The loading factor
Loading is the percentage a developer adds to a flat's own area to arrive at the saleable figure. A 25% loading on a 700 sq ft built-up area gives 875 sq ft; a 40% loading gives 980 sq ft for exactly the same flat. There is no statutory ceiling on the loading factor, and it varies by project according to how much amenity the developer built — and how much they chose to charge for.
| Building type | Typical Mumbai loading | Carpet as % of super built-up |
|---|---|---|
| Older society, minimal amenities | 18–25% | 75–82% |
| Standard new tower | 28–35% | 66–72% |
| Premium tower with clubhouse and podium | 35–45% | 58–65% |
| Redevelopment project | 25–35% | 68–75% |
What RERA changed
Before 2016, flats were advertised and sold on super built-up area with no standard definition of what it included, and two projects quoting the same number could deliver materially different flats. The Real Estate (Regulation and Development) Act 2016 requires the RERA carpet area to be stated in the agreement and in advertising for registered projects. Super built-up area has not disappeared — brokers and listings still use it — but the agreement now has to carry the carpet figure.
The figure follows you after purchase, because society maintenance charges are usually billed per square foot of super built-up area rather than carpet. A 30% loading therefore adds 30% to your monthly outgoings for the life of the flat — worth knowing when comparing two buildings with similar carpet areas.
Never quote interiors against it
A ₹19 lakh interior project on a 1,000 sq ft carpet flat is ₹1,900 per sq ft. Quoted against a 1,450 sq ft super built-up figure, it reads ₹1,310 — and next to a competitor honestly quoting ₹1,900 on carpet, it looks 31% cheaper for identical work. This is the single most common apples-to-oranges comparison in Indian interior pricing. Convert everything to carpet area first with the area converter, then compare. See interior design cost.
Frequently asked questions
Is super built-up area legal?+
Using it is not prohibited, but under RERA a registered project must state the carpet area in the agreement and in advertising. Marketing material and broker listings may still quote super built-up alongside it.
What is a typical loading factor in Mumbai?+
28–35% in a standard new tower, rising to 45% in premium projects with large podiums and clubhouses, and falling to around 20% in older societies with minimal common area. Always ask the developer for the figure directly.
How do I convert super built-up to carpet area?+
Divide by one plus the loading factor. At 30% loading, a 1,300 sq ft super built-up flat has roughly 1,000 sq ft of carpet area. If the developer will not state the loading factor, that is itself informative.
Why do brokers still quote super built-up area?+
Because the number is larger and the resulting per-sq-ft price looks lower. It is also the convention buyers have been trained on for thirty years. Read the agreement, which must carry the carpet figure.