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Use the paint calculation formula to buy exactly the right amount
Why Getting Your Paint Calculation Right Matters
Using a paint calculator before buying is the single best way to avoid the two most common mistakes Indian homeowners make: buying too little paint and running out mid-wall, or over-buying by 40% and wasting money. A precise paint calculation formula gives you the exact number of litres needed for every room — walls, ceilings, doors and trim included. Whether you are repainting a 1 BHK flat in Mumbai or a full independent house in Pune, this guide walks you through every step.
The Basic Paint Calculation Formula
The core paint calculation formula is straightforward:
Total Wall Area (sq ft) ÷ Coverage per Litre × Number of Coats = Litres Required
For example: a room with 500 sq ft of wall area, using a paint with 130 sq ft/litre coverage and applying 2 coats: 500 ÷ 130 × 2 = 7.7 litres. Round up to the nearest pack size — in this case two 4-litre tins.
Step 1 — Measure Your Wall Area
For each room, measure the perimeter (total length of all walls) and multiply by the ceiling height. Then subtract the area of doors (typically 21 sq ft each) and windows (typically 12–15 sq ft each).
Formula: (Perimeter × Height) − (Doors × 21) − (Windows × 13) = Net Paintable Area
Step 2 — Find the Coverage Rate
Every paint tin lists its theoretical coverage per litre. In practice, apply an 80% efficiency factor for textured or slightly rough Indian walls:
| Paint Type | Theoretical Coverage (sq ft/L) | Practical Coverage (sq ft/L) |
|---|---|---|
| Asian Paints Royale (Luxury Emulsion) | 140–160 | 110–130 |
| Asian Paints Tractor Emulsion | 130–150 | 105–120 |
| Asian Paints Apex Exterior | 110–130 | 88–104 |
| Birla Opus Primo Interior | 130–150 | 104–120 |
| Nerolac Impressions HD | 140–160 | 112–128 |
| Berger Silk | 130–150 | 104–120 |
| Texture / Putty | 30–50 | 25–40 |
Step 3 — Decide Number of Coats
For fresh plaster (new construction): 1 coat primer + 2 coats topcoat. For repainting over existing paint in good condition: 1 coat primer (optional) + 2 coats topcoat. For dark-to-light colour change: 1 coat primer + 3 coats topcoat.
Paint Quantity Calculator: Room-by-Room Guide for Indian Homes
Below are ready-to-use estimates for standard Indian room sizes. These use Asian Paints Royale at 120 sq ft/litre practical coverage, 2 coats, with standard door and window deductions.
| Room / Area | Approx Wall Area (sq ft) | Paint Required (litres) | Approx Cost (Royale, ₹) |
|---|---|---|---|
| Small bedroom (10×10 ft, 9 ft ceiling) | 300 | 5.0 | ₹2,200–2,500 |
| Master bedroom (12×14 ft, 9 ft ceiling) | 420 | 7.0 | ₹3,000–3,500 |
| Living room / hall (14×18 ft, 10 ft ceiling) | 580 | 9.7 | ₹4,200–4,800 |
| Kitchen (9×10 ft, 9 ft ceiling) | 240 | 4.0 | ₹1,700–2,000 |
| Bathroom (5×7 ft, 9 ft ceiling) | 130 | 2.2 | ₹950–1,200 |
| Full 2 BHK flat (700 sq ft) | 1,600 | 26.7 | ₹11,500–13,000 |
| Full 3 BHK flat (1,000 sq ft) | 2,200 | 36.7 | ₹16,000–18,500 |
How Much Paint Required for 500 Sq Ft Room?
This is one of the most-searched paint quantity questions in India. A room with 500 sq ft of gross wall area (before deductions for doors and windows) will require approximately 7–9 litres of interior emulsion for two coats at practical coverage rates. Here is the detailed breakdown:
- Net paintable area after deductions (2 doors, 2 windows): approximately 430 sq ft
- Coverage per litre (Tractor/Royale at practical rate): 120 sq ft/L
- Litres for 2 coats: 430 ÷ 120 × 2 = 7.2 litres
- Add 10% wastage buffer: 7.9 litres → buy 8 litres (two 4-litre tins)
Paint Calculation for Ceiling
Ceilings are often painted white or off-white with Asian Paints Tractor Emulsion Ceiling White. The calculation is simpler — measure floor area and that equals ceiling area. A 12×14 ft room has a 168 sq ft ceiling. At 130 sq ft/litre (one coat): 1.3 litres. Two coats: 2.6 litres. Most painters use 4 litres for a full 2 BHK ceiling (all rooms combined) at two coats.
A professional can verify your paint quantity before purchase
Primer Paint Quantity Calculation
Primer coverage is lower than topcoat because it penetrates the surface. Asian Paints Wall Primer covers approximately 80–100 sq ft per litre on smooth surfaces, and 50–70 sq ft per litre on rough or new plaster. For a 2 BHK flat with 1,600 sq ft of net wall area: 1,600 ÷ 90 = 18 litres of primer for one coat. Asian Paints Wall Primer is available in 10-litre and 20-litre drums — a 20-litre drum comfortably covers a full 2 BHK in one primer coat.
Paint Quantity by Paint Brand — Pack Sizes Available in India
| Brand / Product | Pack Sizes | Price Range per Litre (2026) | Best For |
|---|---|---|---|
| Asian Paints Royale (Code 0315 Ivory, 0336 Buttercup-N) | 1L, 4L, 10L, 20L | ₹380–450 | Bedrooms, living rooms |
| Asian Paints Tractor Emulsion | 4L, 10L, 20L | ₹180–220 | Budget interior walls |
| Asian Paints Apex Ultima (exterior) | 4L, 10L, 20L | ₹280–340 | Exterior walls |
| Birla Opus Primo Interior | 4L, 10L, 20L | ₹200–260 | Mid-range interior walls |
| Nerolac Impressions HD | 1L, 4L, 10L | ₹320–400 | Premium finish |
| Berger Silk | 1L, 4L, 10L | ₹300–380 | Smooth luxury finish |
Common Paint Calculation Mistakes to Avoid
Many Indian homeowners under-buy paint because they forget these three things. First, always add a 10–15% wastage buffer — rollers and brushes absorb paint, and colour matching is impossible if you run short. Second, never use theoretical coverage figures from the tin; always apply an 80% efficiency factor for real-world Indian walls which often have micro-texture and imperfections. Third, measure walls individually — do not estimate based on floor area, as ceiling height varies by room and floor in Indian construction.
A fourth common mistake is forgetting putty. Asian Paints Wall Putty or Birla Opus Wall Putty (applied before primer) consumes 2–3 kg per 100 sq ft. A 2 BHK flat typically needs 32–48 kg of wall putty. At ₹22–28 per kg, this adds ₹700–1,350 to your material budget — not a trivial amount.
Paint Cost Calculator: Labour + Material for Indian Cities (2026)
| City | Labour Rate (₹/sq ft) | Material (Royale, ₹/sq ft) | Total Approx (₹/sq ft) |
|---|---|---|---|
| Mumbai | ₹14–18 | ₹10–14 | ₹24–32 |
| Delhi / NCR | ₹12–16 | ₹10–14 | ₹22–30 |
| Bangalore | ₹13–17 | ₹10–14 | ₹23–31 |
| Hyderabad | ₹11–15 | ₹9–13 | ₹20–28 |
| Pune | ₹12–16 | ₹10–14 | ₹22–30 |
| Chennai | ₹12–15 | ₹9–13 | ₹21–28 |
| Tier-2 cities | ₹9–13 | ₹8–12 | ₹17–25 |
Frequently Asked Questions — Paint Calculator
How do I calculate how much paint I need for a wall?
Measure the wall’s width and height, multiply to get square footage, then divide by the paint’s practical coverage (usually 100–130 sq ft per litre for interior emulsion). Multiply by the number of coats. Add 10–15% for wastage.
What is the paint calculation formula for Indian walls?
Net wall area (sq ft) ÷ Practical coverage (sq ft/litre) × Number of coats = Litres needed. Use 80% of the tin’s stated coverage to account for Indian wall texture and absorption.
How much paint is required for 500 sq ft of wall area?
Approximately 7–8 litres of interior emulsion for two coats at 120 sq ft/litre practical coverage. Buy two 4-litre tins (8 litres) to include a safety buffer.
What is the coverage of Asian Paints Royale per litre?
Asian Paints Royale has a theoretical coverage of 140–160 sq ft per litre. In practice on Indian walls, expect 110–130 sq ft per litre. Use 120 sq ft/litre as a safe calculation base.
How many litres of paint for a 2 BHK flat?
A standard 700–800 sq ft 2 BHK has approximately 1,500–1,700 sq ft of net wall area. At two coats: 25–28 litres of interior emulsion plus 18–22 litres of primer for one coat.
How many litres of paint for a 3 BHK flat?
A 1,000–1,200 sq ft 3 BHK has approximately 2,100–2,500 sq ft of net wall area. Expect 35–42 litres of interior emulsion at two coats plus 22–28 litres of primer.
How do I calculate paint for a ceiling?
Ceiling area equals floor area. Measure length × width of the room. Divide by the paint’s coverage (Ceiling White: 130–150 sq ft/litre) and multiply by 2 for two coats.
How much paint calculator: does texture need more paint?
Yes. Texture paint covers only 30–50 sq ft per litre compared to 120–140 sq ft for emulsion. Asian Paints Royal Play texture paste covers approximately 35 sq ft per litre. Budget 2–3× more quantity for textured finishes.
Should I add wastage to my paint calculation?
Always add 10–15% wastage. This covers roller absorption (rollers hold 100–200 ml of paint), brush edges, surface irregularities, and touch-up needs after the main job is complete.
What is the paint quantity formula for doors and windows?
Subtract doors (≈21 sq ft each) and windows (≈13 sq ft each) from total wall area. Then if you are painting doors separately with Asian Paints Wood Finish or Enamel, add door area back at enamel coverage rates (80–100 sq ft/litre for enamel).
Get a Free Paint Estimate from AapkaPainter
Calculating paint quantity is just the first step. AapkaPainter’s professional painters will visit your home, take precise measurements, recommend the right Asian Paints or Birla Opus product for your walls, and give you a fixed-price quote covering both material and labour. No surprises, no over-buying. AapkaPainter serves Mumbai, Delhi, Bangalore, Hyderabad, Pune, Chennai, Noida, Gurgaon, Faridabad and other cities across India.