Construction & Building Calculators
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Paint Calculator
Calculation Mode
Wall Dimensions
Paint Settings
Area Calculations
Paint Requirements
Paint Can Breakdown
How We Calculate Paint Requirements
Step 1: Wall Area Calculation
We calculate the wall area by multiplying Length × Height: 10 × 10 = 100 sq ft
Step 2: Paintable Area
We subtract the area of doors and windows from the total wall area to get the actual paintable area.
Step 3: Paint Calculation
Paint required = (Paintable Area × Number of Coats) ÷ Paint Coverage per liter
Step 4: Can Optimization
We optimize the paint can combination to minimize waste and cost using 10L, 4L, and 1L cans.
- 10L Cans: 0 cans = 0L
- 4L Cans: 0 cans = 0L
- 1L Cans: 2 cans = 2L
Key Assumptions
- • Default paint coverage: 120 sq ft per liter
- • Average paint cost: ₹400 per liter
- • Standard door: ~21 sq ft (7' × 3')
- • Standard window: ~15 sq ft (5' × 3')
- • Premium paints may have higher coverage
Pro Tips
Paint Selection:
- • Premium paints offer better coverage
- • Consider primer for new walls
- • Dark colors may need extra coats
- • Buy 5-10% extra paint for touch-ups
Application Tips:
- • Use proper primer on new surfaces
- • Allow adequate drying time between coats
- • Use quality brushes and rollers
- • Apply thin, even coats
About This Paint Calculator
This calculator helps homeowners and painters figure out how much paint to buy for interior or exterior walls, whether you know the wall dimensions or just the total area. It accounts for number of coats, paint coverage rate, and deducts door and window area so you don't over- or under-order paint for your project.
Paint Calculator FAQs
How much paint do I need per square foot?
At the default coverage of 120 sq ft per liter, roughly 1 liter covers 120 sq ft per coat — this calculator lets you adjust the coverage rate for different paint brands and surface types.
Should I subtract door and window area?
Yes — this calculator deducts the area you specify for doors and windows from the total wall area to avoid overestimating paint requirements.
How many coats of paint should I apply?
Two coats is standard for most interior and exterior walls for even color and durability; a single coat may suffice for touch-ups, while three coats suit dark color changes.
How does the calculator optimize paint can sizes?
It greedily fills your total liter requirement using 10L cans first, then 4L, then 1L cans, to minimize the number of containers you need to buy.
Why might my actual paint usage differ from this estimate?
Rough or textured surfaces, dark color changes, and paint brand absorb more paint than the assumed 120 sq ft/liter coverage, so buying 5-10% extra is recommended.
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