Paint Calculator
Calculate how much paint you need
Room Dimensions
Average window: 15 sq ft
Average door: 20 sq ft
Most rooms need 2 coats
How to Use This Calculator
Select Measurement Unit
Choose your preferred unit (feet or meters) for room dimensions. The calculator will handle conversions automatically.
Enter Room Dimensions
Input the length, width, and height of each room you want to paint. Add multiple rooms by clicking "Add Room" button.
Specify Windows and Doors
Enter the number of windows (15 sq ft each) and doors (20 sq ft each) so the calculator can subtract these areas automatically.
Select Number of Coats
Choose how many coats you'll apply. Most rooms need 2 coats for good coverage. Fresh drywall or dark colors may need 3 coats.
Calculate Paint Needs
Click "Calculate Paint Needed" to see gallons required, total area, and estimated cost. Order slightly more than calculated for touch-ups.
Formula
Wall Area = 2 × (Length + Width) × Height
Painable Area = Wall Area - (Windows × 15) - (Doors × 20)
Total Area to Paint = Painable Area × Number of Coats
Gallons Needed = Total Area to Paint ÷ 350
Example 1: Single Room (12 ft × 10 ft × 8 ft, 2 windows, 1 door, 2 coats)
Step 1: Calculate wall area: 2 × (12 + 10) × 8 = 2 × 22 × 8 = 352 sq ft
Step 2: Subtract openings: 352 - (2 × 15) - (1 × 20) = 352 - 30 - 20 = 302 sq ft
Step 3: Apply coats: 302 × 2 = 604 sq ft to paint
Step 4: Calculate gallons: 604 ÷ 350 = 1.73 gallons → 2 gallons
Example 2: Multiple Rooms (Two 12×10×8 rooms, 4 windows, 2 doors, 2 coats)
Step 1: Room 1 area: 2 × (12 + 10) × 8 = 352 sq ft
Step 2: Room 2 area: 2 × (12 + 10) × 8 = 352 sq ft
Step 3: Total wall area: 352 + 352 = 704 sq ft
Step 4: Subtract openings: 704 - (4 × 15) - (2 × 20) = 704 - 60 - 40 = 604 sq ft
Step 5: Apply coats: 604 × 2 = 1,208 sq ft
Step 6: Calculate gallons: 1,208 ÷ 350 = 3.45 gallons → 4 gallons
Paint Coverage Guide
Paint Types & Finishes
Flat/Matte
Best for low-traffic areas, ceilings. Hides imperfections. Hard to clean.
Eggshell
Slight sheen. Good for living rooms, bedrooms. Easier to clean than flat.
Satin
Velvety finish. Great for high-traffic areas, kitchens, bathrooms. Durable.
Semi-Gloss/Gloss
Shiny finish. Best for trim, doors, cabinets. Very durable and washable.
Painting Tips
Preparation
- Clean walls thoroughly (dirt prevents adhesion)
- Fill holes and cracks with spackle
- Sand smooth after spackle dries
- Use primer on new drywall or dramatic color changes
- Remove switch plates and outlet covers
Application
- Cut in (edges) first with brush, then roll
- Use quality brushes and rollers (makes huge difference)
- Paint in W or M pattern for even coverage
- Let first coat dry completely before second coat
- Paint ceiling first, then walls, then trim
How Many Coats?
- Fresh drywall: Primer + 2 coats paint
- Light color over dark: 2-3 coats
- Same/similar color: 1-2 coats
- Dark color over light: 2 coats usually enough
About Paint Calculator
The Paint Calculator is a useful tool for calculating paint values. This calculator helps you quickly and accurately determine the results you need for your calculations.
When to Use This Calculator
- Quick Calculations: Get instant results without manual computation
- Accuracy: Ensure precise calculations every time
- Planning: Use for project planning and estimation
- Verification: Double-check your manual calculations
Why Use Our Calculator?
- ✅ Instant Results: Get accurate calculations immediately
- ✅ Easy to Use: Simple interface for all skill levels
- ✅ 100% Free: No registration or payment required
- ✅ Mobile Friendly: Works on all devices
- ✅ Accurate: Precise mathematical calculations
Tips for Best Results
- Double-Check Inputs: Verify all values before calculating
- Use Valid Numbers: Ensure inputs are valid numbers
- Review Results: Check results for reasonableness
- Clear and Retry: Clear inputs if you need to recalculate
Frequently Asked Questions
About Paint Calculator
The Paint Calculator is a useful tool for calculating paint values. This calculator helps you quickly and accurately determine the results you need for your calculations.
When to Use This Calculator
- Quick Calculations: Get instant results without manual computation
- Accuracy: Ensure precise calculations every time
- Planning: Use for project planning and estimation
- Verification: Double-check your manual calculations
Why Use Our Calculator?
- ✅ Instant Results: Get accurate calculations immediately
- ✅ Easy to Use: Simple interface for all skill levels
- ✅ 100% Free: No registration or payment required
- ✅ Mobile Friendly: Works on all devices
- ✅ Accurate: Precise mathematical calculations
Tips for Best Results
- Double-Check Inputs: Verify all values before calculating
- Use Valid Numbers: Ensure inputs are valid numbers
- Review Results: Check results for reasonableness
- Clear and Retry: Clear inputs if you need to recalculate
How much does a gallon of paint cost?
$20-40 for quality paint. Budget: $15-25, Mid-range: $30-40, Premium: $50-70. Higher quality paint covers better and lasts longer.
Do I need primer?
Yes if: new drywall, dramatic color change, stained/damaged walls, porous surfaces. No if: same/similar color, good condition walls.
How long does paint last?
Unopened: 10 years if stored properly. Opened: 2-5 years. Interior paint job: 5-10 years depending on traffic and quality.
Can I paint over wallpaper?
Not recommended. Wallpaper can peel, causing paint to peel. Best to remove wallpaper first. If you must, use oil-based primer first.
What's the difference between cheap and expensive paint?
Coverage (expensive = fewer coats), durability (lasts longer), ease of application (flows better), color retention (doesn't fade). Worth paying more!