Indiana? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Iowa: 2026 Price Guide
How much does it cost to paint a house in Iowa? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Kansas: 2026 Price Guide
How much does it cost to paint a house in Kansas? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Kentucky: 2026 Price Guide
How much does it cost to paint a house in Kentucky? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Louisiana: 2026 Price Guide
How much does it cost to paint a house in Louisiana? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Maine: 2026 Price Guide
How much does it cost to paint a house in Maine? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Maryland: 2026 Price Guide
How much does it cost to paint a house in Maryland? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Massachusetts: 2026 Price Guide
How much does it cost to paint a house in Massachusetts? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Michigan: 2026 Price Guide
How much does it cost to paint a house in Michigan? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Minnesota: 2026 Price Guide
How much does it cost to paint a house in Minnesota? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Mississippi: 2026 Price Guide
How much does it cost to paint a house in Mississippi? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Missouri: 2026 Price Guide
How much does it cost to paint a house in Missouri? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Montana: 2026 Price Guide
How much does it cost to paint a house in Montana? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Nebraska: 2026 Price Guide
How much does it cost to paint a house in Nebraska? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Nevada: 2026 Price Guide
How much does it cost to paint a house in Nevada? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in New Hampshire: 2026 Price Guide
How much does it cost to paint a house in New Hampshire? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in New Jersey: 2026 Price Guide
How much does it cost to paint a house in New Jersey? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in New Mexico: 2026 Price Guide
How much does it cost to paint a house in New Mexico? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in New York: 2026 Price Guide
How much does it cost to paint a house in New York? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in North Carolina: 2026 Price Guide
How much does it cost to paint a house in North Carolina? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in North Dakota: 2026 Price Guide
How much does it cost to paint a house in North Dakota? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Ohio: 2026 Price Guide
How much does it cost to paint a house in Ohio? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Oklahoma: 2026 Price Guide
How much does it cost to paint a house in Oklahoma? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Oregon: 2026 Price Guide
How much does it cost to paint a house in Oregon? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Pennsylvania: 2026 Price Guide
How much does it cost to paint a house in Pennsylvania? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Rhode Island: 2026 Price Guide
How much does it cost to paint a house in Rhode Island? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in South Carolina: 2026 Price Guide
How much does it cost to paint a house in South Carolina? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in South Dakota: 2026 Price Guide
How much does it cost to paint a house in South Dakota? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Tennessee: 2026 Price Guide
How much does it cost to paint a house in Tennessee? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Texas: 2026 Price Guide
How much does it cost to paint a house in Texas? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Utah: 2026 Price Guide
How much does it cost to paint a house in Utah? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Vermont: 2026 Price Guide
How much does it cost to paint a house in Vermont? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Virginia: 2026 Price Guide
How much does it cost to paint a house in Virginia? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Washington: 2026 Price Guide
How much does it cost to paint a house in Washington? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in West Virginia: 2026 Price Guide
How much does it cost to paint a house in West Virginia? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Wisconsin: 2026 Price Guide
How much does it cost to paint a house in Wisconsin? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
House Painting Costs in Wyoming: 2026 Price Guide
How much does it cost to paint a house in Wyoming? 2026 price ranges for interior and exterior painting, paint types, and tips for finding local painters.
Related Calculators
Related Calculators
About This Calculator
This calculator uses the formula: Gallons = ((2 × (L + W) × H) - (Doors × 21) - (Windows × 15)) × Coats ÷ 350. All calculations follow industry-standard methods. Results are estimates — always verify with a licensed professional for structural or code-compliant work.
Built and maintained by the CalcSmart team. Last updated March 2026.
▶Embed this calculator on your website
Copy and paste this code into your page:
<iframe src="https://calcsmart.io/embed/paint-calculator" width="100%" height="520" frameborder="0" style="border-radius:8px;border:1px solid #e5e7eb" title="Paint Calculator"></iframe>Free to embed. Attribution link included automatically.