Paint Calculator & Wall Area Estimator
Calculate paint volume (litres), primer requirements, and complete project budget with wall area and opening deductions.
Room Dimensions
Recommended Commercial Can Packaging
Project Cost Estimate ₹12,690
How to Accurately Estimate Wall Area & Paint Quantity
Calculating the exact paint requirement prevents costly mid-project shortages or unnecessary excess paint cans. To compute net paintable wall area, calculate the 4 vertical wall perimeters, add the ceiling surface (if scheduled for painting), and deduct openings like doors, windows, and built-in wardrobes.
Wall & Ceiling Surface Formulas
Standard Architectural Opening Sizes
- Standard Room Door: 3 ft × 7 ft = 21 sq.ft (1.95 sq.m)
- Double Window: 4 ft × 3 ft = 12 sq.ft (1.11 sq.m)
- Balcony French Door: 5 ft × 7 ft = 35 sq.ft (3.25 sq.m)
- Wastage / Spill Factor: Professional painters typically add a 5% to 10% safety buffer for roller spatter and absorbent surfaces.
Paint Types, Finish & Spreading Rate Benchmarks
| Paint Grade & Type | Finish | 1 Coat Coverage | 2 Coats Coverage | Ideal Application |
|---|---|---|---|---|
| Luxury Emulsion (Royale/Velvet) | Soft Sheen / Silk | 260–290 sq.ft/L | 130–150 sq.ft/L | Living rooms, master bedrooms |
| Premium Acrylic Emulsion | Eggshell / Matte | 220–240 sq.ft/L | 110–125 sq.ft/L | Standard bedrooms, hallways |
| Acrylic Distemper | Flat Chalky | 150–170 sq.ft/L | 75–90 sq.ft/L | Ceilings, rental turnarounds |
| Exterior Weathercoat | Satin / Textured | 120–140 sq.ft/L | 60–75 sq.ft/L | External facade, boundary walls |
Frequently Asked Questions (FAQ)
Why is a primer coat necessary before painting?
Primer seals porous wall putty or plaster, promotes uniform color adhesion, prevents chemical leaching (efflorescence), and prevents drywall from absorbing expensive topcoat paint unevenly.
How many coats of paint are needed when switching from dark to light walls?
When painting a lighter color (such as off-white or beige) over a darker base (such as deep blue or red), use 1 coat of high-opacity primer followed by 3 thin topcoats for solid hide and streak-free finish.
How much water should be added to dilute emulsion paint?
Most water-based interior emulsion paints require 300 ml to 400 ml of clean water per 1 litre of paint (30%–40% dilution). Over-thinning causes drip runs and poor opacity.