Carpet Area vs Built Up Area vs Super Built Up, Plus Gaj, Marla, Cent and Bigha

Carpet area vs built up area vs super built up: the short answer

Carpet area is the floor you can actually walk on inside your home, measured wall to wall. Built-up area is carpet plus the thickness of the walls plus balconies and utility areas. Super built-up area is built-up plus your share of common areas like the lobby, staircase, lift and club house. As a thumb rule, built-up is 10 to 15 percent above carpet, and super built-up is 20 to 35 percent above carpet.

The same flat can therefore be sold as 900 sq ft carpet, 1,020 sq ft built-up or 1,200 sq ft super built-up. Under RERA, builders must quote carpet area in the agreement, but brochures still lead with the bigger number.

For an independent house the question is simpler. There are no common areas, so super built-up does not exist. Contractors and our own quotes use built-up area, measured to the outside face of external walls, floor by floor. This is the area our pillar guide on house construction cost per sq ft in India in 2026 applies its rates to.

How each area is measured

Carpet area

RERA defines carpet area as the net usable floor area of an apartment, excluding external walls, service shafts, balconies and open terraces, but including internal partition walls. So a wardrobe niche counts, a balcony does not. Before RERA many builders excluded internal walls too, so older documents may show a smaller carpet figure for the same flat.

Built-up area

Built-up, sometimes called plinth area, is measured to the external face of the outer walls. It includes all wall thickness, balconies and utility areas, and in a house, the staircase and any covered porch. With 9 inch external and 4.5 inch internal walls, walls alone take 8 to 12 percent of a small house.

Super built-up area

This is built-up plus a loading factor for common areas. Loading is a percentage the builder decides, commonly 20 to 35 percent, with no standard formula, which is why RERA stepped in. Loading of 15 to 20 percent means a lean project; above 35 percent means large amenities or an inefficient design where you pay for corridors. When a project quotes only super built-up, ask for carpet area in writing.

Why the distinction changes your money

For a flat, convert every quote to carpet area before comparing. A flat at Rs 6,000 per sq ft super built-up with 30 percent loading is Rs 7,800 per sq ft on carpet. Another at Rs 7,000 per sq ft on carpet is cheaper, though it looks dearer in the brochure.

For a house, contractors quote per sq ft of built-up area and measure every floor to the outer wall face. Quotes on plot area or carpet area are not comparable and usually hide a higher real rate. Our construction cost calculator works on built-up area so you compare on the same base.

Plot area, FAR and what you can actually build

Plot area is the land you own, from the sale deed and verified by survey. It is not the area you can build. Setbacks reduce the footprint, and FAR caps the total built-up across floors. A 30x40 plot of 1,200 sq ft with FAR 1.5 allows 1,800 sq ft built-up, perhaps 1,500 to 1,600 sq ft carpet, and that is what your family actually lives in.

The rules that convert plot area to buildable area are in our guide to building bye laws, FAR and setbacks. The point here is that plot, built-up and carpet are three different numbers, and a per sq ft rate applied to the wrong one is wrong by 20 to 50 percent.

Indian land units converted to sq ft

Plots are sold in local units across India: gaj in the north, marla in Punjab and Haryana, cent in Kerala and Tamil Nadu, guntha in Maharashtra and Karnataka, bigha across the Hindi belt and the east. Converting to sq ft is the first step in any plan or cost discussion.

The ones that matter for house plots are gaj, marla and cent, because those are the sizes people search for and buy. A 100 gaj plot is 900 sq ft, a 5 marla plot is about 1,361 sq ft, and a 5 cent plot is 2,178 sq ft. If you are planning a 100 gaj home, our 100 gaj house plan guide walks through layouts, and our collection of 100 gaj house plans shows ready designs.

In the south, cents work the same way. A 5 cent plot gives a comfortable 3 BHK with a garden; our 5 cents house plan guide covers 3, 5 and 10 cent layouts, and the 5 cents house plans hub has sample designs with Kerala style roofs.

Bigha: the unit with no single answer

Bigha causes the most confusion because every state, and often every district, has its own value. Our urban planner's rule for clients: never convert bigha from memory, always check the sale deed, which usually also states the area in sq m or hectares.

• Uttar Pradesh: a pucca bigha is about 27,000 sq ft in western UP, while eastern districts often use a kuccha bigha near 6,800 sq ft.
• Bihar and Rajasthan (pucca): about 27,200 sq ft. Rajasthan kuccha bigha: about 17,400 sq ft.
• Madhya Pradesh: about 12,000 sq ft, though districts vary.
• West Bengal and Assam: about 14,400 sq ft, one third of an acre.
• Himachal and Uttarakhand: about 8,700 to 9,100 sq ft. Gujarat: about 17,400 sq ft.

The spread is nearly four times between the smallest and largest bigha. A farmhouse plot quoted at 2 bigha could be a third of an acre or over an acre. Get the deed figure in sq m and convert from that.

Quick conversion formulas and a worked example

1. Sq ft to sq m: divide by 10.764. Sq m to sq ft: multiply by 10.764.
2. Gaj to sq ft: multiply by 9. Marla to sq ft: multiply by 272.25. Cent to sq ft: multiply by 435.6.
3. Acre to sq ft: multiply by 43,560. Acre to cent: multiply by 100. Acre to guntha: multiply by 40.
4. Carpet to built-up for a house: multiply by about 1.12. Carpet to super built-up for a flat: multiply by 1.2 to 1.35.

Worked example. A plot is sold as 133 gaj in Ghaziabad. That is 133 x 9 = 1,197 sq ft, close to a 30x40 plot. With FAR 1.5 the maximum built-up is about 1,800 sq ft across floors, and at a 2026 standard rate of Rs 2,000 per sq ft the build costs about Rs 36 lakh. The carpet area the family lives in will be around 1,580 sq ft. Our 1200 sq ft house plan guide shows what fits on that footprint.

The same plot was described with four numbers: 133 gaj, 1,197 sq ft, 1,800 sq ft built-up and 1,580 sq ft carpet. Each is right in its own context. Mistakes happen when a price per sq ft from one context is applied to a number from another.

Next step: get your plot measured and planned

Send us your plot dimensions in any unit, gaj, marla, cent or sq ft, along with your city. Our team will convert it, apply the likely setbacks and FAR, and tell you the built-up and carpet area you can expect, before you spend on drawings. Start with our floor plan design service, or call +91 73165 33888 for a free first consultation.