ModernCalcs

Carpet Area Converter

Convert between Carpet Area, Built-up Area, and Super Built-up Area for Indian real estate.

10010,000

Standard Loading Factors

We use a standard 15% loading for Built-up and 35% for Super Built-up. These may vary by builder.

Super Built-up Area (Saleable)
1,350 sq.ft

Area typically used for pricing by builders.

Built-up Area
1,150 sq.ft
Carpet Area (RERA)
1,000 sq.ft

Decoding Indian Real Estate Areas

When buying a flat in India, you will encounter three types of area measurements. Understanding the difference is crucial for calculating the true price per square foot.

1. Carpet Area

The actual area you can spread a carpet on. It includes the thickness of internal partition walls but excludes the balcony and external walls. This is the area mandated by RERA for all disclosures.

2. Built-up Area

Carpet Area + External Walls + Balcony + Terrace area. Usually, this is about 10-15% more than the Carpet Area.

3. Super Built-up Area

Built-up Area + Common Areas (Lobby, Lift shaft, Stairs, Club house). This is usually 25-40% higher than the Carpet Area.

Carpet Area to Super Built-up Area: The Complete Guide for Indian Home Buyers

When a builder quotes a price for a 1,200 sq ft apartment, what exactly are you paying for? In India, three different area definitions are in use — Carpet Area, Built-up Area, and Super Built-up Area — and confusing them can lead to a 20–30% surprise on your actual usable space. Our converter lets you translate between these three types instantly using industry-standard loading factors.

Formula
Super Built-up Area = Carpet Area × Loading Factor

The loading factor typically ranges from 1.20 to 1.40 depending on the project. RERA mandates that builders disclose the RERA Carpet Area.

Carpet Area: What You Actually Use

Carpet area is the net usable floor space inside your apartment — the area where you can literally lay a carpet. It includes the area covered by internal partition walls but excludes the thickness of external walls, balconies, and common areas. Under RERA, this is the legally mandated area that must be disclosed in all sale agreements. If a builder quotes you a price per sq ft, always ask whether it is on carpet area basis.

Built-up Area: Adding the Walls

Built-up area = Carpet Area + the thickness of external walls + the balcony area. This is typically 10–15% more than the carpet area. It represents the total footprint of your private space within the building, but still excludes common areas like corridors, stairs, and the lobby.

Super Built-up Area: The Builder's Metric

Super Built-up Area (also called Saleable Area) = Built-up Area + your proportionate share of common areas (lift, lobby, generator room, gym, etc.). This is the number builders use to quote prices, because it is always the largest of the three. The ratio of Super Built-up to Carpet area is called the Loading Factor or Loading Percentage. A loading factor of 1.3 means for every 100 sq ft of carpet area, you are paying for 130 sq ft.

How to Evaluate a Builder's Loading

A loading factor above 1.35 should raise a flag — it means 35%+ of what you are paying for is common areas. Compare the loading factor across projects in the same area. Premium projects with large lobbies and multiple amenities naturally have higher loading, but anything above 1.4 in a mid-range project suggests inflated common-area claims. Under RERA, you can verify the carpet area on the registered sale agreement and cross-check it against the builder's stated Super Built-up.

Practical Examples

Evaluating a 3BHK Quote

Builder quotes 1,500 sq ft Super Built-up at ₹7,000/sq ft — what is the real carpet area?

  • 1.Super Built-up: 1,500 sq ft
  • 2.Assumed loading factor: 1.30
  • 3.Carpet Area = 1,500 / 1.30 = 1,154 sq ft
  • 4.Effective price per carpet sq ft = ₹7,000 × 1.30 = ₹9,100
  • 5.Always negotiate on carpet area price, not super built-up.

Comparing Two Projects

Project A: 900 sq ft carpet at ₹8,500/sq ft. Project B: 1,200 sq ft super built-up at ₹6,000/sq ft with 1.3 loading.

  • 1.Project A: Carpet = 900 sq ft, Cost = ₹76.5 L
  • 2.Project B: Carpet = 1,200 / 1.3 = 923 sq ft, Cost = 1,200 × 6,000 = ₹72 L
  • 3.Project B is cheaper but has only 23 sq ft more carpet area.
  • 4.Factor in amenity quality and builder reputation before deciding.

Key Terms to Know Before Signing

  • RERA Carpet Area: Legally defined, excludes balconies and external walls.
  • Loading Factor: Super Built-up ÷ Carpet Area. Lower is better for the buyer.
  • Undivided Share (UDS): Your proportionate ownership of the land, important for resale.
  • Plinth Area: Same as Built-up Area in most contexts; the ground-floor footprint.
  • FSI / FAR: Floor Space Index — the ratio of total built area to plot area, regulated by municipalities.

Home-Buying Checklist

  • Ask for RERA carpet area in writing before any payment.
  • Calculate the loading factor and compare it across at least 3 projects.
  • Check the RERA registration number on the state RERA portal.
  • Verify the common areas listed in the agreement match the project's actual amenities.
  • Negotiate on carpet area price, not super built-up.

Frequently Asked Questions

What is Carpet Area?

Carpet area is the net usable floor area of an apartment, excluding the area covered by the external walls but including internal partition walls.

What is Super Built-up Area?

It is the built-up area plus proportionate common areas like the lobby, lift, and stairs. This is usually what builders charge for.

What is RERA carpet area?

RERA carpet area is the net usable floor area of an apartment excluding balconies and external walls, which builders must disclose by law.

What is a typical loading factor in India?

Loading factors vary between 1.2 and 1.4 depending on the builder and project. A factor of 1.3 means Super Built-up Area is 30% more than Carpet Area.

Why does RERA require carpet area disclosure?

Before RERA (2016), builders often sold units on a Super Built-up basis without disclosing the actual usable area, making it hard to compare prices. RERA mandates carpet area disclosure for transparency.

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