# Carpet Area Calculator: Carpet, Built-Up and Super Built-Up

> Carpet area is the usable floor inside your walls. Built-up area adds the walls. Super built-up (chargeable) area adds a share of the building's common areas, which is the loading. With the loading known, any one of the three can be converted to the other two.

## What it calculates

Enter any one of the three areas and the converter gives the other two, with:

- the **carpet area** you can actually fit out and furnish;
- the **built-up area**, which adds the walls;
- the **super built-up area**, which adds a share of the common areas;
- the **efficiency**, carpet area as a percentage of super built-up area;
- each area in **square metres**;
- optionally, what a rent quoted on super built-up area **comes to on carpet area**.

## Inputs

**The area you know** is whichever figure the landlord or broker has given you. Leasing
proposals usually quote super built-up area.

**Area** is that figure, in square feet.

**Loading** is the share of common area charged on top of carpet area, as a percentage of
carpet area. Ask the landlord for it, or work it out from a floor's carpet and super
built-up figures.

**Rent quoted on super built-up** is optional. Enter the monthly rent for each square foot of
super built-up area to see the equivalent on carpet area.

The **wall allowance** in the assumptions panel sets how much larger built-up area is than
carpet area.

## Method

The converter uses the same loading definition as our glossary page on carpet and built-up
area:

- Super built-up area = carpet area × (1 + loading).
- Built-up area = carpet area × (1 + wall allowance).
- Efficiency = carpet area ÷ super built-up area.
- Rent on carpet area = rent on super built-up area × (1 + loading).

When you enter super built-up or built-up area, the converter first works back to carpet
area by dividing by the matching factor, then works forward to the others.

## Assumptions

| Assumption | Default | Notes |
| --- | --- | --- |
| Loading | 30% | Replace with the building's real figure |
| Wall allowance | 10% | Internal and external walls, and balconies where counted |
| Square metres | 1 sq ft = 0.092903 m² | Exact conversion |

The wall allowance only affects the built-up figure. Built-up area is rarely used in office
leasing, but it appears in some sale documents and older agreements, so the converter shows
it for completeness.

## Limitations

- **Loading is not standard.** Definitions differ between landlords, and the same building
  can quote different loading on different floors. Use the figure from your own lease or
  proposal.
- **Carpet area under RERA is defined for sale of registered projects.** RERA 2016 Section
  2(k) gives the statutory definition: the net usable floor area within the walls, excluding
  external walls, service shafts, balconies and verandas, but including internal partition
  walls. A commercial lease uses whatever definition the lease itself sets out.
- **Usable is not the same as efficient.** Carpet area includes awkward corners, column
  zones and deep floor areas far from windows. A floor with the same carpet area can hold
  more or fewer desks depending on its shape.
- **Measured area can differ from the stated area.** If the figure matters to the rent, ask
  for a measurement survey.

## Worked example

A broker quotes an office floor of 10,000 sq ft super built-up. The landlord confirms 30%
loading. Using a 10% wall allowance:

| Figure | Calculation | Result |
| --- | --- | --- |
| Carpet area | 10,000 / 1.30 | 7,692 sq ft (715 m²) |
| Built-up area | 7,692 × 1.10 | 8,462 sq ft (786 m²) |
| Super built-up area | 7,692 × 1.30 | 10,000 sq ft (929 m²) |
| Efficiency | 7,692 / 10,000 | 76.9% |

Only 7,692 sq ft is available for desks, cabins and meeting rooms. At the 93 sq ft of carpet
for each person in the office space planner's worked example, that holds a team of about 80,
not the 107 that the same density would suggest if it were applied to the 10,000 sq ft
headline.

If the rent is quoted at a given figure for each sq ft of super built-up area, the rent for
each sq ft of carpet area is 1.3 times that figure, 30% higher than it first appears.

## How engineers use it

Designers and project managers work in carpet area throughout: the space plan, the
workstation count, the fit-out quantities and the cooling load all follow the area that is
actually fitted out. Converting the landlord's figure to carpet area is usually the first
calculation on any new office project, before a test fit is drawn.

## When a professional design must replace it

Use the converter to compare buildings on the area you can actually use and to understand
what a rent quote means. Before you sign, get the carpet area for the specific floor in
writing, check how the lease defines each area, and have a designer test fit the floor so
you know the area works for your team, not just that it adds up.

## Frequently asked questions

### How do I convert super built-up area to carpet area?

Divide the super built-up area by one plus the loading. At 30% loading, 10,000 sq ft super built-up gives 10,000 / 1.30, about 7,692 sq ft of carpet. Ask the landlord for the loading, or for the carpet area directly, because loading varies from building to building.

### What is a typical loading for an office building?

Grade-A commercial buildings in India commonly load somewhere between 25% and 40%, but it is a building-specific figure and a lease term, not a standard. Buildings with large lobbies, deep cores and generous common areas sit at the upper end.

### Why does loading matter for rent?

Rent is usually quoted on super built-up area, but you can only use the carpet area. The higher the loading, the more you pay for each square foot you can actually use. The calculator shows that effective figure if you enter the quoted rent.

### Which area should a fit-out quote use?

Carpet area, because the fit-out happens inside your space. A fit-out price expressed on super built-up area looks lower than the same price on carpet area, so always confirm which area a quote uses before comparing.

### Is the loading definition the same everywhere?

No. Some landlords express loading as a percentage of carpet area, which this calculator uses, and some as the share of super built-up area that is common. Others quote an efficiency instead. Check how your lease defines it and convert before using the figure.

## Sources

- [RERA 2016](https://legislative.gov.in/) — Section 2(k): definition of carpet area

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Source: https://hagerstone.com/calculators/carpet-area-calculator