Free Construction Tool
Paint Quantity Calculator.
Enter your room dimensions to instantly calculate how many litres of paint, primer and putty you need — for interior or exterior walls. No guesswork, no wastage.
Room Dimensions
Deduct From Paintable Area
doors
windows
Paint Type
Number of Coats
Include Primer / Putty?
Your Paint Estimate
Fill in room dimensions and click Calculate to see your paint and primer requirements.
Results will appear here once you enter your room dimensions and press Calculate.
How to Use This Calculator
1
Enter RoomsAdd length, width and height for each room or space to be painted, in feet.
2
Set DeductionsDoors (21 sqft) and windows (12 sqft) are automatically deducted from paintable area.
3
Pick Paint GradeSelect paint type — coverage per litre varies from 68 to 160 sqft/L by product grade.
4
Get ResultsInstantly see litres needed, can pack sizes, primer and putty quantities with wastage buffer.
The Formula
Paint Calculation Formula Explained.
The standard method for estimating paint quantity divides your total paintable wall area by the paint’s coverage rate, multiplied by number of coats. Here is how to apply it step by step, with a worked example.
Standard Paint Quantity Formula
Paint (litres) = Paintable Area (sqft) ÷ Coverage per litre (sqft/L) × No. of Coats
Paintable Area = Total wall area − door areas − window areas (+ ceiling area if painting ceiling)
Total Wall Area = 2 × (Room Length + Room Width) × Ceiling Height
Coverage per litre = As specified on paint tin; typically 120–160 sqft/L for interior emulsions (single coat)
No. of Coats = 1 for light repaint · 2 for new construction · 3 for colour change
Add 10% wastage to the final litres before purchasing
Total Wall Area = 2 × (Room Length + Room Width) × Ceiling Height
Coverage per litre = As specified on paint tin; typically 120–160 sqft/L for interior emulsions (single coat)
No. of Coats = 1 for light repaint · 2 for new construction · 3 for colour change
Add 10% wastage to the final litres before purchasing
1
Measure Wall Area
Total wall area = 2 × (Length + Width) × Height. Calculate each room separately and add together.
2
Deduct Openings
Subtract doors (~21 sqft each) and windows (~12 sqft each). Measure your actual openings for precision.
3
Divide by Coverage
Divide paintable area by the single-coat coverage rate. Multiply by number of coats to get total litres.
4
Add 10% Wastage
Multiply the result by 1.10. This covers surface unevenness, brush waste and touch-ups.
📐 Worked Example — 15 ft × 12 ft bedroom, 10 ft ceiling, Premium Emulsion, 2 coats, 2 doors + 3 windows
Total wall area2 × (15 + 12) × 10540 sqft
Less: 2 doors (2 × 21 sqft)2 × 3 ft × 7 ft− 42 sqft
Less: 3 windows (3 × 12 sqft)3 × 3 ft × 4 ft− 36 sqft
Net paintable area540 − 42 − 36462 sqft
Paint for 2 coats @ 140 sqft/L462 ÷ (140 ÷ 2) = 462 ÷ 706.6 litres
Add 10% wastage buffer6.6 × 1.107.3 litres
Primer (1 coat @ 175 sqft/L)462 ÷ 175 × 1.05~2.8 litres
✅ Total to Purchase1×4L paint + 1×4L paint~10 litres total
Quick Reference
Paint Coverage Rates by Type & Surface.
Coverage rates vary by paint grade, number of coats and surface condition. The table below shows standard values used in Indian construction projects for estimating paint quantity.
| Paint Type | Coverage (1 Coat) | Coverage (2 Coats effective) | Litres per 1,000 sqft (2 coats) | Typical Use | Surface |
|---|---|---|---|---|---|
| Economy Emulsion | 110–120 sqft/L | 55–60 sqft/L | ~17–18 litres | Budget repaints, rental properties | Interior |
| Premium Emulsion | 130–140 sqft/L | 65–70 sqft/L | ~14–15 litres | Residential, commercial interiors | Interior |
| Luxury / Sheen Matt | 150–160 sqft/L | 75–80 sqft/L | ~13 litres | High-end residential, showrooms | Interior |
| Texture Paint | 70–90 sqft/L | 35–45 sqft/L | ~22–28 litres | Feature walls, designer finishes | Interior |
| Exterior Emulsion | 110–120 sqft/L | 55–60 sqft/L | ~17–18 litres | Standard exterior walls | Exterior |
| Premium Exterior | 130–140 sqft/L | 65–70 sqft/L | ~14–15 litres | Weather-resistant residential | Exterior |
| Acrylic / Elastomeric | 90–100 sqft/L | 45–50 sqft/L | ~20–22 litres | Waterproof coating, terrace walls | Exterior |
| Exterior Texture | 60–75 sqft/L | 30–37 sqft/L | ~27–33 litres | Decorative façades | Exterior |
Standard Deduction Areas
Single Door (3 × 7 ft)21 sqft
Double Door (5 × 7 ft)35 sqft
Standard Window (3 × 4 ft)12 sqft
Large Window (4 × 5 ft)20 sqft
Ventilator (1.5 × 2 ft)3 sqft
Typical 2BHK all openings~120–140 sqft
Primer Coverage Rates
Wall Primer (1 coat)150–200 sqft/L
New walls — coats needed1–2 coats
Repaint — coats needed1 coat
1,000 sqft new surface~11–13 litres
1,000 sqft repaint~5–7 litres
Wastage factor+5%
Wall Putty Consumption
1 coat @ 1 mm thick1–1.2 kg / 100 sqft
2 coats (standard finish)2–2.5 kg / 100 sqft
40 kg bag (1 coat)~3,000–4,000 sqft
5 kg bag (1 coat)~400–500 sqft
Drying time between coats4–6 hours
Wastage factor+5–10%
Room Reference
How Much Paint for Common Room Sizes?
Reference values for standard Indian room sizes. Assumes 10 ft ceiling, 2 doors + 2 windows per room, Premium Emulsion at 140 sqft/litre, 2 coats, 10% wastage included.
| Room Type | Dimensions | Total Wall Area | Paintable Area | Paint (2 coats) | Primer (1 coat) | Putty (2 coats) |
|---|---|---|---|---|---|---|
| Small Bedroom | 10 × 10 ft, 10 ft ht | 400 sqft | ~358 sqft | ~5.6 litres | ~2.1 litres | ~7 kg |
| Standard Bedroom | 12 × 10 ft, 10 ft ht | 440 sqft | ~394 sqft | ~6.2 litres | ~2.3 litres | ~8 kg |
| Master Bedroom | 15 × 12 ft, 10 ft ht | 540 sqft | ~462 sqft | ~7.3 litres | ~2.7 litres | ~9.5 kg |
| Living Room | 18 × 14 ft, 10 ft ht | 640 sqft | ~544 sqft | ~8.5 litres | ~3.2 litres | ~11 kg |
| Kitchen | 10 × 8 ft, 10 ft ht | 360 sqft | ~310 sqft | ~4.9 litres | ~1.8 litres | ~6.5 kg |
| 2BHK Full Flat | ~800–900 sqft carpet | ~2,200 sqft | ~1,900 sqft | ~30 litres | ~11 litres | ~40 kg |
| 3BHK Full Flat | ~1,100–1,300 sqft carpet | ~3,000 sqft | ~2,600 sqft | ~41 litres | ~15 litres | ~55 kg |
Wastage Factor Guidelines
New smooth plaster surface+5%
Standard repaint+8–10%
Rough / uneven surface+10–15%
Textured finish application+15–20%
Spray application+20–25%
Complex shapes / arches+15–20%
Number of Coats — When to Use
1 coatLight repaint, same colour
2 coatsNew construction (standard)
2 coatsColour change, similar shade
3 coatsDark → light colour change
3 coatsStained or damaged walls
IS code referenceIS 428 / IS 5410
FAQs
Frequently Asked Questions About Paint Calculation.
Common questions about calculating paint quantity, coverage rates, primer, putty and wastage for construction and renovation projects in India.
How do you calculate paint quantity for a room?+
Paint quantity = Paintable Area ÷ Coverage per litre × Number of coats, then add 10% wastage.
Step 1 — Calculate total wall area: 2 × (Length + Width) × Height.
Step 2 — Subtract door areas (21 sqft each) and window areas (12 sqft each).
Step 3 — Divide by coverage rate (120–160 sqft per litre for interior emulsions).
Step 4 — Multiply by number of coats. Add 10% for wastage.
Example: 15 × 12 ft room, 10 ft ceiling, 2 doors, 3 windows, premium emulsion (140 sqft/L), 2 coats:
Wall area = 540 sqft. Deduct 42 + 36 = 78 sqft → Paintable area = 462 sqft.
Paint = 462 ÷ 70 = 6.6 litres. Add 10% → ~7.3 litres.
Step 1 — Calculate total wall area: 2 × (Length + Width) × Height.
Step 2 — Subtract door areas (21 sqft each) and window areas (12 sqft each).
Step 3 — Divide by coverage rate (120–160 sqft per litre for interior emulsions).
Step 4 — Multiply by number of coats. Add 10% for wastage.
Example: 15 × 12 ft room, 10 ft ceiling, 2 doors, 3 windows, premium emulsion (140 sqft/L), 2 coats:
Wall area = 540 sqft. Deduct 42 + 36 = 78 sqft → Paintable area = 462 sqft.
Paint = 462 ÷ 70 = 6.6 litres. Add 10% → ~7.3 litres.
How many litres of paint do I need per square foot?+
For 2 coats of standard interior emulsion paint, you need approximately 1 litre per 60–70 sqft (0.014–0.017 litres per sqft).
By paint grade (2 coats):
— Economy emulsion: ~1 litre per 55–60 sqft
— Premium emulsion: ~1 litre per 65–70 sqft
— Luxury matt: ~1 litre per 75–80 sqft
— Texture paint: ~1 litre per 35–45 sqft
Always verify coverage on the paint tin — actual coverage varies by brand, applicator and surface porosity.
By paint grade (2 coats):
— Economy emulsion: ~1 litre per 55–60 sqft
— Premium emulsion: ~1 litre per 65–70 sqft
— Luxury matt: ~1 litre per 75–80 sqft
— Texture paint: ~1 litre per 35–45 sqft
Always verify coverage on the paint tin — actual coverage varies by brand, applicator and surface porosity.
How do I calculate exterior paint quantity?+
For exterior walls: Total wall area = Perimeter × Wall Height (from plinth to roof level).
Subtract all external window and door openings. Exterior paints typically cover 100–140 sqft per litre per coat. Use 2 coats as standard and add 10–15% wastage since exterior surfaces are more porous and uneven.
Example: 30 × 25 ft building, 12 ft height:
Perimeter = 110 ft. Wall area = 110 × 12 = 1,320 sqft. Deduct 6 windows + 2 doors = 114 sqft → Paintable = 1,206 sqft.
At 120 sqft/L, 2 coats: 1,206 ÷ 60 = ~20 litres + 15% = ~23 litres.
Subtract all external window and door openings. Exterior paints typically cover 100–140 sqft per litre per coat. Use 2 coats as standard and add 10–15% wastage since exterior surfaces are more porous and uneven.
Example: 30 × 25 ft building, 12 ft height:
Perimeter = 110 ft. Wall area = 110 × 12 = 1,320 sqft. Deduct 6 windows + 2 doors = 114 sqft → Paintable = 1,206 sqft.
At 120 sqft/L, 2 coats: 1,206 ÷ 60 = ~20 litres + 15% = ~23 litres.
How much primer do I need for painting walls?+
Wall primer typically covers 150–200 sqft per litre per coat. For new plastered surfaces apply 1–2 coats. For repaints over good existing paint, 1 coat is usually enough.
Formula: Primer litres = Paintable Area ÷ 175 × number of coats × 1.05
For a 2BHK flat (~1,900 sqft paintable area):
— New construction (2 coats): 1,900 ÷ 175 × 2 × 1.05 = ~22 litres
— Repaint (1 coat): 1,900 ÷ 175 × 1.05 = ~11 litres
Formula: Primer litres = Paintable Area ÷ 175 × number of coats × 1.05
For a 2BHK flat (~1,900 sqft paintable area):
— New construction (2 coats): 1,900 ÷ 175 × 2 × 1.05 = ~22 litres
— Repaint (1 coat): 1,900 ÷ 175 × 1.05 = ~11 litres
How much wall putty is needed per square foot?+
Wall putty consumption: approximately 1–1.5 kg per 100 sqft per coat at 1 mm application thickness. For a standard 2-coat finish, budget 2–2.5 kg per 100 sqft.
Can size reference:
— 40 kg bag: ~3,000–4,000 sqft for 1 coat
— 20 kg bag: ~1,500–2,000 sqft for 1 coat
— 5 kg bag: ~400–500 sqft for 1 coat
Allow 4–6 hours drying time between coats. Add 5% extra for wastage and thick patches near corners.
Can size reference:
— 40 kg bag: ~3,000–4,000 sqft for 1 coat
— 20 kg bag: ~1,500–2,000 sqft for 1 coat
— 5 kg bag: ~400–500 sqft for 1 coat
Allow 4–6 hours drying time between coats. Add 5% extra for wastage and thick patches near corners.
What is the standard door and window area used for paint deductions?+
Standard deduction areas used in Indian construction estimates:
— Standard door: 3 ft × 7 ft = 21 sqft per door
— Double door: 5 ft × 7 ft = 35 sqft
— Standard window: 3 ft × 4 ft = 12 sqft per window
— Large window: 4 ft × 5 ft = 20 sqft
— Ventilator: 1.5 ft × 2 ft = 3 sqft
For precise estimates, always measure your actual opening sizes. The figures above are standard values used for quick estimation in BOQ and tender documents.
— Standard door: 3 ft × 7 ft = 21 sqft per door
— Double door: 5 ft × 7 ft = 35 sqft
— Standard window: 3 ft × 4 ft = 12 sqft per window
— Large window: 4 ft × 5 ft = 20 sqft
— Ventilator: 1.5 ft × 2 ft = 3 sqft
For precise estimates, always measure your actual opening sizes. The figures above are standard values used for quick estimation in BOQ and tender documents.
How many coats of paint are needed for new construction?+
For new construction in India, the standard sequence is:
1. Wall putty — 1 to 2 coats for a smooth, fillable surface
2. Primer — 1 to 2 coats to seal the surface and improve topcoat adhesion
3. Topcoat paint — 2 coats standard; 3 coats for premium finish or colour change from dark to light
For repainting: 1 coat primer + 2 coats topcoat is standard. Always follow the paint manufacturer’s data sheet for recommended coat thickness and drying intervals (typically 4–6 hours between coats).
1. Wall putty — 1 to 2 coats for a smooth, fillable surface
2. Primer — 1 to 2 coats to seal the surface and improve topcoat adhesion
3. Topcoat paint — 2 coats standard; 3 coats for premium finish or colour change from dark to light
For repainting: 1 coat primer + 2 coats topcoat is standard. Always follow the paint manufacturer’s data sheet for recommended coat thickness and drying intervals (typically 4–6 hours between coats).
पेंट की मात्रा कैसे निकालें? (Paint calculation formula in Hindi)+
पेंट की मात्रा निकालने का फार्मूला:
पेंट (लीटर) = पेंटेबल क्षेत्र (sqft) ÷ प्रति लीटर कवरेज × कोट की संख्या
चरण 1: दीवार क्षेत्र = 2 × (लंबाई + चौड़ाई) × ऊंचाई
चरण 2: दरवाजे (21 sqft प्रत्येक) और खिड़कियां (12 sqft प्रत्येक) घटाएं
चरण 3: इमल्शन पेंट कवरेज: 120–160 sqft प्रति लीटर (1 कोट)
चरण 4: 10% बर्बादी जोड़ें
उदाहरण: 15×12 ft का कमरा, 10 ft ऊंचाई, 2 दरवाजे, 3 खिड़कियां, 2 कोट, प्रीमियम इमल्शन:
दीवार क्षेत्र = 540 sqft → घटाएं 78 sqft → 462 sqft
पेंट = 462 ÷ 70 = 6.6 लीटर + 10% = ~7.3 लीटर
पेंट (लीटर) = पेंटेबल क्षेत्र (sqft) ÷ प्रति लीटर कवरेज × कोट की संख्या
चरण 1: दीवार क्षेत्र = 2 × (लंबाई + चौड़ाई) × ऊंचाई
चरण 2: दरवाजे (21 sqft प्रत्येक) और खिड़कियां (12 sqft प्रत्येक) घटाएं
चरण 3: इमल्शन पेंट कवरेज: 120–160 sqft प्रति लीटर (1 कोट)
चरण 4: 10% बर्बादी जोड़ें
उदाहरण: 15×12 ft का कमरा, 10 ft ऊंचाई, 2 दरवाजे, 3 खिड़कियां, 2 कोट, प्रीमियम इमल्शन:
दीवार क्षेत्र = 540 sqft → घटाएं 78 sqft → 462 sqft
पेंट = 462 ÷ 70 = 6.6 लीटर + 10% = ~7.3 लीटर
Construction Software
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