Paint Calculator
Calculate how much paint you need for your project. Enter the dimensions of your walls and we'll estimate the amount of paint required, including extra for multiple coats and waste.
Paint Coverage Information
The default coverage rate is set to 400 sq ft per gallon, which is typical for most interior paints. This may vary based on:
- Paint quality and type
- Surface texture and porosity
- Application method
Paint Requirements
Total Wall Area
Net Paintable Area
Paint Needed
Pro Tips
- Purchase slightly more paint than calculated to ensure you have enough for touch-ups
- Consider using primer on new or dark surfaces
- Clean walls thoroughly before painting for best results
Understanding Paint Coverage
Paint coverage varies based on several factors including paint quality, surface type, application method, and color changes. Standard interior paint typically covers 350-400 square feet per gallon on smooth, primed surfaces. Rough or porous surfaces like bare wood, concrete, or textured walls may require 20-30% more paint. Primer should be used on new drywall, patched areas, or when making dramatic color changes. Multiple coats are often needed for best results, especially when painting over dark colors or using lighter shades.
Paint Coverage Factors
- Surface Type: Smooth drywall requires less paint than textured or porous surfaces
- Paint Quality: Higher quality paints often provide better coverage with fewer coats
- Application Method: Spraying typically uses more paint than brushing or rolling
- Color Change: Going from dark to light colors requires more coats than similar shades
- Surface Preparation: Properly primed and prepared surfaces need less paint
- Paint Sheen: Flat paints typically cover better than glossy finishes
Painting Best Practices
Surface Preparation
- • Clean walls to remove dirt, grease, and dust
- • Fill holes and cracks with spackling compound
- • Sand rough areas smooth
- • Apply primer to bare surfaces or stains
- • Remove outlet covers and tape edges
- • Protect floors and furniture with drop cloths
Application Tips
- • Use quality brushes and rollers for best results
- • Cut in edges before rolling larger areas
- • Apply thin, even coats rather than thick ones
- • Maintain a wet edge to avoid lap marks
- • Allow proper drying time between coats
- • Paint in consistent lighting conditions
Paint Selection
- • Choose appropriate sheen for the room
- • Flat/Matte: Best for low-traffic areas, hides imperfections
- • Eggshell/Satin: Good for living areas, easy to clean
- • Semi-gloss: Ideal for trim, kitchens, bathrooms
- • High-gloss: Best for doors, cabinets, high-traffic areas
- • Consider washability and durability needs
Common Mistakes to Avoid
- • Skipping surface preparation steps
- • Not using primer when needed
- • Applying too thick coats
- • Painting in extreme temperatures or humidity
- • Using cheap brushes and rollers
- • Not allowing adequate drying time between coats
Standard Door and Window Sizes
This calculator uses standard sizes to estimate the area taken up by doors and windows:
Standard Door
Approximately 20 square feet (typical door size: 3' x 7')
Standard Window
Approximately 15 square feet (typical window size: 3' x 5')
Note: This calculator provides estimates based on standard paint coverage rates and typical door/window sizes. Actual paint requirements may vary depending on surface condition, paint quality, application method, and specific project requirements. Always purchase slightly more paint than calculated to account for variations and have enough for future touch-ups. For large or complex projects, consult with a professional painter or paint retailer for more accurate estimates.