Paint Coverage Calculator - How Much Paint Do I Need?
Calculate exactly how many gallons of paint you need for your project. Includes wall area calculation, coverage rates by paint type, and cost estimates.
Room Details
Room Dimensions
Openings to Subtract
~21 sq ft each
~15 sq ft each
Paint Needed
Gallons Needed
2
(1.77 exact)
Estimated Cost
$90
$45/gallon
Paint Coverage Rates by Type (2025 Guide)
| Paint Type | Coverage (sq ft/gal) | Best For | Avg Price/Gallon |
|---|---|---|---|
| Primer | 200-300 | New drywall, stain blocking | $25-45 |
| Latex (Water-Based) | 350-400 | Interior walls, low odor | $30-60 |
| Oil-Based | 350-450 | Trim, cabinets, high-traffic | $40-70 |
| Ceiling Paint | 350-400 | Ceilings, flat finish | $25-50 |
| Exterior Paint | 250-350 | Outdoor surfaces, weather-resistant | $35-75 |
Paint Needed by Room Size (Quick Reference)
Common Room Sizes
*Based on 9ft ceilings, 2 coats
Exterior Projects
*Varies by siding type
Professional Painting Tips
Before You Start
- 1.Buy 10% Extra: Always round up and buy extra for touch-ups
- 2.Same Batch: Buy all paint at once to ensure color consistency
- 3.Test First: Buy a sample quart and test on the wall
- 4.Primer Matters: Use primer for new drywall or dark-to-light changes
Application Tips
- 1.Two Coats: Always apply 2 coats for best coverage and durability
- 2.Dry Time: Wait 2-4 hours between coats (check label)
- 3.Temperature: Paint between 50-85°F for best results
- 4.Humidity: Avoid painting when humidity is above 85%
Frequently Asked Questions
How much paint do I need for a 12x12 room?
For a standard 12×12 room with 9-foot ceilings, you'll need approximately 2 gallons of paint for two coats. This accounts for about 432 square feet of wall space minus doors and windows. If you're making a dramatic color change, consider 3 gallons to ensure full coverage.
Should I use one coat or two coats of paint?
Always use two coats for the best results. One coat rarely provides adequate coverage, especially when changing colors. Two coats ensure even color, better durability, and longer-lasting results. The only exception is touch-up work on the same color.
How do I calculate paint for textured walls?
Textured walls require 15-25% more paint than smooth walls. For light texture (orange peel), add 15% to your calculation. For heavy texture (knockdown or popcorn), add 25%. Our calculator automatically adjusts for surface type when you select "Textured" or "Rough."
What's the difference between latex and oil-based paint?
Latex (water-based) paint is easier to clean up, dries faster, has less odor, and is better for most interior walls. Oil-based paint is more durable, provides a smoother finish, and is ideal for trim, cabinets, and high-traffic areas. However, oil-based paint requires mineral spirits for cleanup and has stronger fumes.