Carpet, Built Up and Super Built Up Area Calculator
Builders quote super built up area. You live on carpet area. Enter whichever number you have and see the other two, plus the rate you are really paying.
Want the exact figure? Send us what you have worked out and we will tell you exactly what an official valuation report involves.
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Three numbers for one flat
Carpet area is the space inside your flat that you could actually lay a carpet on. Under RERA it is defined as the net usable floor area within the walls, excluding the external walls, the shaft area and the balcony, but including the internal partition walls.
Built up area is the carpet area plus the walls themselves, plus the balcony. It usually runs about 10 to 15 percent above carpet.
Super built up area adds your share of everything the building has in common. The lobby, the staircase, the lift shafts, the club house, the corridors, sometimes the swimming pool. That addition is called loading, and it is where the money hides.
Loading is not regulated
This is the part buyers miss. There is no cap on loading. One builder charges you for a 20 percent share of common areas and another charges 40 percent, and both are legal.
Two flats advertised as 1,200 square feet at the same rate can therefore differ by nearly 200 square feet of actual living space. The cheaper looking flat is often the worse deal.
Whenever you compare two projects, convert both to carpet area first and compute the rate on that. It is the only comparison that means anything.
What RERA changed and what it did not
Since RERA, a developer must quote and sell on carpet area, and the definition is fixed by statute rather than by the marketing department. That was a genuine improvement.
What did not change is conversation. Brokers still quote super built up, resale listings still quote super built up, and older societies were built and sold entirely on it. So you will keep meeting the number, and you will keep needing to translate it.
Which area a valuer uses
For a valuation we measure the property ourselves and work from the actual measured area, cross checked against the sanctioned plan and the sale deed.
That matters because the deed area, the builder brochure area and the measured area are not always the same. Where they differ, the report says so and explains which was used, which is exactly what a bank or a court needs to see.
It also matters for loans. A bank lends against a valuation built on real measurement, not on a brochure, which is one of the reasons a bank valuation can land lower than an owner expects. That gap is explained here.
Questions people ask us
- What exactly counts as carpet area under RERA?
The net usable floor area inside the flat, excluding the external walls, the service shafts, the exclusive balcony or verandah and the exclusive open terrace, but including the internal partition walls.
- Is there a legal limit on loading?
No. Loading is not capped, so two projects on the same road can load 20 percent and 40 percent. This is why comparing rates per square foot of carpet area, rather than the quoted rate, is the only fair comparison.
- Which area is written in my sale deed?
It varies. Newer agreements under RERA state carpet area. Older deeds often state built up or super built up, and some state a plot share instead. A valuer measures the property and states what was actually found.
- Why is the bank valuation lower than the builder area?
Because a bank values on measured reality and lends conservatively, while a brochure sells on the largest defensible number. The two are answering different questions.
Checked by Parish Rao, Chartered Engineer and Government Approved Valuer.
Page last checked on 27 August 2026.