Carpet Area vs Super Built-Up Area: Why 82% Efficiency Changes What You Actually Pay

The verdict: Carpet area is the floor you can walk on. Super built-up area adds your share of lobbies, lifts, staircases and the clubhouse. Two homes quoted at the same ₹ per sq. ft. can differ by 400-plus usable square feet once efficiency is accounted for — a real price gap of around 17%. Always compare cost per carpet square foot. Never per super built-up.

Most buyers compare projects on the rate the sales executive quotes. That rate is almost always calculated on super built-up area, which is the largest of the three numbers and the one you have the least use for.

Here is the arithmetic that changes the decision.

Quick facts

That last pair is the whole problem. The law requires disclosure in carpet area. The sales conversation happens in super built-up area. Both can be true at once, and the gap between them is where money quietly disappears.

What RERA actually says

Section 2(k) of the Real Estate (Regulation and Development) Act, 2016 defines carpet area as the net usable floor area of an apartment. It excludes the area covered by external walls, areas under service shafts, exclusive balcony or verandah area, and exclusive open terrace area. It includes the area covered by internal partition walls.

Two things follow that buyers routinely miss.

Your balcony is not carpet area. It is excluded by the definition, even though it is exclusively yours. A generous balcony inflates your built-up and super built-up numbers without adding a single square foot of carpet.

Your private terrace is not carpet area either. For villaments and duplex units, exclusive open terrace area is expressly excluded. If a project markets a 3,944 sq. ft. unit with a large terrace, the carpet figure will land well below what the terrace-inclusive number suggests.

Since 2017, developers must disclose carpet area in the agreement for sale and on the RERA portal. The number exists. You have to ask for it.

The arithmetic that changes everything

Two homes. Identical quoted rate. Identical super built-up area. Very different purchases.

Illustrative figures, not any specific project's pricing.

Same money. Same headline rate. Project B delivers 360 more square feet you can actually put furniture in — roughly a full additional bedroom.

Read it the other way and it lands harder. To match Project B's usable space, Project A would need to sell you 3,514 sq. ft. of super built-up area. At ₹11,000, that is ₹3.87 crore — ₹57 lakh more for the same home.

A twelve-point efficiency gap is worth more than any discount you will negotiate. Most buyers spend weeks arguing over ₹200 per square foot and never ask about a variable worth ten times that.

Where the missing space goes

Loading is not a scam. It is your share of things that genuinely exist — the lobby you walk through, the lift you take, the fire staircase, the clubhouse, the corridors.

What varies is how much of that there is per home, and that is driven by building form.

High-rises load heavily. More lift shafts, longer corridors, larger structural cores, pressurised stairwells, refuge floors. Serving twenty floors costs area on every floor.

Low-rise buildings load lightly. Four floors need one small lift core and short corridors. Assetz Codename Paradise states 82% carpet efficiency for exactly this reason — 12 blocks of low-rise construction with four homes per cluster, rather than towers. Specifications are indicative and subject to change; the project is in pre-launch with RERA registration applied and not yet received, and under Section 3 of RERA a project cannot be advertised, marketed or sold before registration.

Amenity-heavy projects load heavily. A 60,000 sq. ft. clubhouse gets divided among the units. That is not automatically bad — you may want the clubhouse — but you are buying it by the square foot whether you use it or not. Worth asking yourself honestly how often you will use the amphitheatre.

There is no legal cap on loading in Karnataka. A 25% loading and a 45% loading are both permitted. Only disclosure is mandatory.

What to ask the sales team

Ask these in this order. Write the answers down.

A sales executive who cannot answer questions 1 and 2 immediately is either untrained or evasive. Both are useful signals.

Then verify independently. The carpet area is disclosed on the Karnataka RERA portal for every registered project. If the portal figure and the sales figure disagree, the portal is the one that binds. Our pre-site-visit checklist covers what else to confirm before you commit.

Calculating it yourself

Three steps, no spreadsheet required.

Step one — get the all-inclusive price. Base price plus floor rise, preferential location charges, parking, club membership and corpus fund. Exclude stamp duty, registration and GST for now, since those apply to both options equally.

Step two — divide by carpet area. Not super built-up. Not built-up. Carpet, as defined under Section 2(k).

Step three — compare that number across shortlisted projects.

Run it on every project in your shortlist and the ranking will frequently change. The project that looked cheapest per square foot is often not the cheapest per square foot you can stand on.

One caveat worth stating: efficiency is not the only variable. A high-loading project with a genuinely excellent clubhouse you will use every week may be worth it. The point is not that high loading is always wrong — it is that you should know the number before you decide, rather than discovering it after possession.