Free tool
Carpet Area Calculator
Convert between carpet, built-up and super built-up area, see how much of what you pay for you can actually use, and compare flat prices on a like-for-like carpet-area basis.
How to use
How to use the carpet area calculator
- Choose which area you know — the brochure usually quotes super built-up; the RERA registration and agreement for sale quote carpet area.
- Enter the area in sq ft.
- Adjust walls and loading if the builder has told you the figures; otherwise keep the typical defaults.
- Add the quoted rate to see the true price per sq ft of carpet area — the fairest way to compare two projects.
- Optionally measure the flat room by room to check the carpet area you were given.
The maths
How it’s calculated
Built-up = carpet × (1 + walls & balconies %) [typically 10–20%]
Super built-up = carpet × (1 + loading %) [typically 25–40%]
Usable share = carpet ÷ super built-up
Price per carpet sq ft = total price ÷ carpet area
Loading is quoted on carpet area — the same convention Jainify uses for all estimates — and it includes your walls and balconies as well as the common areas.
What RERA says carpet area is
“carpet area” means the net usable floor area of an apartment, excluding the area covered by the external walls, areas under services shafts, exclusive balcony or verandah area and exclusive open terrace area, but includes the area covered by the internal partition walls of the apartment.— Section 2(k), Real Estate (Regulation and Development) Act, 2016 (India Code)
So internal walls count, but external walls, shafts, and your own balconies and terraces do not — they are shown separately. Projects in Chhattisgarh are registered with CG RERA and in Madhya Pradesh with MP RERA, where each project’s declared carpet areas can be checked.
Worked example
A 1,000 sq ft carpet-area 2BHK
- Built-up with 15% for walls and balconies: 1,000 × 1.15 = 1,150 sq ft.
- Super built-up with 30% loading on carpet: 1,000 × 1.3 = 1,300 sq ft.
- At ₹4,500 per sq ft of super built-up, the flat costs ₹58.5 lakh — that is ₹5,850 per sq ft of carpet area.
- Only 76.9% of the area you pay for is usable inside the flat.
Typical ratios
| Building type | Built-up over carpet | Loading on carpet | Carpet as % of super built-up |
|---|---|---|---|
| Independent house / row house | 10–20% | none (no common areas) | — |
| Low-rise apartment (no lift) | 10–20% | ≈ 25% | ≈ 80% |
| Apartment with lifts | 10–20% | ≈ 33% | ≈ 75% |
| High-rise with clubhouse & amenities | 10–20% | up to 40% | ≈ 71% |
Indicative ranges; every project differs. Ask the builder for the carpet area as registered with RERA.
Keep planning
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Open tool →FAQ
Carpet Area Calculator: common questions
What is the difference between carpet, built-up and super built-up area?
How do I convert super built-up area to carpet area?
Is balcony included in carpet area under RERA?
What is a reasonable loading percentage?
Where can I check a project’s carpet area?
Bought a flat? Plan the interiors around the carpet area.
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