2 November 2026

Carpet Area vs Built-Up Area vs Super Built-Up Area: What You Actually Pay For

When you look at a flat, its size can be given in three different ways: carpet area, built-up area, and super built-up area. They are not the same number. In India's top seven cities, the super built-up area was on average 40% bigger than the carpet area in early 2025, according to ANAROCK. This guide shows what each one means and which one you should compare before you buy.

What Is a Carpet Area?

The carpet area is the floor space inside your flat that you can actually live in: the bedrooms, living room, kitchen, bathrooms, and passages. It's the most accurate measure of a flat's size and the only one defined by RERA. The RERA Act (Section 2(k)) calls it the "net usable floor area" of an apartment. What counts:

Every usable net floor space inside the rooms of the flat (living room, bedrooms, kitchen, bathrooms, and passages).

What does not count:

The thickness of both internal partition walls and external walls.
Service shafts for pipes and ducts.
Your exclusive balcony or verandah.
Your exclusive open terrace.

Balconies are kept out: under RERA, the balcony is separate from the carpet area. This was not always the case: Maharashtra's older flat-ownership law counted balconies as part of the carpet area, so figures from pre-RERA paperwork may not match today's.

What Is a Built-Up Area?

The built-up area is the full patch of floor that your flat takes up. It starts with the carpet area and then adds the things the carpet area leaves out: the thickness of the walls, inside and outside, and the balcony or terrace that belongs only to your flat. Some builders also add service shafts. In short: built-up area = carpet area + walls + your balcony (and sometimes shafts). A good way to picture it: if someone drew a line around your flat on the floor plan and measured everything inside that line, that would be the built-up area. One honest warning. RERA does not use built-up area as the basis for selling a flat, and its exact meaning changes from one builder and one city to another.

What Is a Super Built-Up Area?

A super built-up area is a built-up area plus your share of everything the whole building shares. You will also hear it called the saleable area or simply the super area. The shared spaces usually include:

Lobbies, corridors, and staircases
Lifts and lift lobbies
Amenities such as the clubhouse, gym, pool, and garden

Every flat in the building is given a proportionate slice of these spaces, and that slice is added to the flat's built-up area. In short: super built-up area = built-up area + your share of the common areas. That is why it is the biggest of the three numbers. Where does it stand legally? The RERA Act defines only carpet area. It does not define a super area at all. In January 2024, UP RERA told builders to sell flats on carpet area only, and its chairman pointed out that the Act has no meaning for super area. But the super built-up area is still mentioned in brochures.

Loading Factor Explained:

The loading factor is the bridge between the carpet area and the super built-up area.

Turn it around and you can work out the super built-up area from the carpet area:

A quick example. A flat has a carpet area of 700 sq. ft. and a super built-up area of 910 sq. ft. The gap is 210 sq. ft., and 210 ÷ 700 = 0.30, so the loading is 30%. What share of your money buys usable space? Divide carpet by super built-up. For the flat above that is 700 ÷ 910, about 77%. Some people call this the efficiency of the flat. The higher it is, the more of the area you pay for is the area you can use. Remember what loading contains. The gap is not only common-area space. It also includes the thickness of your walls and your balcony, because those sit between carpet and super built-up too.