An Assam bigha is 14,400 square feet — identical to West Bengal's — but Assam divides it into 5 katha of 2,880 square feet, while West Bengal uses 20 katha of 720. The bigha travels between the two states; the katha does not.
Assam is a useful case study in why converting the headline unit is not enough. Anyone comparing an Assam listing with a West Bengal one will find the bigha reconciles perfectly and conclude the two markets use the same system. They do not, and the unit that differs is the one prices are usually quoted in.
The Assam unit ladder
| Unit | Square feet | Relationship | Per acre |
|---|---|---|---|
| 1 lecha | 144 | 1/20 katha | 302.5 |
| 1 katha | 2,880 | 1/5 bigha | 15.125 |
| 1 bigha | 14,400 | 5 katha | 3.025 |
| 1 acre | 43,560 | 3.025 bigha | 1 |
The ladder is internally consistent: 20 lecha to a katha, 5 katha to a bigha. One bigha is 1,600 square yards, giving exactly 3.025 bigha to an acre — the same clean fraction as West Bengal, because it is the same bigha.
The katha trap
Four times the area, same word
An Assam katha is 2,880 square feet. A West Bengal katha is 720. A Bihar katha is about 1,361. All three are called a katha, and all three appear in listings across eastern India.This matters because katha is the practical unit in all three states. Residential plots, small agricultural parcels and per-unit prices are usually quoted in katha rather than bigha, so the unit that varies most is the one that appears most often in a negotiation.
| State | Katha (sq ft) | Katha per bigha | Bigha (sq ft) |
|---|---|---|---|
| Assam | 2,880 | 5 | 14,400 |
| West Bengal | 720 | 20 | 14,400 |
| Bihar | 1,361.25 | 20 | 27,225 |
| Jharkhand | 1,361.25 | 20 | 27,225 |
Bihar adds a further complication: its katha varies by district as well, from about 1,361 square feet near Patna to roughly 1,901 in Muzaffarpur and about 3,267 in West Champaran. The West Bengal guide covers the eastern katha family from the other side.
Beyond Assam
The bigha is not used uniformly across the northeast. Assam, with the region's largest area of settled agricultural plains, uses it consistently. In the hill states the picture is different, and for structural reasons rather than accidental ones.
- Tripura uses the bigha and katha, generally following the Bengal pattern given the shared history and border.
- Meghalaya, Nagaland, Mizoram and much of Arunachal Pradesh have significant community and clan land tenure, where holdings are described by boundary and customary right rather than by a surveyed area in traditional units.
- Manipur's valley districts use local measures including the sangam and the lourak, distinct from the bigha family.
- Where a formal figure is needed in the hill states, it is usually given directly in hectares or acres rather than converted through a traditional unit.
This is worth knowing because the absence of a bigha figure in a northeastern hill state is not a gap in the data — it reflects a genuinely different way of holding and describing land.
Assam conversions
| Area | Bigha | Katha | Square feet |
|---|---|---|---|
| 1 acre | 3.025 | 15.125 | 43,560 |
| 1 bigha | 1 | 5 | 14,400 |
| 1 katha | 0.2 | 1 | 2,880 |
| 1 hectare | 7.475 | 37.375 | 107,639 |
Assam is in the state dropdown on the acre to bigha calculator, which shows every result in square feet alongside the bigha figure — the fastest way to sanity-check a katha-denominated quote.
Practical checks
- If a price is quoted per katha, establish the state before you compare it with anything. A four-fold error is available here for free.
- Convert everything to square feet before comparing listings across state lines. The bigha reconciles; the katha does not.
- For Assam agricultural land, check whether the area is stated in the chitha or jamabandi and use that figure.
- In the hill states, expect areas in hectares or acres and treat any bigha conversion as informal.
The state comparison table lists Assam alongside West Bengal so the shared bigha and divergent katha are visible together. For the general principle behind this kind of divergence, see why bigha size varies by state.