Paint Calculator
Estimate exactly how much paint your walls, room, or entire house needs. Enter your area, number of coats, and paint type — and get litres required plus an approximate cost, so you buy the right quantity the first time.
This calculator is useful in several situations, including Painting a single room or full house, Estimating paint cost before hiring a painter, Comparing distemper vs emulsion vs exterior paint budgets, Planning primer + paint quantity for new construction, and Checking a painter's quoted material quantity against a reasonable estimate. In each case, it applies the correct formula automatically so you get a precise result without manual calculation. For related figures, you can also check our cement-calculator, tile-calculator, brick-calculator, concrete-calculator, house-construction-cost-calculator, or rebar-cutting-length-calculator.
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How the Paint Calculator Works
Follow these simple steps to get accurate results instantly.
Enter Wall Area
Enter the total area you plan to paint in square feet — either measure it directly, or provide room length, width, and height and let the calculator work out the wall area for you, including a standard deduction for doors and windows.
Select Number of Coats
Choose 1, 2, or 3 coats. Most interior walls need 2 coats for even, opaque coverage — new or bare walls, or a major colour change (e.g. dark to light), often need a 3rd coat or a coat of primer first.
Choose Paint Type
Select distemper, emulsion, enamel, or exterior weatherproof paint. Each type has a different coverage rate per litre, which directly changes how much paint you'll need for the same wall area.
View Paint Required & Cost
See the total litres needed, how many cans to buy (in standard 1L, 4L, 10L, and 20L sizes), and an estimated total cost based on average market rates for your chosen paint type.
Paint Quantity Formula
Paint Required (Litres) = (Paintable Area in sq ft ÷ Coverage per Litre) × Number of Coats
The core calculation starts with your paintable area, not your total wall area — this is an important distinction most people miss. Paintable area is your total wall area minus the space taken up by doors, windows, and any built-in fixtures, since you don't paint over those. A standard deduction of roughly 10-15% of total wall area is typically applied for a room with average-sized doors and windows, though this can vary if you have unusually large windows, sliding doors, or a feature wall with built-in wardrobes. Once you have the paintable area, coverage per litre depends entirely on the paint type you choose. Distemper, the most economical option, typically covers around 120-140 sq ft per litre. Premium emulsion paints generally cover 100-120 sq ft per litre — slightly less than distemper because emulsions are thicker and designed for a smoother, more durable finish. Enamel paint, used mostly for doors, windows, grills, and metal surfaces rather than full walls, covers considerably less per litre, typically 120-150 sq ft but applied in much thinner, more careful coats. Exterior weatherproof paints usually cover 100-110 sq ft per litre, since they're formulated to be thicker and more durable against sun and rain exposure, which reduces their spread rate compared to interior paints. The number of coats then multiplies directly against this base quantity. Two coats is the standard recommendation for almost all wall painting, since a single coat rarely gives even, opaque colour — you can usually see patches of the original wall colour or primer showing through. A third coat is typically needed only when painting a significantly darker colour over a lighter one (or vice versa), when the existing wall surface is uneven or heavily stained, or when using a lower-quality paint with weaker pigment concentration. It's also worth budgeting a small wastage allowance — typically 5-10% — on top of the calculated quantity, to account for paint lost during mixing, brush/roller loading, and touch-ups, since running short mid-job and needing to colour-match a second batch is a common and avoidable frustration.
Example Calculation
Input: Room: 12 ft × 10 ft, Height: 10 ft, Paint Type: Emulsion, Coats: 2
Output: Total wall area = (2 × (12+10) × 10) = 440 sq ft. After ~12% deduction for doors/windows → Paintable area ≈ 387 sq ft. At 110 sq ft/litre coverage: 387 ÷ 110 = 3.5 litres per coat × 2 coats = 7 litres total → round up to one 10L can, or a 4L + 4L combination.
Common Uses
- • Painting a single room or full house
- • Estimating paint cost before hiring a painter
- • Comparing distemper vs emulsion vs exterior paint budgets
- • Planning primer + paint quantity for new construction
- • Checking a painter's quoted material quantity against a reasonable estimate
Frequently Asked Questions
Find answers to common questions about this calculator.
What Is a Paint Calculator?
A Paint Calculator helps you work out exactly how much paint to buy before you start a painting project — whether that's a single room, a full house interior, or an exterior repaint. It takes your wall area (or room dimensions), your chosen paint type, and the number of coats you plan to apply, and converts these into a litre quantity and an estimated cost. This matters more than it might seem: buying too little paint means a mid-project trip back to the store and the risk of a slightly different batch not matching your original colour exactly, while buying too much means unnecessary expense and leftover paint that often goes to waste once it's opened.
Like any estimation tool, this calculator gives you a well-informed planning figure, not an exact-to-the-millilitre guarantee. Actual paint consumption depends on your specific wall texture, painting technique, brush versus roller application, and how porous or previously-painted your surface is — all of which shift real-world coverage somewhat from a manufacturer's stated rate. Use the result as your starting shopping list, and keep the wastage buffer in mind rather than buying the exact calculated litres with nothing extra.
Why Getting Paint Quantity Right Matters
Painting is one of the few home improvement costs where both under-buying and over-buying carry real downsides. Running short mid-project is disruptive — you have to pause, buy more, and hope the new can matches your existing paint closely enough that the join isn't visible, which becomes a genuine risk with custom-tinted colours where even the same "shade name" can vary slightly between batches. Over-buying, on the other hand, ties up money in paint that often can't be returned once opened, and paint that sits unused for a long period can separate, thicken, or degrade before you get around to using it for touch-ups.
Getting the estimate right also helps when you're hiring a painter, since it gives you a reasonable independent benchmark to compare against their quoted material quantity — a useful check against both accidental overestimation (padding the material cost) and underestimation (a quote that looks attractively low because it's based on too little paint, with the shortfall becoming your problem, or an unexpected added cost, partway through the job).
Average Paint Cost Per Sq Ft in India
| Paint Type | Material Cost (per sq ft, 2 coats) | Typical Use |
|---|---|---|
| Distemper | ₹8–14 | Budget interiors, rental properties |
| Standard Emulsion | ₹15–25 | Most interior walls |
| Premium/Luxury Emulsion | ₹25–45 | Living rooms, feature walls, higher-end finish |
| Exterior Weatherproof | ₹20–35 | External walls, weather exposure |
| Enamel | ₹30–50 | Doors, windows, grills, metal surfaces |
These figures cover material cost only. Add labour separately — typically ₹12-20 per sq ft depending on your city and the painter's experience — to arrive at a full, all-in painting cost.
Paint Coverage by Type (Per Litre, Per Coat)
| Paint Type | Coverage per Litre |
|---|---|
| Distemper | 120–140 sq ft |
| Standard Emulsion | 100–120 sq ft |
| Exterior Weatherproof | 100–110 sq ft |
| Enamel | 120–150 sq ft (thin coats) |
These are manufacturer-typical ranges for a reasonably smooth, prepared surface. Rough, textured, or unprimed porous walls will absorb more paint and reduce actual coverage — build in extra buffer if your walls fall into that category.
Estimated Paint Quantity by House Size
| House Size (Built-up Area) | Approx. Paintable Wall Area | Emulsion Needed (2 Coats) |
|---|---|---|
| 1 BHK (~500 sq ft) | 1,200–1,400 sq ft | 22–28 litres |
| 2 BHK (~800 sq ft) | 1,900–2,200 sq ft | 35–42 litres |
| 3 BHK (~1,200 sq ft) | 2,800–3,300 sq ft | 52–62 litres |
| Independent house (1,500 sq ft, 2 floors) | 3,600–4,200 sq ft | 66–78 litres |
These figures cover interior walls only, using standard emulsion at 2 coats. Ceilings, exterior walls, and enamel work on doors/windows are separate additions to these totals.
How to Reduce Paint Wastage and Cost
- Measure carefully before buying: Use actual room dimensions rather than rough guesses — the deduction for doors and windows adds up meaningfully across a full house.
- Buy in bulk sizes where possible: A single 20L can is usually cheaper per litre than several smaller cans, and reduces the risk of slight colour variation between different batches.
- Use primer on new or bare walls: Primer is cheaper than finish paint and reduces how many coats of the more expensive paint you need for full opacity.
- Choose the right finish for the surface: Don't use premium emulsion on surfaces that see little wear, or basic distemper on high-touch areas that will need repainting sooner as a result.
- Get a small sample first: For a custom or unfamiliar colour, a small sample tester can confirm the shade looks right under your room's actual lighting before you commit to buying the full quantity.
Common Mistakes When Estimating Paint
The most frequent mistake is calculating paint based on floor area instead of wall area — these are very different numbers, and using floor area will significantly under- or over-estimate your actual requirement depending on ceiling height. A second common mistake is forgetting to deduct for doors and windows, which can overstate paint needed by 10-15% for a typical room. Skipping the wastage buffer is another frequent gap, since real-world application always uses somewhat more paint than the theoretical coverage rate suggests, especially on textured surfaces or with less experienced painters. Finally, mixing up single-coat and two-coat coverage is an easy error — always confirm whether the coverage rate you're using from a paint can label is per coat, and multiply by your intended number of coats accordingly, since the number on the can typically reflects a single-coat application only.
Who Should Use This Calculator?
- Homeowners planning to paint a room, full house interior, or exterior.
- Anyone comparing a painter's quoted material quantity against a reasonable independent estimate.
- People deciding between distemper, emulsion, and premium finishes based on budget.
- New homeowners planning primer and finish paint quantities for freshly constructed walls.
- DIY painters wanting to buy the right amount of paint the first time, without a mid-project store run.
Limitations of This Calculator
This calculator provides a planning-stage estimate based on typical coverage rates for standard paint types on a reasonably smooth, prepared surface. It cannot account for unusually rough or heavily textured walls, the specific brand and product line you choose (coverage varies somewhat between manufacturers), your painting technique, or site-specific conditions like humidity, which can affect drying time and, indirectly, how evenly paint settles. Use the result as a starting shopping list, add a wastage buffer, and confirm exact quantities against the specific paint brand's coverage guidance printed on the can before making your final purchase.