Carpet Area Calculator
Measure each room inside the walls, add the internal partition walls and any balconies, and the carpet area calculator gives the total under the convention you pick, listing every part it counted or left out.
Carpet area calculator
Area definitions differ by country, authority and contract. This calculator applies the convention you choose; the area in your agreement is the one that counts.
Walls between rooms inside the flat, added up. Not the outer walls. Enter 0 to leave them out.
RERA-style follows the wording of the carpet-area definition in India’s Real Estate (Regulation and Development) Act, 2016, section 2(k), as we read it: rooms plus internal partition walls; external walls, service shafts, exclusive balconies, verandahs and open terraces excluded. State rules and your agreement may add detail; check the current text.
Leave blank for room 1.
Assumptions
Change any value to match your product or local rules.
Basis: Example only. Measure your walls.
- Carpet area (your convention)
- 58.57 m²
- 630.4 sq ft
- Rooms
- 56.73 m²
- 610.6 sq ft
- Internal walls
- 1.84 m²
- 19.8 sq ft
- Balconies, verandahs, terraces
- 4.00 m²
- 43.1 sq ft
Carpet area under this convention: 58.57 m² (630.4 sq ft).
Counted
- Rooms: 56.73 m² (610.6 sq ft)
- Internal walls: 1.84 m² (19.8 sq ft)
Not counted
- Balconies, verandahs and terraces: 4.00 m² (43.1 sq ft)
- External walls and service shafts: not entered here, so not counted
Design this room
- Opens Room 1, whose inside is 5.00 m × 3.60 m. The editor measures walls on their centre lines, so the link adds one wall thickness (0.15 m) to the width and to the length.
How this was calculated
- Rooms = Σ width × length (each measured wall face to wall face)
- Internal walls = total partition length × wall thickness
- Balconies = Σ width × length
- Carpet area = rooms + the parts your convention includes
- Rooms = 5.00 m × 3.60 m + 3.60 m × 3.30 m + 3.30 m × 3.00 m + 3.00 m × 2.40 m + 2.40 m × 1.50 m + 2.10 m × 1.50 m + 3.00 m × 1.00 m = 56.73 m²
- Internal walls = 16.00 m × 115 mm = 1.84 m²
- Balconies = 2.00 m × 2.00 m = 4.00 m²
- Carpet area = rooms 56.73 m² + walls 1.84 m² = 58.57 m²
How the calculator works it out
Rooms
Each room is width × length, measured from wall face to wall face at floor level. The rooms are added up.
Internal walls
The walls between rooms inside the flat are entered as one total length; length × thickness gives the floor they stand on.
Balconies and terraces
Exclusive balconies, verandahs and open terraces are measured the same way but kept as a separate figure.
Your convention
The convention decides which of those figures make up the carpet area. Everything left out is listed under “Not counted”, so you can compare with a listing.
What carpet area means, and why definitions differ
Carpet area is the floor you can use inside a flat: roughly, the area a wall-to-wall carpet would cover. Definitions disagree on the edges. Some count the floor under the walls between your rooms and some leave it out; some definitions also include balconies, so check your documents; service shafts, ducts and external walls stay out.
In India, the Real Estate (Regulation and Development) Act, 2016 defines carpet area in section 2(k) as the net usable floor area of an apartment, excluding external walls, service shafts, exclusive balconies or verandahs and exclusive open terraces, but including internal partition walls. The “RERA-style” option follows that wording as we read it. Elsewhere the same idea goes by names such as net internal area, and the rules for measuring it come from the surveyor, the authority or the contract. That is why the calculator asks you to choose, and why the agreement you sign decides which figure counts.
Measuring each room
Measure inside the walls
Run the tape from one finished wall face to the opposite one, at floor level, ignoring skirting boards. Do both directions before you move on.
Split odd shapes
Enter an L-shaped room as two rectangles, and a passage or utility area as its own row. Every row is added up.
Total the partition walls
Walk the flat and add up the length of every wall between two rooms. Leave out the outer walls and walls shared with the neighbours.
Measure the wall thickness
At a door frame you can see the wall’s full thickness. The 115 mm default is an example; plastered brick and drywall partitions differ.
Worked example: a two-bedroom flat
A living room 5.0 × 3.6 m (18.0 m²), bedrooms 3.6 × 3.3 m (11.88 m²) and 3.3 × 3.0 m (9.9 m²), a kitchen 3.0 × 2.4 m (7.2 m²), bathrooms 2.4 × 1.5 m (3.6 m²) and 2.1 × 1.5 m (3.15 m²) and a passage 3.0 × 1.0 m (3.0 m²) add up to 56.73 m², about 610.6 sq ft.
The partition walls between them total 16 m at 115 mm thick: 16 × 0.115 = 1.84 m². Under the RERA-style convention the carpet area is 56.73 + 1.84 = 58.57 m², about 630.4 sq ft. A 2.0 × 2.0 m balcony (4.0 m², about 43.1 sq ft) is shown as not counted.
The same works in feet: a 12 × 10 ft room is 120 sq ft, about 11.15 m². You can mix units in one list; type 3.6 m in imperial mode or 12' in metric mode and it converts.
Carpet, built-up and super built-up area
| What it includes | Where it comes from | |
|---|---|---|
| Carpet area | Usable floor inside the flat (the convention decides the edges) | Measured room by room, as on this page |
| Built-up area | Carpet area plus walls; some definitions also include balconies | Measured to the outer faces of the flat’s walls, or stated by the builder |
| Super built-up area | Built-up area plus a share of common areas (lobby, stairs, lift) | Stated by the builder as a loading on built-up or carpet area |
Checking a listing or an agreement
A listing may quote the super built-up area, which includes common parts of the building. To see how much of it is yours to use, measure the carpet area here, then put the listed figure into the super built-up area calculator with the loading from the builder’s documents: the two carpet figures should agree. If they are far apart, ask which areas, walls and balconies the builder counted.
“Design this room” opens any room from your list in the floor plan editor. The editor draws walls on their centre lines, so the link adds one wall thickness (150 mm / 6 in) to the width and to the length, and the room’s inside matches what you measured.
Frequently asked questions
How is carpet area calculated?
Measure each room inside the walls and multiply width by length, then add the rooms together. Depending on the convention, add the floor under the internal partition walls (their total length × thickness). Service shafts and external walls stay out. Some definitions also include balconies or terraces; check your documents.
Does carpet area include walls?
External walls, no. Internal partition walls depend on the definition: India’s RERA wording includes them, while “rooms only” measurements leave them out. Choose the convention your agreement uses; the calculator shows the wall area separately either way.
Is a balcony included in carpet area?
Under the RERA-style convention, exclusive balconies, verandahs and open terraces are not. Some contracts quote them alongside the carpet area. Use the Custom convention to include them if your documents do.
What is the difference between carpet, built-up and super built-up area?
Carpet area is the usable floor inside, including internal partition walls under India’s RERA definition. Built-up area adds the external walls and shafts, and some definitions also include balconies. Super built-up area adds a share of the building’s common areas on top, through a loading percentage.
How do I convert carpet area to sq ft?
Multiply square meters by about 10.764, or divide square feet by 10.764 to get square meters (one square foot is exactly 0.09290304 m²). The calculator shows both.
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