Paint Calculator - Calculate Paint Needed for Room

About this tool

Our Paint Calculator takes the guesswork out of home improvement projects by providing accurate estimates of how much paint you'll need for any room. Whether you're refreshing a single bedroom, painting an entire house, or tackling a commercial project, this tool calculates the exact amount of paint required based on your specific dimensions. The calculator accounts for doors, windows, and other non-paintable areas to ensure you don't over-purchase or run short mid-project. It supports different paint types with varying coverage rates: primer (typically 200-300 sq ft per gallon), standard paint (350-400 sq ft per gallon), and high-quality paint (400-450 sq ft per gallon).

Unlike simple square footage calculators that ignore real-world factors, our tool includes multiple coats in the calculation, which is essential since most painting projects require at least two coats for proper coverage and color saturation. The calculator also factors in industry-standard waste percentages (typically 10%) to account for roller absorption, spillage, and uneven surfaces. For complex rooms with vaulted ceilings, sloped walls, or unusual shapes, you can adjust the dimensions accordingly or calculate sections separately and sum the results.

The cost estimation feature helps you budget your painting project by calculating total paint costs based on your local paint prices. This allows you to compare different paint brands and qualities to find the best value. The tool shows you per-gallon and total project costs, helping you decide between premium and economy paints. Many homeowners find that spending slightly more on high-quality paint actually saves money in the long run because it provides better coverage (fewer coats needed) and lasts longer without fading or peeling.

Professional painters and DIY enthusiasts rely on accurate paint calculations to avoid costly mistakes. Under-ordering paint means color matching issues if you need to buy more later (even the same product can have slight batch variations). Over-ordering wastes money and creates storage problems for leftover paint. Our calculator strikes the perfect balance, ensuring you have exactly what you need plus a small safety margin for touch-ups down the road.

Usage examples

Walls: 384 sq ft → 2.5 gallons. Ceiling: 144 sq ft → 0.9 gallons

Walls: 630 sq ft → 4.0 gallons. Ceiling: 300 sq ft → 1.8 gallons

Walls: 224 sq ft → 1.5 gallons. Ceiling: 48 sq ft → 0.3 gallons

Total: 1400 sq ft → 9.0 gallons exterior paint needed

How to use

1. Enter room dimensions: length, width, and ceiling height in feet
2. Input the number of doors and windows to subtract their areas
3. Select number of coats (1-3) you plan to apply
4. Choose paint type (coverage varies: primer 200-300, standard 350-400 sq ft/gal)
5. Enter paint price per gallon for cost estimation
6. View results showing gallons needed, paintable area, and total cost
7. See separate calculations for walls, ceiling, and trim if needed

Benefits

• Accurate calculations based on room dimensions and paint coverage
• Accounts for doors, windows, and non-paintable areas
• Supports multiple coats (1, 2, or 3) for proper coverage
• Different paint types with varying coverage rates
• Separate calculations for walls, ceiling, and trim
• Cost estimation helps budget your project
• Includes 10% waste factor for realistic estimates
• Prevents over-ordering and under-ordering paint
• Mobile-friendly for use at the paint store
• Free tool with no registration required

FAQs