An apartment advertised as “1,000 sq ft” might only give you around 700-750 sq ft you can actually furnish. That’s not a scam – it’s three different area measurements getting compressed into one marketing number, and the gap between them is exactly where buyers get caught comparing properties that aren’t really comparable. Before you price-compare anything, run the raw dimensions through the CalcRange Area Calculator and make sure you know which figure you’re actually looking at.
Key Takeaways
- Carpet area is the actual usable floor space inside the walls of a unit – the area you could literally lay a carpet on.
- Built-up area adds the thickness of the unit’s own walls on top of carpet area.
- Super built-up area adds a proportional share of shared spaces like lobbies, stairwells, and corridors – and is the figure most often advertised.
- The gap between super built-up and carpet area commonly falls in the range of roughly 25-35% in many markets.
- India’s RERA regulation specifically requires developers to sell based on carpet area, addressing this exact confusion.
Carpet Area: What You Actually Get
Carpet area is the literal usable floor space inside the interior walls of a unit – the area you could actually cover with carpet, excluding the thickness of the walls themselves. It’s the most honest measurement of what you’re actually paying to live in, and it’s the number that tells you whether your furniture will actually fit, not the number that shows up largest on a marketing brochure.
Built-Up Area: Adding the Walls
Built-up area, sometimes called plinth area, takes carpet area and adds the thickness of the unit’s own internal and external walls. Since walls take up physical space but aren’t usable floor area, built-up area is always larger than carpet area for the identical unit – the gap reflects how much of the unit’s footprint is structural rather than livable.
Super Built-Up Area: Adding Shared Space
Super built-up area goes a step further, adding a proportional share of common areas the resident doesn’t exclusively use – lobbies, stairwells, elevators, corridors, and often shared amenities. This is typically the figure developers advertise and price per square foot against, even though a meaningful chunk of it is space you’ll walk through rather than space you’ll actually live in.
| Measurement | What It Includes |
|---|---|
| Carpet area | Usable floor space inside interior walls |
| Built-up area | Carpet area + the unit’s own wall thickness |
| Super built-up area | Built-up area + a share of shared/common spaces |
The “Loading Factor” Gap
The difference between super built-up area and carpet area is often referred to as the loading factor, and in many markets it commonly falls somewhere in the range of roughly 25-35%, though this varies significantly by building, amenities, and developer. That means a unit advertised at 1,000 sq ft super built-up might carry a carpet area closer to 650-750 sq ft – a substantial gap between the number on the brochure and the number that actually determines how your furniture fits.
Compare the Real Numbers
Use the CalcRange Area Calculator to work out actual room dimensions once you have the carpet area figure, so you can plan furniture layout against real usable space rather than the marketed total. Our guide on how to calculate area covers the formulas for irregular room shapes if your layout isn’t a simple rectangle.
Why Regulators Stepped In
India’s Real Estate Regulatory Authority (RERA), introduced in 2016, specifically mandated that developers must quote and sell property based on carpet area rather than super built-up area, precisely because the gap between the two had become a persistent source of buyer confusion and disputed comparisons across projects. The regulation doesn’t eliminate super built-up area as a concept – it’s still used for pricing per square foot in practice – but it does require carpet area to be clearly and accurately disclosed alongside it, giving buyers a reliable figure to actually compare.
Frequently Asked Questions
What’s the difference between carpet area and built-up area?
Carpet area is the usable floor space inside a unit’s interior walls. Built-up area adds the thickness of the unit’s own walls on top of that, so it’s always a larger figure for the same unit.
Why is super built-up area usually the number advertised for a property?
Because it’s the largest of the three figures, since it includes a proportional share of common building spaces like lobbies and corridors in addition to the unit’s own built-up area, and pricing per square foot against a larger number can make a unit seem more competitively priced.
How much smaller is carpet area compared to super built-up area?
It varies by building and developer, but a commonly cited range is roughly 25-35% smaller, meaning the usable space can be considerably less than the advertised total.
Does RERA require developers to disclose carpet area?
Yes, in India specifically – RERA requires developers to quote and sell based on carpet area, addressing the confusion that arose from super built-up area being the primary advertised figure.
Should I compare properties by price per square foot of carpet area or super built-up area?
Comparing based on carpet area gives a more accurate sense of what you’re actually paying for usable space, since super built-up area can vary in how much shared space it includes between different buildings and developers.
Is built-up area the same as carpet area plus balconies?
Not exactly – built-up area specifically adds wall thickness to carpet area. Balconies and other semi-covered spaces are typically accounted for separately or partially, depending on local measurement conventions, so it’s worth clarifying exactly what’s included when comparing figures.
The Bottom Line
The square footage on a property listing depends entirely on which of three different measurements is being used, and they can differ by a quarter or more of the total. Ask specifically for carpet area before comparing price per square foot across properties – it’s the only one of the three that tells you what you’re actually going to live in.
Last reviewed: August 2026