If you're flat-hunting in Mumbai, you'll hear three area figures thrown around almost interchangeably — carpet area, built-up area, and super built-up area (also called saleable area). They sound like technical variations of the same thing. They are not. Understanding the difference isn't optional homework; it directly affects the price per square foot you're actually paying, and by law, it's the one number your builder is required to disclose accurately.
The three terms, in plain language
1. Carpet Area
This is the actual usable floor area inside your flat — the space you could, in theory, cover with carpet. It's measured wall-to-wall, inside the four walls of your unit, and excludes the thickness of the walls themselves.
This is the number that matters most to you as a resident, and since RERA (Real Estate Regulatory Authority) came into effect, it's also the legally mandated figure builders must quote in agreements — precisely because it's the hardest number to inflate or obscure.
2. Built-Up Area
Carpet area, plus the thickness of your flat's internal and external walls, plus any balcony or terrace attached to the unit. Typically 10-15% larger than carpet area.
3. Super Built-Up Area (Saleable Area)
Built-up area, plus a proportional share of the building's common areas — lobbies, staircases, lifts, corridors, sometimes even the clubhouse or garden. This is almost always the largest number, and — not coincidentally — it's often the one used in marketing brochures and initial verbal quotes, because a bigger number sounds more impressive per rupee.
| Term | What it includes | Typical vs. Carpet Area |
|---|---|---|
| Carpet Area | Usable space inside your walls | Baseline (100%) |
| Built-Up Area | Carpet + wall thickness + balcony | ~110-115% |
| Super Built-Up Area | Built-up + share of common areas | ~125-145% |
If a flat is quoted at ₹1.2 crore for 950 sq ft "super built-up," and the actual carpet area is 680 sq ft, your real price isn't ₹12,631/sq ft — it's ₹17,647/sq ft on the space you actually live in. The same flat can look 25-30% cheaper per square foot than it really is, purely by which area figure gets quoted to you first.
How to verify the real numbers before you commit
- Ask for the RERA registration number and look up the project on your state's RERA portal (for Maharashtra: maharera.mahaonline.gov.in). The carpet area registered there is the legally binding figure — cross-check it against what you've been quoted verbally or in a brochure.
- Ask specifically for "carpet area," not "area." If a broker or builder gives you a number without specifying which type, ask directly — "Is this carpet area or super built-up?" Most won't lie if asked plainly; they'll just default to the more flattering number if you don't ask.
- Request the sanctioned floor plan. A proper architectural floor plan will have dimensions marked for each room — you can calculate carpet area yourself from these, room by room.
- Do a rough on-site check. Measure a couple of rooms with a tape or laser measure and compare against the floor plan. Large discrepancies are a red flag worth raising before you go further.
For older resale properties (pre-RERA, before 2017), builders weren't required to disclose carpet area — many will only have "built-up" figures on record. In these cases, a floor-plan-based calculation or physical measurement is your most reliable option, since there's no RERA registration to cross-check against.
Why this is one of the first things we check
At NestVett, verifying the quoted carpet area against RERA records or the floor plan you share is a standard part of every evaluation — because it's one of the most common (and expensive) gaps between what buyers are told and what they're actually getting. It takes minutes to check properly, but it's easy to miss when you're juggling site visits, loan paperwork, and family opinions all at once.
Get an independent check before you sign
NestVett verifies carpet area, layout, Vastu, and lifestyle fit — before you commit to a purchase you can't undo.
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