Paint Calculator
Calculate paint requirements and costs for your painting project
Room Dimensions
Most projects need 2 coats
Typical: 350 sq ft/gal
To calculate total cost
Results
Enter room dimensions to calculate
Quick Room Presets
How to Use the Paint Calculator
Our paint calculator helps you determine exactly how much paint you need for your interior painting project. Simply enter the dimensions of each room, and the calculator will account for doors, windows, and multiple coats to give you accurate estimates.
The calculator automatically deducts standard door (20 sq ft) and window (15 sq ft) areas from your total wall surface. You can customize paint coverage rates based on your specific paint brand and surface texture. Most paints cover approximately 350 square feet per gallon on smooth surfaces.
Paint Calculation Tips
Measure Accurately
Use a tape measure to get precise room dimensions. Measure length, width, and ceiling height in feet or meters.
Account for Multiple Coats
Most painting projects require 2 coats for even coverage. Dark colors or dramatic color changes may need 3 coats.
Buy Extra Paint
Purchase 10-15% more paint than calculated for touch-ups, waste, and color matching in the future.
Consider Surface Texture
Rough or textured walls absorb more paint. Reduce coverage to 300 sq ft/gallon for textured surfaces.
Paint Coverage Guide
Standard Coverage
Most interior paints cover approximately 350-400 square feet per gallon on smooth, primed surfaces. This assumes one coat application.
Textured Surfaces
Rough or heavily textured walls require more paint, typically covering 250-350 square feet per gallon due to increased surface area and absorption.
Primer Considerations
Always prime new drywall, patched areas, or when making dramatic color changes. Primer typically covers 300-400 square feet per gallon.
Frequently Asked Questions
How accurate is this paint calculator?
Our calculator provides accurate estimates based on standard paint coverage rates and average door/window sizes. For best results, always purchase 10-15% extra paint to account for waste, touch-ups, and coverage variations.
Should I paint the ceiling?
This calculator focuses on wall painting. If you're painting the ceiling, add the ceiling area (length × width) to your total and increase your paint estimate accordingly. Ceilings typically require flat or matte finish paint.
What if I have vaulted or cathedral ceilings?
For vaulted ceilings, use the average height (lowest point + highest point ÷ 2) or add a second room entry with the additional wall area from the vault. Vaulted spaces require significantly more paint.
How many coats of paint do I need?
Most projects require 2 coats for even coverage. You may need 3+ coats when painting over dark colors, covering stains, or using light colors over dark walls. Premium paints may offer one-coat coverage in some situations.
Is this calculator suitable for exterior painting?
This calculator is optimized for interior painting. Exterior projects have different coverage rates due to surface materials (wood, stucco, brick) and typically require specialized exterior paint with different coverage characteristics.