Paint Calculator: Wall Paint, Putty, Primer and Cost
A 3.6 × 3 × 3 m room with one door, one window and its ceiling needs about 4.06 L of interior emulsion for two coats (one 4 L and one 1 L can), including a 5% allowance. Enter your rooms or wall area to get paint litres, primer, wall putty and a painting budget.
Coverage from manufacturer data sheets and reported Indian cost bands, checked 20 October 2026.
Measure your walls and ceiling
Use internal clear dimensions for rooms. For exterior elevations, use direct wall area or external dimensions; ceilings here mean soffits. Run different colours or products separately.
Choose the coating scope
Repaint sets putty to 0%; enter a repair percentage if needed. Primer covers the full area. The 5% allowance is editable. Confirm the primer and putty sequence with your supplier.
Your paint estimate
46.71 m² · 502.78 sq ft
Walls 39.6 − openings 3.69 + ceiling 10.8 = 46.71 m²
Wall putty
32.7 kg
Buy: 1 × 40 kg = 40 kg
Spare after allowance: 7.3 kg
Primer
2.46 L
Buy: 3 × 1 L = 3 L
Spare after allowance: 0.54 L
Finish paint
4.06 L
Buy: 1 × 4 L + 1 × 1 L = 5 L
Spare after allowance: 0.94 L
Quantities include 5% allowance. Packs minimise purchase volume using 1/4/10/20 L and 20/40 kg; check availability by shade. Round each colour separately. Dilution water is not extra paint.
Approximate material + labour budget
₹6,033–₹10,056
Basic interior, putty + primer + emulsion: reported ₹12–20/sq ft × 502.78 sq ft.
Labour-only reference: ₹3,017–₹5,028 at ₹6–10/sq ft. Already included in the combined benchmark; do not add it again.
A reported benchmark, not a price for these brands. Extra coats change litres, not this band. Get a local quote for repairs, access and small-job minimums. Rate sources and exclusions.
Worked example: one 3.6 × 3.0 × 3.0 m room
The room has 46.71 m² to paint and needs 32.7 kg of putty, 2.46 L of primer and 4.06 L of finish paint. Inputs: new interior work, one 0.90 × 2.10 m door, one 1.20 × 1.50 m window and the ceiling. Two putty coats over the whole area, one primer coat, two finish coats and one colour. No reveals, beam drops or tiled areas.
| Step | Exact calculation | Result |
|---|---|---|
| Gross walls | 2 × (3.6 + 3.0) × 3.0 | 39.60 m² |
| Openings | (1 × 0.90 × 2.10) + (1 × 1.20 × 1.50) | 3.69 m² |
| Net walls | 39.60 − 3.69 | 35.91 m² |
| Ceiling | 3.6 × 3.0 | 10.80 m² |
| Total surface | 35.91 + 10.80 | 46.71 m² |
| Square feet | 46.71 ÷ 0.09290304 | 502.78 sq ft (rounded) |
| Putty, two coats + 5% | 46.71 ÷ 1.5 × 1.05 | 32.697 kg → 1 × 40 kg bag |
| Primer, one coat + 5% | (46.71 ÷ 0.09290304) ÷ 215 × 1.05 | 2.455 L → 3 × 1 L |
| Finish, two coats + 5% | (46.71 ÷ 0.09290304) ÷ 130 × 1.05 | 4.061 L → 1 × 4 L + 1 × 1 L |
At the reported basic-interior ₹12–20/sq ft band, the combined material-and-labour budget is ₹6,033–₹10,056, rounded from the unrounded surface area. Labour alone at ₹6–10/sq ft is ₹3,017–₹5,028; it is already inside that band, not an extra. A single small room may attract a minimum job charge.
Coverage assumptions and manufacturer data sheets
The calculator uses the lower end of each published coverage range, so it errs towards buying slightly more. These are reference products, not a recommendation. Check the current sheet for the product you buy. Sources checked 20 October 2026.
| Manufacturer source | Published coverage | Calculator assumption | Sheet date |
|---|---|---|---|
| Asian Paints Tractor Emulsion | 130–150 sq ft/L, two coats (250–270 for one coat) | 130 sq ft/L for two coats; 250 for one | 1 January 2014 |
| Asian Paints Apex Ultima | 55–65 sq ft/L, two coats | 55 sq ft/L for two coats | 14 November 2024 |
| Asian Paints Decoprime Advanced Cement Primer WT (0361) | 215–270 sq ft/L, one coat | 215 sq ft/L per coat | 16 October 2015 |
| Asian Paints Exterior Wall Primer (0065) | 120–140 sq ft/L, one coat | 120 sq ft/L per coat | 1 July 2012 |
| Birla White WallCare Putty technical brochure | 1.5–2.0 m²/kg, two coats on smooth normal mortar | 1.5 m²/kg for two coats | Undated; checked 20 October 2026 |
For two-coat coverage C, quantity = area ÷ C. For other coat counts the calculator scales by coats ÷ 2, except one coat of Tractor Emulsion, where the sheet’s own 250 sq ft/L is used. Three-coat paint and one- or three-coat putty are straight-line estimates, not manufacturer figures.
Putty use depends on thickness as well as coats, and the brochure figure is for smooth mortar; rough walls need a site trial. The 5% handling allowance is our editable assumption. Quantities are paint as bought; adding water when thinning does not reduce the litres you need.
Some systems call for primer both before and after putty. If yours does, set primer to two coats. Spot priming needs a separate area.
How to measure walls before buying paint
Buy paint for the net painted surface: wall faces less openings, plus the ceiling if it is painted.
- Measure each rectangular room’s clear length, breadth and painted height in metres. Wall area is 2 × (L + B) × H. For an irregular plan, add the individual wall lengths × heights in direct-area mode.
- Count doors and windows on each painted room face. Enter their opening width and height; the calculator subtracts count × width × height. For mixed opening sizes, calculate their combined area and enter net wall area with zero opening counts.
- Include the ceiling only when it is in the paint scope. Its area is L × B. For slopes, coffers or beam drops, measure the actual faces separately. Exclude tiled wall portions, cupboards and unpainted finishes.
- Use separate runs for exterior elevations, interior walls, ceilings in another colour and any different paint product. Exterior direct area should come from elevation lengths × heights, not interior room sizes.
- Measure and add painted reveals/returns separately. This tool deducts entire openings for consumption; contractual deductions and joinery coefficients belong in a painting BOQ measurement sheet.
How the painting budget is estimated
Budget = net painted surface in sq ft × reported supply-and-apply rate. The calculator reuses the bands in our painting rate per sq ft guide: basic new interiors ₹12–20, interior repaint without putty ₹8–16, premium weatherproof exterior ₹25–40, and labour alone ₹6–10. These are HouseYog’s reported ranges, updated 26 March 2026 and checked for our guide on 20 October 2026. Read the original rate report.
If an interior repaint includes any putty, the budget switches to the basic-interior band. Exterior uses the weatherproof band because the quantity reference is Apex Ultima, a premium exterior paint. Changing coats changes litres and kg, but not the rate band.
For an item-wise quote, the painting BOQ Excel example prices putty at ₹90/m², primer at ₹35/m² and wall emulsion at ₹110/m², each supply and application. It also separates preparation, ceilings, wood and metal.
Common mistakes that change the order quantity
Most wrong paint orders come from using floor area for walls or doubling a two-coat coverage figure.
- Using floor area as wall area, or charging two coats as twice the payable surface.
- Multiplying by two when the manufacturer already quotes two-coat coverage.
- Deducting doors twice after entering a net wall area, or forgetting window reveals.
- Rounding all colours into a single tin. Pack rounding applies separately to each shade and product.
- Treating full putty as compulsory on sound repaint work, or assuming extra putty solves dampness.
- Assuming the reported rate includes major repairs, stripping, waterproofing or scaffolding. Agree these separately.
Related: BOQ Excel templates · House construction cost calculator · All material calculators
Paint calculator FAQs
How do I calculate how much paint I need?
Measure the actual walls and ceilings, subtract unpainted openings, then divide by the coverage for your chosen product and coat system. Add a stated handling allowance and round each colour to available packs. A coverage stated for two coats already includes both coats.
How much paint is needed for a 3.6 × 3 × 3 m room?
About 4.06 L of interior emulsion for two coats, so buy one 4 L and one 1 L can of the same colour. With a 0.9 × 2.1 m door, a 1.2 × 1.5 m window and the ceiling, the painted area is 46.71 m² (502.78 sq ft). That is 502.78 ÷ 130 sq ft/L × 1.05 allowance. Primer and putty are extra.
How much wall putty is required per square metre?
About 0.5–0.67 kg/m² for two coats. The Birla White WallCare brochure gives 1.5–2.0 m²/kg for two coats on smooth normal mortar; this calculator uses 1.5 m²/kg (0.667 kg/m²) before allowance. Rough or uneven walls take more.
Does repainting need putty and primer?
Usually not full putty. Sound existing paint may need only local filling, so repaint mode starts at 0% putty; enter the percentage being repaired. Primer is still calculated over the full area. Check the primer to use with your supplier.
How many square feet does 1 litre of paint cover?
130–150 sq ft for two coats of a basic interior emulsion (Asian Paints Tractor Emulsion data sheet), and 55–65 sq ft for two coats of a premium exterior paint (Apex Ultima). Coverage varies by product. Rough or porous surfaces cover less.
Can I use my house floor area in the wall paint calculator?
No. Room walls are 2 × (length + breadth) × height; ceiling area is length × breadth. Carpet or built-up area is not wall area. Leave out tiled or unpainted walls. Use direct-area mode for irregular rooms and exterior elevations.
How are the 1, 4, 10 and 20 litre paint packs selected?
The calculator rounds up to the next whole litre, then picks the fewest cans that make that quantity. Putty rounds to 20 or 40 kg bags. It does not look for the cheapest combination; pack prices vary by product and shade.
What is the painting cost per square foot in India?
₹12–20 per sq ft of painted surface for basic interiors with material, as reported by HouseYog (March 2026). Repainting without putty is reported at ₹8–16, premium weatherproof exterior at ₹25–40 and labour alone at ₹6–10. The material bands already include labour, so do not add it twice.
Is the area suitable for a contractor's final bill?
No. This tool deducts full openings to estimate paint to buy and does not add reveals. A bill follows IS 1200 opening and reveal rules and separate coefficients for doors and grills. Use the painting BOQ workbook or measured drawings for billable quantities.
Painting a whole house? Get a BOQ from your drawings with painting measured room by room.