Planning to paint your home but unsure how much paint to buy? Estimating paint accurately is essential to avoid waste, reduce costs, and ensure a smooth painting experience.
Use our free Paint Calculator to determine exactly how much paint you need for walls, ceilings, and trim. No more last-minute store runs or leftover paint cans—just a precise, hassle-free way to plan your painting project.
Paint Calculator: Get Your Estimate Instantly
Enter your room dimensions, number of coats, and door/window details to calculate how much paint you need.
Use the Paint Calculator Below
Paint Calculator
Paint Estimation
Why Use a Paint Calculator?
Many homeowners guess how much paint they need, leading to unnecessary expenses or incomplete coverage. Here are the most common mistakes:
- Overbuying paint, leading to wasted money and storage issues.
- Underbuying paint, causing inconsistent colors due to mismatched batches.
- Ignoring doors and windows, which reduces the actual paintable area.
- Forgetting about multiple coats, which changes the total paint requirement.
Using a paint calculator ensures you get the exact amount you need, making your project efficient and cost-effective.
If you’re selecting paint colors for your space, it helps to understand how color theory works. This can help you choose the right tones that complement your home design.
How to Use Our Paint Calculator (Step-by-Step Guide)
- Enter Your Room Dimensions: Measure the length, width, and height of your room.
- Select the Number of Coats: Standard coverage requires two coats, but darker colors may need more.
- Exclude Doors & Windows: A standard door is 21 sq ft, and a standard window is 15 sq ft.
- Adjust Paint Coverage (Optional): Default is 350 sq ft per gallon, but some brands vary.
- Click “Calculate” to get your estimate. Always round up to the nearest gallon to avoid running out of paint.
Paint Calculation Formula (How It Works)
Paint Coverage Chart (Estimate by Room Size)
| Room Size (Feet) | Coats | Gallons Needed |
| 10×10 | 2 | 1 gallon |
| 12×12 | 2 | 2 gallons |
| 15×15 | 2 | 2 gallons |
| 20×20 | 2 | 3-4 gallons |
| Full House | 2 | 10+ gallons |
For textured walls, add 10-15% more paint to your estimate.
Choosing the Right Paint for Your Walls
- Matte Paint – Ideal for ceilings and low-traffic areas.
- Satin Paint – Best for living rooms and bedrooms.
- Semi-Gloss or Gloss Paint – Great for kitchens and bathrooms due to its easy-to-clean finish.
Darker colors often require more coats, while lighter shades offer better coverage with fewer coats. If you’re planning to mix paints to create custom shades, you may also want to check what colors make brown for guidance on blending tones effectively.
How to Save Money on Paint
- Buy in bulk – A 5-gallon bucket is often cheaper per gallon.
- Use leftover paint – Save for small projects or touch-ups.
- Choose high-coverage paint – Some brands require fewer coats.
- Shop during sales – Many retailers offer discounts on paint supplies.
Recommended Paint Stores
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Frequently Asked Questions (FAQ)
How much paint do I need for a 12×12 room?
Two coats on a 12×12 room generally require 2 gallons of paint, excluding doors and windows.
Does wall texture affect paint coverage?
Yes. Rough or porous walls require 10-20% more paint than smooth surfaces.
Do I need to prime before painting?
Primer is recommended for bare drywall, dark-to-light color changes, and high-moisture areas.
Can I use leftover paint from another project?
Yes, but ensure the color and finish match for a seamless look.
How much does a gallon of paint cover?
A gallon of paint covers approximately 350 sq ft, but this varies by brand and paint type.
Start Your Painting Project Today
Now that you have an accurate paint estimate, it’s time to start painting.
- Use our Paint Calculator above to get your estimate.
- Buy the right amount of paint and avoid waste.
- Share this tool with friends planning a home improvement project.
Related Articles
- DIY Home Painting Tips for Beginners
- Best Paint Brands for Interior Walls
- How to Choose the Perfect Paint Color
