One bigha in West Bengal is 14,400 square feet, or exactly 40/121 of an acre. One acre is 3.025 bigha. West Bengal is one of the few Indian states where the bigha is effectively standardised, which makes this figure unusually dependable.
West Bengal is the easy case. After the internal chaos of Uttar Pradesh and the pucca/kaccha split in Rajasthan, it is a relief to reach a state where one figure holds across the territory. The complication here is not the bigha — it is the katha inside it.
The figure, and why it is exact
A West Bengal bigha is 1,600 square yards. An acre is 4,840 square yards. Divide one into the other and you get 3.025 bigha per acre exactly — or, put the other way, one bigha is precisely 40/121 of an acre.
That the ratio comes out as a clean fraction rather than a rounded decimal is a good sign. It means the figure is being derived from the traditional definition in square yards rather than passed along as an approximation that has drifted through repetition.
| Unit | Square feet | Equivalent |
|---|---|---|
| 1 katha | 720 | 1/20 bigha |
| 1 bigha | 14,400 | 0.3306 acre |
| 1 acre | 43,560 | 3.025 bigha |
| 1 hectare | 107,639 | 7.475 bigha |
The katha is where deals go wrong
West Bengal divides a bigha into 20 katha of 720 square feet each. That is the local convention, it is consistent within the state, and for most West Bengal transactions it causes no trouble at all.
The trouble starts at the state line. Assam uses the same 14,400 square foot bigha, but divides it into five katha rather than twenty — so an Assam katha is 2,880 square feet, four times a Bengal katha. Bihar divides its much larger bigha into twenty katha of roughly 1,361 square feet. The Assam and northeast guide covers that divergence in detail.
The same word, four times the area
A price of ₹5 lakh per katha means one thing in Kolkata and something four times larger in Guwahati — despite both states using an identical bigha. If a quote crosses a state line, normalise it to square feet before comparing.Shatak, decimal and the other local units
Alongside the bigha and katha, West Bengal listings frequently use two more units that are worth recognising:
- Shatak (also written satak): one hundredth of an acre, 435.6 square feet. Because it is defined against the acre rather than the bigha, it converts cleanly and is a good unit to transact in.
- Decimal: used interchangeably with shatak in much of eastern India, also 1/100 of an acre.
- Chatak: 1/16 of a katha, 45 square feet. Turns up in urban plot descriptions in Kolkata.
If a seller offers you a figure in shatak or decimal, take it. Those units are anchored to the acre, which means they carry none of the regional ambiguity the bigha does.
The same bigha across the border
The 14,400 square foot bigha is not exclusively West Bengal's. Bangladesh uses the identical figure, also divided into 20 katha. This is a straightforward inheritance: the unit was settled under a single revenue administration before Partition, and neither side changed it afterwards.
For anyone dealing with land or family records on both sides of the border, this is one of the few conversions in the region that needs no adjustment at all.
Practical checks for a West Bengal purchase
- Confirm whether the quoted area is in bigha, katha, shatak or decimal — the four are common in the same market and differ by orders of magnitude.
- For any quote that originated outside West Bengal, convert to square feet before comparing. The katha in particular does not travel.
- Cross-check the listing area against the record of rights. The recorded area governs registration.
- For agricultural land, confirm whether the area includes or excludes ponds, embankments and access paths — this is a separate issue from unit conversion but affects the usable figure just as much.
The acre to bigha calculator has West Bengal in the state dropdown, and the state comparison table shows how the 14,400 square foot bigha sits against the rest of the country — roughly half the size of the Uttar Pradesh pucca bigha.