Paint Calculator
Calculate how much paint you need for your painting project. Choose from single walls, entire rooms, ceilings, doors, or windows. Enter dimensions, number of coats, and exclusions to get accurate paint estimates with waste allowance.
Project Details
How to Use the Paint Calculator
- Add areas using the "Add Area" button for multiple surfaces to paint
- Choose your project type: Single Wall, Entire Room, Ceiling, Doors, or Windows
- Enter dimensions based on your selected project type
- Set number of coats, doors/windows to exclude, and waste percentage
- Optionally enter paint coverage and cost for shopping estimates
- Click "Calculate" to get total area, paint needed, and cost
Areas to Paint
Areas to Exclude
Quick Exclude (Standard Sizes)
Additional Options
How Much Paint Do You Really Need?
Whether you're painting a single accent wall or an entire room, getting the right amount of paint is crucial. Too little, and you'll need to run back to the store mid-project. Too much, and you've wasted money on leftovers you'll never use.
Our Paint Calculator helps you estimate exactly how many gallons or liters you need — based on your room size, wall height, number of coats, and even doors or windows you want to subtract.
🧮 How to Calculate Paint Coverage
Most paint cans list their coverage rate on the label — usually around 350 to 400 square feet per gallon (or 10–12 m² per liter). That rate assumes:
- A smooth, non-porous surface
- One coat of quality paint
Use this formula if doing it manually:
Or skip the math — just plug your values into our calculator.
🛠️ Common Paint Coverage Estimates (Per Gallon)
| Surface Type | 1 Coat Coverage (U.S. Gallon) | Notes |
|---|---|---|
| Smooth drywall | 350–400 ft² | Ideal conditions |
| Textured walls | 250–300 ft² | Requires more paint |
| Fresh drywall | 300–350 ft² | May soak up more |
| Ceilings | 350 ft² | Typically one coat |
| Exterior surfaces | 250–300 ft² | Depends on siding type |
🧱 What Surfaces Are You Painting?
Paint needs can vary depending on surface type:
- New drywall may require primer + more coats
- Dark-to-light color changes usually need extra coats
- Textured walls or stucco absorb more paint
- Exterior surfaces may need weather-resistant formulas
🧍 Single Wall vs. Whole Room — Which to Choose?
Our calculator supports both:
This flexibility helps DIYers, homeowners, and contractors get precise estimates for any job.
🪣 Paint Unit Conversions
Our tool shows results in gallons and liters, so you're covered no matter where you live.
| Unit | Equivalent |
|---|---|
| 1 gallon | 3.785 liters |
| 1 liter | 0.264 gallons |
| 1 quart | 0.946 liters |
| 1 pint | 0.473 liters |
🎯 Pro Tips to Avoid Over- or Underbuying
- Always round up slightly — leftover paint is good for touch-ups
- Buy from the same batch to avoid color variations
- Store leftovers in airtight containers away from sunlight
- Use primer to reduce the number of coats needed
Why Use a Paint Calculator?
Our paint calculator helps you determine the exact amount of paint needed for your painting project. Avoid over-buying or running out mid-project by getting an accurate estimate based on your area dimensions and coverage requirements.
Key Features:
- Calculate paint amounts for multiple areas and surfaces
- Support for walls, ceilings, doors, and windows
- Account for multiple coats and waste allowance
- Exclude doors and windows automatically
- Cost estimation and budget planning
Common Painting Projects We Support
Our calculator is ideal for:
- Interior wall painting projects
- Ceiling painting and touch-ups
- Complete room makeovers
- Door and window trim painting
- Multi-room painting projects
How Paint Volume is Calculated
We calculate the total paint needed using:
Results are provided in both gallons and liters with:
- Paint volume needed in gallons and liters
- Cost estimates when price is provided
- Area-by-area breakdown for planning
- Waste allowance calculations
Pro Tips for Paint Estimation
- Use 2 coats for most interior painting projects
- Add 10-15% waste allowance for touch-ups and mistakes
- Consider primer if changing colors dramatically
- Account for texture - textured surfaces need more paint
- Buy slightly more than calculated to ensure color consistency
- Check paint coverage rates on the can for accuracy
Frequently Asked Questions About Paint:
- How much paint do I need for a room?
- How to calculate paint for multiple rooms?
- Should I include doors and windows in calculations?
- How many coats of paint should I apply?
- What's the best paint coverage for my project?
- How to estimate paint cost for budgeting?
- Do I need primer before painting?
- How much waste allowance should I add?