What affects paint coverage?

Surface texture is the biggest factor—smooth walls cover more than textured. Color changes matter too: covering dark with light or vice versa needs more paint. New drywall absorbs more paint than previously painted surfaces. Primer helps with difficult surfaces.

Should I buy extra paint?

Our calculator includes a 10% buffer in the recommended amount. This accounts for waste, spills, and touch-ups. Keep leftover paint for future touch-ups—store in a cool, dry place with the lid tightly sealed.

How do I estimate for odd-shaped rooms?

Break the room into rectangular sections and add them together. For vaulted ceilings, calculate as if flat then add 20%. For accent walls, measure just that wall's dimensions and calculate separately.

What's the difference in paint quality?

Budget paint (~$25-35/gal) works for rentals or low-traffic areas. Mid-range (~$40-55/gal) offers good coverage and durability for most homes. Premium (~$60-80/gal) provides excellent coverage, durability, and often includes primers.

Construction

Paint Calculator

Determine the exact amount of paint needed for walls, ceilings, and rooms based on dimensions and openings

Unit System

Room Dimensions

Length

Width

Ceiling Height

Openings to Exclude

Number of Doors

Number of Windows

Paint Options

Number of Coats

Paint Coverage

sq ft/gal

Include ceiling in calculations

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Calculate Exactly How Much Paint You Need

Planning a painting project? Our paint calculator helps you determine the precise amount of paint needed for any room or surface. Avoid buying too much or running short mid-project by calculating based on your room dimensions, number of doors and windows, and desired number of coats. Get accurate estimates in gallons or liters with cost projections.

How Paint Coverage Works

Paint coverage varies by type and surface, but most interior latex paints cover approximately 350-400 square feet per gallon on smooth surfaces. Textured walls, porous surfaces, or dramatic color changes may require more paint. We calculate the paintable area by measuring walls (and optionally ceilings), then subtracting doors and windows to give you an accurate estimate.

Paint Calculation Formula

Paint Needed = (Wall Area + Ceiling Area - Doors/Windows) × Coats ÷ Coverage Rate

How to Calculate Paint Needed

Common Use Cases

DIY Home Projects

Plan your painting project with accurate paint quantities before heading to the store.

Contractor Estimates

Create accurate material quotes for painting jobs and avoid under or over-ordering.

Budget Planning

Estimate total paint costs across different quality levels before starting your project.

Multi-Room Projects

Calculate paint needs for multiple rooms to buy in bulk and save money.

Frequently Asked Questions

Most projects require 2 coats for even coverage and durability. Use 1 coat only for touch-ups or repainting the same color. Consider 3 coats when covering dark colors with light, using deep/bold colors, or painting over bare drywall.