Free Paint Calculator – Accurately Estimate Paint Quantity
Quickly calculate the amount of paint needed for walls, ceilings, and rooms of any size
Use this Paint Calculator to accurately determine how much paint you need for your interior or exterior painting projects. Simply enter the dimensions of your walls or surfaces, specify the number of coats, and the tool calculates the exact quantity required, helping you avoid over-purchasing or running out of paint mid-project.
Ideal for homeowners, painters, contractors, and DIY enthusiasts, this calculator saves time, reduces waste, and ensures precise planning. Get instant, reliable estimates for gallons, liters, or any preferred unit — no registration or downloads required.
Why Use a Paint Calculator?
Using a paint calculator helps you plan your painting project more effectively by providing accurate estimates of how much paint you'll need. This prevents overbuying (saving money) or underbuying (avoiding multiple trips to the store). Our calculator takes into account room dimensions, doors, windows, and the number of coats you plan to apply.
How to Calculate Paint Needed
Calculating paint requirements involves several steps:
- Measure the length, width, and height of your room
- Calculate the total wall surface area (perimeter × height)
- Subtract the area of doors and windows
- Check your paint's coverage rate (usually on the paint can)
- Determine how many coats you'll need
- Divide the paintable area by the coverage rate, then multiply by the number of coats
Factors Affecting Paint Calculation
Several factors can affect how much paint you'll need:
- Surface texture: Rough or textured surfaces may require more paint
- Paint quality: Higher quality paints often have better coverage
- Color changes: Painting a light color over a dark one may need additional coats
- Application method: Rollers typically use less paint than brushes
- Surface condition: Unprimed or porous surfaces absorb more paint
Tips & FAQs
How much extra paint should I buy?
It's recommended to purchase 10% extra paint to account for touch-ups and mistakes. For small projects, rounding up to the next whole can is usually sufficient.
Do I need to prime before painting?
Priming is recommended when painting over a dark color with a light one, painting on new drywall, or covering stains. Primer helps paint adhere better and can reduce the number of paint coats needed.
How do I calculate paint for a ceiling?
To calculate paint for a ceiling, multiply the room length by width to get the ceiling area. Then divide by the paint coverage rate. Ceilings typically require fewer coats than walls.
What's the difference between paint types?
Different paint finishes (matte, eggshell, satin, semi-gloss, gloss) have different coverage rates and durability. Glossier paints typically cover less area but are more durable and easier to clean.
How can I make my paint last longer?
Proper surface preparation, using quality paint, applying appropriate coats, and allowing adequate drying time between coats will help ensure your paint job lasts longer.
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