Calculate exactly how much paint, primer, and putty you need for your walls. Enter your total wall area below for an instant estimate.
🎨 Paint Calculator
Wall paint — paint, primer & putty quantity
📋 Calculation Details
Coverage: ~120 sq ft per litre per coat. Includes 10% wastage.
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Frequently Asked Questions
How much paint do I need for 1000 sq ft?
For 1000 sq ft with 2 coats at 120 sq ft/litre coverage and 10% wastage: 18.3 litres (4.8 US gallons).
What is the coverage of 1 litre of paint?
Approximately 120 sq ft per litre per coat for emulsion paint on smooth plastered walls.
Do I need primer before painting?
Yes, primer improves adhesion and reduces paint consumption, especially on new plaster. Apply 1 coat of primer before 2 coats of paint.
How much putty is required?
Approximately 1 kg per 30 sq ft for wall putty (2 coats). For 1000 sq ft, you need about 33 kg.
What is the difference between sq ft and sq m input?
Select “Imperial” for square feet or “Metric” for square meters. The calculator converts automatically (1 sq m = 10.76 sq ft).
How to Use This Paint Calculator
- Enter the total wall area in square feet (or square metres — switch the unit toggle). Measure every wall: length × height, then subtract doors and windows.
- Set the number of coats — 2 coats is standard for emulsion over primer.
- Include primer? Tick yes for new plaster or repainting over a dark colour.
- Set wastage % — 10% is the site standard (spills, brush loss, touch-ups).
- Read your results: paint required (litres and US gallons), primer (litres), and putty (kg).
Practical note: The calculator uses 120 sq ft per litre per coat — the real-world coverage of plastic emulsion on smooth plastered walls in Pakistan. Rough or unplastered surfaces drink far more paint; bump wastage to 15–20% for them.
Paint Calculation Formulas
Paint (litres) = (Wall area ÷ Coverage per litre) × Coats × (1 + Wastage%)
Primer (litres) = (Wall area ÷ Primer coverage) × 1 coat × (1 + Wastage%)
Putty (kg) = Wall area ÷ 30 (approx. 1 kg per 30 sq ft for 2 coats)
Paint Coverage Rates (Pakistan Market)
Coverage varies by paint type and surface. Use this table to sanity-check the calculator:
| Paint type | Coverage (sq ft/litre/coat) | Typical use |
|---|---|---|
| Plastic emulsion | 110–130 | Interior walls (standard) |
| Weather-shield / exterior emulsion | 90–110 | Exterior walls |
| Oil-bound distemper | 100–120 | Budget interior |
| Enamel (oil paint) | 130–150 | Doors, windows, grills |
| Primer (wall primer) | 100–120 | Base coat on new plaster |
| Texture paint | 40–60 | Feature walls |
On rough plaster or previously unpainted brick, expect 20–30% lower coverage — I have seen contractors caught short by exactly this.
Worked Example — 1,000 Sq Ft House
Interior walls, 2 coats of plastic emulsion, primer included, 10% wastage:
- Paint = (1000 ÷ 120) × 2 × 1.10 = 18.3 litres (4.8 US gallons)
- Primer = (1000 ÷ 110) × 1 × 1.10 = 10 litres
- Putty = 1000 ÷ 30 = 33 kg
So for a 1,000 sq ft paint job: buy one 16-litre drum + one 4-litre gallon of emulsion, one 10-litre primer, and two 20-kg putty bags. Round up to the nearest pack size — paint shops don’t sell 18.3 litres.
How to Measure Wall Area Correctly
The #1 mistake: guessing. Do it properly — it takes 10 minutes:
- Measure each wall’s length × height.
- Add all walls together.
- Subtract openings: standard door ≈ 21 sq ft (3×7 ft), standard window ≈ 12–15 sq ft.
- For ceilings, add length × width separately (ceilings usually get white emulsion, 1–2 coats).
Rule of thumb check: a 10×12 ft room with 10-ft ceilings has roughly 440 sq ft of wall minus ~35 sq ft of door/window = ~400 sq ft paintable.
Estimating Paint Cost (Pakistan, 2026)
Material cost per sq ft helps you quote or check a contractor’s bill:
| Item | Approx. rate | For 1,000 sq ft |
|---|---|---|
| Plastic emulsion (good brand) | Rs. 900–1,200 / litre | ~Rs. 18,000–22,000 |
| Wall primer | Rs. 400–600 / litre | ~Rs. 4,000–6,000 |
| Wall putty | Rs. 1,200–1,800 / 20-kg bag | ~Rs. 2,400–3,600 |
| Labour (2 coats + putty) | Rs. 25–45 / sq ft | ~Rs. 25,000–45,000 |
Rates vary by city and brand — treat as budgeting guides, not quotations. Labour is usually the biggest line item, which is why accurate material estimates matter: they stop contractors from padding the paint bill.
Field Tips from Site
- Always prime new plaster. Skipping primer on fresh plaster doubles paint consumption — the plaster drinks the first coat. Primer is cheaper than paint.
- Two thin coats beat one thick coat every time: better finish, better hiding, no drips.
- Buy 5–10% extra of the exact shade and keep the shade card. Touch-ups a year later never match a different batch.
- Putty before paint, always. Two coats of wall putty + sanding gives the smooth finish emulsion needs. 1 kg covers ~30 sq ft.
- Exterior paint ≠ interior paint. Weather-shield costs more but survives sun and rain; interior emulsion chalks and fades outdoors within a year.
- Paint in shade, not direct sun. Hot walls dry the paint too fast, leaving lap marks and poor adhesion. Start early morning on east walls, finish west walls before afternoon sun hits them.
Frequently Asked Questions
How much paint do I need for 1000 sq ft?
For 1000 sq ft with 2 coats at 120 sq ft/litre coverage and 10% wastage: 18.3 litres (4.8 US gallons). Add 10 litres of primer and ~33 kg of putty.
What is the coverage of 1 litre of paint?
Approximately 120 sq ft per litre per coat for plastic emulsion on smooth plastered walls. Exterior and texture paints cover less.
Do I need primer before painting?
Yes — one coat of primer on new plaster improves adhesion, seals the surface, and reduces paint consumption. On previously painted walls in good condition, you can sometimes skip it.
How much putty is required?
About 1 kg per 30 sq ft for two coats of wall putty. For 1000 sq ft, budget ~33 kg (two 20-kg bags).
How many coats of paint should I apply?
Two coats over one coat of primer is the standard for a durable finish. One coat looks patchy; three coats is rarely needed except for drastic colour changes.
How do I calculate paint for a room?
Measure wall area (length × height per wall, minus doors/windows), then use the formula: litres = (area ÷ 120) × coats × 1.10. Or just use this paint calculator above.
Does dark paint need more coats?
Going from dark to light needs 3 coats (or a tinted primer first). Going light to dark usually covers in 2. Always prime when changing colour families.
What is the difference between sq ft and sq m input?
Select “Imperial” for square feet or “Metric” for square metres. The calculator converts automatically (1 sq m = 10.76 sq ft).
Final Thoughts
A paint calculator takes the guesswork out of material purchase — measure honestly, use real coverage rates, and always budget the primer and putty, not just the paint. The cheapest paint job is the one you buy correctly the first time.
Written by Mohsin Raza Adil — BSc Civil Engineering Technologist (NTC-registered), Pakistan.