What Is the Difference Between Carpet Area, Built-up Area,and Super Built-up Area Under RERA?

By NyayKart Legal Team — Experts in RERA, Consumer Disputes & Property Law Across India

Buying a home is one of the most significant financial decisions in a person’s life, and yet many buyers remain confused about one fundamental question - what exactly are they paying for? Builders advertise large-sounding numbers such as “1,500 sq. ft. luxury flats,” but when possession happens, the actual usable area feels much smaller. This discrepancy arises because developers use different terms like carpet area, built-up area, and super built-up area to describe the property size. These variations, if not properly understood, can lead to inflated pricing and buyer frustration. To end this confusion and standardize the way property is measured and sold, the Real Estate (Regulation and Development) Act, 2016 (RERA) introduced a single legal benchmark - the carpet area.

Understanding the Key Terms Under RERA

The carpet area, as defined under Section 2(k) of RERA, refers to the net usable floor area of an apartment, excluding the area covered by external walls, service shafts, balconies, verandas, and open terraces, but including the space covered by internal partition walls. In simple terms, it is the actual usable area within the four walls of your apartment - the space where you can literally lay a carpet and move around. It includes the living room, bedrooms, kitchen, bathrooms, and internal walls but excludes external walls, balconies, and common spaces. This is the only measurement legally recognized under RERA for sale and registration. Builders are required to quote prices only on the basis of carpet area and cannot use any other measurement to misrepresent the property size.

Before RERA came into force, the term built-up area was commonly used by developers to calculate sale prices. Built-up area refers to the total space including the carpet area plus the area covered by internal and external walls, as well as balconies and terraces. It usually increases the total area by around 10–20 percent compared to the carpet area.

For example, a flat with a carpet area of 1,000 square feet would have a built-up area of approximately 1,200 square feet, depending on the thickness of walls and balcony size. Builders often quoted lower per-square-foot rates using built-up area to make prices seem attractive, but in reality, buyers paid a higher effective cost for the actual usable space.

An even more misleading term was super built-up area, also known as the “saleable area.” Super built-up area includes the built-up area plus a proportionate share of common areas such as lobbies, lifts, staircases, corridors, clubhouses, gardens, and other amenities. This term was widely misused to artificially inflate the total area and reduce the apparent rate per square foot. For instance, a builder could advertise a 1,500 sq. ft. flat at ₹4,000 per sq. ft., which seems affordable, but the actual carpet area might only be 1,000 sq. ft., meaning the buyer effectively pays ₹6,000 per sq. ft. for the usable space. This lack of standardization created confusion and allowed builders to obscure the real value of the property being sold.

RERA’s Legal Position and the Shift to Carpet Area

RERA was enacted to bring transparency and fairness to real estate transactions. One of its core reforms was the mandatory use of carpet area as the only valid basis for sale. Under Section 4(2)(l)(C) of RERA, every builder must disclose the carpet area of each apartment at the time of project registration. State RERA Rules, including Rule 4 and Rule 5 of the Maharashtra RERA Rules, make it clear that all advertisements, brochures, and sale agreements must quote and sell units solely on the basis of carpet area. Any reference to built-up or super built-up area must be accompanied by a clear explanation of how those figures are derived. Failure to comply with this requirement amounts to misrepresentation and can attract penalties under Section 61 of the Act, which empowers the Authority to impose fines up to five percent of the total project cost.

This legal shift ensures that all buyers now compare properties on a uniform basis. Whether you are buying a flat in Mumbai, Pune, or Delhi, the area mentioned under RERA will always refer to the actual usable carpet area. This not only brings consistency but also eliminates inflated or misleading sales tactics that were common before RERA.

The Three Percent Variation Rule - Buyer Protection in Practice

RERA also recognizes that minor variations can occur between the approved plans and the final constructed area. To address this, Rule 18 of the Maharashtra RERA Rules, 2017 provides that if the carpet area of an apartment is reduced by more than three percent from what was agreed upon in the sale agreement, the builder must refund the excess amount received with interest. If the reduction is less than three percent, the adjustment must be made proportionately at the same rate per square foot.

 For example, if a buyer was promised a carpet area of 1,000 square feet but received only 960 square feet upon possession, which is a four percent reduction, the buyer is entitled to a refund for the difference of 40 square feet along with applicable interest. This rule acts as a strong safeguard against post-construction manipulation of space.

Balconies, Terraces, and Open Spaces - What RERA Clarifies

Balconies, verandas, and open terraces are attractive features in any apartment, but they are often used by builders to create hidden costs. Under RERA, these spaces are explicitly excluded from carpet area calculations. However, a builder is allowed to sell these as exclusive areas provided that the exact measurements and per-square-foot pricing are clearly disclosed in the sale agreement. If a developer charges for balcony or terrace areas without proper disclosure, it amounts to suppression of material information and violates Section 4(2)(l)(C) of RERA. Buyers must carefully read their agreement to ensure these details are transparently presented.

Builder’s Disclosure Obligations Under RERA

When registering a project, every developer has a statutory obligation to disclose the carpet area of each unit, the area of balconies and terraces, the proportionate share of common areas, and the sanctioned layout plans. These details are uploaded to the State RERA portal for public viewing, ensuring transparency for every buyer. If any information is found to be false or incomplete, the Authority can impose heavy penalties under Section 61, suspend the project registration under Section 7, or order compensation under Section 18. These provisions ensure that builders cannot manipulate figures or conceal project details from the public.

Legal Precedents Supporting Carpet Area Regulation

The Authority categorically held that developers cannot charge or advertise prices based on super built-up area, and that the sale consideration must be linked exclusively to the carpet area as defined under Section 2(k) of RERA.

Similarly, in D.S. Kulkarni Developers Ltd. v. MahaRERA (2019), the Authority observed that failure to disclose the correct carpet area constitutes misrepresentation, and buyers are entitled to refunds with interest for discrepancies. These precedents highlight RERA’s strict stance against misleading marketing and confirm that the law protects buyers’ rights to transparency and accuracy.

Why This Distinction Matters - Financial and Legal Implications

Understanding these distinctions is crucial because they directly affect how much you pay and what you own. When a flat is sold on the basis of carpet area, you know exactly how much space is usable within your walls. But if you buy on a built-up or super built-up basis, you may unknowingly overpay by 20 to 30 percent for non-usable space. Legally, only the carpet area is recognized for the purpose of sale, registration, and calculation of stamp duty. Built-up or super built-up figures hold no legal standing under RERA and can expose builders to penalties if used for pricing. From a buyer’s perspective, this clarity ensures you receive fair value for every rupee spent and that your agreement reflects the true dimensions of your home.

The Concept of Undivided Share (UDS) of Land

Many homebuyers mistakenly believe that super built-up area includes ownership of common spaces. In reality, what a flat owner holds is an undivided share (UDS) of the total project land, proportionate to the carpet area of the unit.

Remedies Available to Buyers Under RERA

If a builder delivers a smaller carpet area than promised, misquotes built-up or super built-up area, or fails to disclose essential details, the buyer has strong remedies under RERA. You can file a complaint under Section 18 of the Act seeking refund, interest, and compensation. You can also invoke Section 31 to file a formal complaint before the RERA Authority or the Adjudicating Officer for non-compliance. If the builder’s misrepresentation amounts to an unfair trade practice, you may simultaneously approach the Consumer Forum for compensation under the Consumer Protection Act. RERA also empowers buyers to seek execution of refund or possession orders if the developer fails to comply voluntarily. In serious cases, the Authority can even revoke the builder’s registration.

Practical Guidance for Buyers Before Booking

Before booking a property, always insist on written confirmation of the carpet area and cross-check it with the project details available on the State RERA portal. Compare the area mentioned in the brochure with that registered under RERA, as many builders continue to market using inflated figures. Review your Agreement for Sale carefully to ensure that it mentions only carpet area and not built-up or super built-up area. Also confirm that the size and price of balconies, terraces, and open spaces are separately listed. If the delivered carpet area is reduced by more than three percent, claim a refund with interest immediately. Avoid projects that use the term “saleable area” without clear explanation, as this is not a recognized measure under RERA.

Common Misconceptions About Area Calculation

Several misconceptions persist among buyers. One common myth is that the super built-up area gives ownership rights over common amenities like clubhouses or lobbies. In truth, you only have a proportionate undivided share in the land, not exclusive ownership of these spaces. Another misconception is that built-up area can still be used for sale; this is incorrect, as RERA mandates carpet area as the sole legal basis for sale consideration. Buyers also often believe that balconies and terraces are included in carpet area, but they are specifically excluded and must be priced separately. Finally, some assume that builders can freely advertise using any measurement, whereas misleading area advertisements are punishable under RERA and can attract heavy penalties.

Key Takeaways

To summarize, carpet area represents the actual usable space inside your flat and is the only legally valid measure under RERA. Built-up area adds wall thickness and balcony space, while super built-up area includes common amenities and shared spaces. RERA has abolished the practice of selling based on super built-up area to ensure transparency and fairness. The three percent variation rule protects buyers from post-construction shrinkage of space. Balconies and terraces can be sold only if clearly disclosed. Buyers should always verify project details on their State RERA website before signing any document or making payment. Understanding these distinctions helps you avoid overpricing, false promises, and legal disputes, ensuring that the home you buy matches the value you pay.

How NyayKart Can Help

If your builder has sold you a flat on the basis of built-up or super built-up area, delivered less carpet area than promised, or failed to disclose key details, NyayKart’s experienced legal team can help you take immediate action. We assist buyers in reviewing agreements, comparing advertised and registered details, filing complaints under Sections 18 and 31 of RERA, seeking refunds or possession orders, and enforcing RERA judgments before the appropriate authorities. Our experts handle cases before MahaRERA and other State RERA Authorities across India.

If you’re facing a dispute or simply want clarity before investing, book a free consultation with NyayKart today. We’ll help you verify your property’s legal compliance, calculate the correct carpet area, and ensure that every square foot you pay for is rightfully yours.