Carpet Area vs Super Built-Up Area: What You Actually Buy

A Bengaluru buyer compared two flats priced almost the same per square foot and picked the one that looked larger on paper at 1,300 square feet. When he moved in, the home felt smaller than a neighbour's 1,150 square foot flat. The reason was not his imagination. His 1,300 was super built-up area, carrying a heavy loading of shared space, while the neighbour's number was closer to carpet area. He had compared the wrong measurement, and paid for corridors and lobbies he could not live in. Knowing which area you are buying changes everything.

The short answer. Carpet area is the net usable space within your apartment walls, the space you actually live in. Built-up area adds the walls and is roughly 110 to 115 percent of carpet, while super built-up area adds a share of common areas like lobbies and corridors and runs about 125 to 140 percent of carpet. The gap is called the loading factor. Under RERA, builders must price and declare a home on carpet area in the sale agreement, and if the delivered carpet area falls short of what was promised, you are entitled to a refund with interest. The trade-off to understand: a tempting price per square foot quoted on super built-up area can hide a high loading, so always compare flats on carpet area, because that is the space you occupy and finance.

What is carpet area, and why does RERA use it?

Carpet area is the actual usable floor area within the walls of your apartment, literally the space where you could lay a carpet. Under the RERA definition it is the net usable area within the walls, excluding the external walls, service shafts, and any exclusive balcony or open terrace, while including the internal partition walls. In plain terms, it is the room you live in, sleep in and cook in, the space that is genuinely yours to use.

RERA uses carpet area because it is the honest, comparable measure of what a buyer gets. Before RERA, developers routinely sold on inflated super built-up figures, so two flats with the same quoted size could have very different real space. As property guides on carpet versus built-up area explain, standardising on carpet area protects buyers by fixing what you actually own and use, rather than a number padded with shared space.

The practical value of this shows up the moment you compare homes. When every project must state carpet area, you can line up two flats and see, honestly, which gives you more room to live in for your money. Before this rule, a larger sounding flat could deliver less usable space than a smaller sounding one, and buyers had no easy way to tell. Carpet area turned a confusing, seller controlled number into a common yardstick, which is exactly why it deserves to be the figure you anchor every comparison and every price negotiation to.

How do carpet, built-up and super built-up differ?

The three measures stack outward from the space you use to the space you share. Carpet area is the usable space inside your walls and is the baseline. Built-up area adds the thickness of the walls and your balcony and utility areas, coming to roughly 110 to 115 percent of the carpet area. Super built-up area then adds your proportionate share of common areas such as the lobby, corridors, staircases and amenities, typically landing around 125 to 140 percent of the carpet area.

The table below shows the three side by side, so you can see how the same home can be described with three very different numbers depending on which area a seller chooses to quote.

What is the loading factor, and how does it inflate the number?

The loading factor is the percentage added to your carpet area to arrive at the super built-up area, representing your share of the common spaces. A 30 percent loading means a flat with 1,000 square feet of carpet is sold as 1,300 square feet of super built-up. The higher the loading, the more of your money goes toward space you cannot occupy, so a lower loading factor is genuinely better for the buyer.

This is where headline comparisons mislead. Two projects can quote a similar price per square foot on super built-up area, yet the one with the higher loading gives you less actual home for the same money. To compare fairly, convert both to a price per square foot of carpet area, or simply compare the carpet areas directly. The loading is not a scam in itself, since common areas are real and shared, but it must be visible to you, not hidden inside a flattering total.

What does RERA require builders to do?

RERA requires builders to sell on carpet area and to declare that carpet figure in the sale agreement and the registered project details. This means the number you legally sign for, and can hold the builder to, is the usable carpet area, not a marketing super built-up figure. It is a direct consumer protection, designed to stop the old practice of charging for inflated area.

There is a further protection if the delivered home falls short. If the actual carpet area is less than what was promised in your agreement, RERA entitles you to a refund of the excess amount you paid, with interest. Some guides cite a small tolerance and a set interest rate, but the exact figures can depend on your state's RERA rules, so confirm the specific tolerance and interest that apply to your project. Either way, the carpet area in your agreement is a promise the builder is bound to keep.

How does area affect your price, loan and value?

Area affects almost every number in your purchase. Your price is really a price per square foot multiplied by an area, so which area is used changes what you are effectively paying for usable space. Banks, notably, tend to base their loan and valuation on carpet area rather than super built-up, so a home padded with heavy loading may not support as large a loan as its headline size suggests.

Resale value follows the same logic over time. A flat with a lower loading and more usable carpet for its price tends to feel larger and hold value better than one where much of the quoted area is shared space. So carpet area is not just a technicality for the agreement, it is the number that quietly drives your cost per usable foot, your loan, and how the home compares to others when you eventually sell.

A quick calculation makes the point concrete. Suppose a flat quotes 1,300 square feet super built-up at a certain rate, with a 30 percent loading, so its carpet is about 1,000 square feet. A rival quotes 1,150 super built-up at the same rate but with only a 15 percent loading, giving a carpet of about 1,000 as well. On the brochure the first looks bigger and better value, but you are getting the same usable home for more money. Running that carpet based comparison, rather than trusting the headline size, is what separates a good buy from an expensive one.

How should a Bengaluru buyer check the area?

Check the area by asking for the carpet area in writing and matching it against the sale agreement and the RERA registered details, rather than accepting a super built-up number from a brochure. Ask the builder for the carpet area, the built-up area and the loading factor separately, so you can see exactly how the quoted size was built up. If a seller will only talk in super built-up terms, treat that as a prompt to dig for the carpet number.

Fold this into your wider checks so the number you finance matches the number you signed for. Confirm the carpet area alongside the terms in your builder buyer agreement, and remember that your stamp duty is charged on value, not the padded area. Whether you are comparing resale flats or a project such as Brigade Kadugodi in Whitefield, compare on carpet area, because that is the home you actually get.

Seven step area verification checklist

1. Ask for the carpet area of the flat in writing, not just the super built-up.
2. Ask separately for the built-up area and the loading factor.
3. Match the carpet area against the sale agreement wording.
4. Cross check it with the RERA registered project details.
5. Convert the price to a rate per square foot of carpet to compare fairly.
6. Prefer a lower loading factor for more usable space per rupee.
7. Confirm the delivered carpet area at possession against the agreement.

What is the difference between carpet area and super built-up area?

Carpet area is the usable space within your apartment walls. Super built-up area adds the walls, balcony and your proportionate share of common areas, and is usually about 125 to 140 percent of the carpet area. The gap between them is the loading factor, which is space you pay for but cannot occupy.

Does RERA require builders to sell on carpet area?

Yes. Under RERA, builders must price and declare a home on carpet area and state it in the sale agreement. This replaced selling on inflated super built-up area. If the delivered carpet area is less than promised, RERA entitles the buyer to a refund of the excess paid with interest.

What is a loading factor in real estate?

The loading factor is the percentage added to your carpet area to reach the super built-up area. A 30 percent loading means 1,000 square feet of carpet is sold as 1,300 square feet super built-up. A lower loading factor is better for the buyer, because more of what you pay for is usable.

Which area do banks use for a home loan?

Banks generally base their loan and valuation on carpet area rather than super built-up, since carpet reflects real usable space. This means a home with heavy loading may not support as large a loan as its headline super built-up size suggests. So confirm the carpet area early, so your loan matches your expectations.

Last updated 2026-09-07. PropNewz Team.