Paint Calculator

Calculate the amount of paint needed for your room based on dimensions and coats

Project Details
Enter your measurements and requirements
$
Results
Calculated estimates for your project

Wall Area

0.0 sq ft

Paintable Area

0.0 sq ft

Total Area (2 coats)0.0 sq ft
Coverage per Gallon375 sq ft
Gallons Needed0
Total Cost$0.00
Materials List
Recommended materials and quantities
Paint (0 gallon)$0.00
Primer (if needed)$0.00
Painter's Tape (2 rolls)$12.00
Paint Roller & Tray$15.00
Brushes (2-3 count)$20.00
Estimated Total$47.00

Additional Information

About This Paint Calculator

Our paint calculator helps you determine exactly how much paint you need for your room painting project. Whether you're painting a bedroom, living room, bathroom, or entire house, this tool calculates the gallons of paint required based on your room dimensions, number of coats, and accounts for doors and windows that won't be painted.

Accurate paint estimation saves money by preventing over-purchasing and eliminates frustrating trips back to the store for more paint mid-project. The calculator uses industry-standard coverage rates of approximately 375 square feet per gallon, which accounts for typical wall textures and paint absorption. For heavily textured walls or porous surfaces, you may need 10-15% more paint.

This tool is perfect for DIY homeowners tackling their first paint project, experienced painters planning material purchases, contractors preparing estimates, and anyone wondering "how much paint do I need for a 12x12 room?" The calculator also provides cost estimates to help you budget for your painting project.

How to Use This Calculator

Follow these simple steps to calculate your paint needs:

  1. Measure your room's length and width in feet using a tape measure
  2. Measure the ceiling height (standard is 8 feet, but many homes have 9 or 10-foot ceilings)
  3. Count the number of doors and windows in the room
  4. Select how many coats you plan to apply (2 coats is recommended for best coverage)
  5. Enter the cost per gallon of your chosen paint to get a total project cost estimate
Frequently Asked Questions

How much paint do I need for a 12x12 room?

A standard 12x12 room with 8-foot ceilings has about 384 square feet of wall space. After subtracting for one door and one window, you'll have roughly 348 square feet of paintable area. For two coats, you'll need approximately 2 gallons of paint. If you're making a dramatic color change or painting over dark colors, consider 3 gallons.

Should I use one coat or two coats of paint?

Two coats of paint is recommended for most projects to ensure even coverage, rich color, and durability. One coat may be sufficient when using paint-and-primer-in-one products for minor touch-ups or when painting the same color. Always apply two coats when changing colors dramatically, covering dark colors with light ones, or painting new drywall.

How many square feet does a gallon of paint cover?

A gallon of paint typically covers 350-400 square feet on smooth surfaces. Our calculator uses 375 square feet as an average. Coverage varies based on surface texture, paint quality, and application method. Rough or textured walls may reduce coverage to 300 square feet per gallon, while smooth drywall may allow up to 400 square feet per gallon.

Do I need primer before painting?

Primer is recommended when painting new drywall, covering stains or water damage, making dramatic color changes (especially from dark to light), painting over glossy surfaces, or when the existing paint is in poor condition. Many modern paints include primer, but for best results on challenging surfaces, a dedicated primer coat helps paint adhere better and provides more uniform coverage.

How do I calculate paint for walls with vaulted ceilings?

For vaulted or cathedral ceilings, measure the height at the highest point and calculate each wall section separately. You can use this calculator multiple times for different wall sections and add the results together. Alternatively, use the average height between the lowest and highest points as your ceiling height input for a quick estimate.

How much extra paint should I buy for touch-ups?

It's wise to purchase an extra quart or half-gallon for future touch-ups. Paint colors can vary slightly between batches, so having leftover paint from your original project ensures perfect color matching. Store leftover paint in a cool, dry place with an airtight seal. Label the can with the room name and date for easy identification.

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