Indian land measurement units, and what each one is worth
India uses two kinds of land unit, and confusing them is where most conversion mistakes come from. Some are fixed everywhere: a gaj is always 9 square feet, a guntha always 1,089, an acre always 43,560. Others — bigha, katha and biswa above all — have no single national size and mean different areas in different states. Convert the first kind with a formula; for the second, you have to know which region you are talking about.
The units that are the same everywhere
These have one exact value, so a conversion is arithmetic and nothing else. Square feet is used as the pivot because every one of them divides into it cleanly.
| Unit | Square feet | Roughly |
|---|---|---|
| 1 Gaj (square yard) | 9 | a bath mat |
| 1 Sarsahi | 30.25 | a parking space |
| 1 Chatak | 45 | |
| 1 Dhur | 68.06 | |
| 1 Ankanam | 72 | |
| 1 Lecha | 144 | |
| 1 Marla | 272.25 | a small room |
| 1 Decimal (or Cent) | 435.6 | |
| 1 Are | 1,076.39 | 100 square metres |
| 1 Guntha | 1,089 | |
| 1 Nali | 2,160 | |
| 1 Ground | 2,400 | |
| 1 Kanal | 5,445 | an eighth of an acre |
| 1 Acre (or Killa, Ghumaon) | 43,560 | about a football pitch |
| 1 Hectare | 107,639.10 | 2.47 acres |
Same unit, different name
Killa and Ghumaon are both other names for an acre — 43,560 square feet — which is why a conversion between them is always 1:1.
The units that change size by state
Bigha, katha and biswa are the ones to be careful with. They are older, locally defined measures, and there is no national standard to appeal to. A katha in West Bengal is 720 square feet; in Assam it is 2,880 — four times larger, for the same word.
This matters commercially. If a listing says "5 katha" and you assume the wrong region, you are out by a factor of four. Always establish which local value the seller, the deed or the revenue record is using before you convert anything.
- Bigha
- Ranges from 6,804 square feet in Uttarakhand to 27,225 in the standard pucca measure — a fourfold spread. Punjab and Haryana, Himachal, West Bengal, Madhya Pradesh, Gujarat and Uttar Pradesh all use their own value, and Rajasthan has separate pucca and kachha ones.
- Katha
- Commonly 1,361.25 square feet in Bihar and Jharkhand, 720 in West Bengal, 600 in Madhya Pradesh and 2,880 in Assam.
- Biswa
- Usually one twentieth of a bigha, so it inherits every one of the bigha’s regional variations.
How to convert between any two of them
Go through square feet. Multiply by the square feet in your starting unit, then divide by the square feet in the unit you want:
The formula
area in new unit = area × (square feet per old unit) ÷ (square feet per new unit)
So 2 acres in guntha is 2 × 43,560 ÷ 1,089 = 80 guntha. The same formula works for every pair in the table above, which is exactly what the app does — the difference being that it already holds the regional values, so you do not have to look them up.
Common questions
How many square feet is 1 gaj?
Exactly 9 square feet. A gaj is a square yard, and a yard is 3 feet, so 3 × 3 = 9. This one is the same everywhere.
How many guntha are in 1 acre?
Exactly 40. An acre is 43,560 square feet and a guntha is 1,089, and 43,560 ÷ 1,089 = 40.
Which land units change depending on the state?
Bigha, katha and biswa. The rest — gaj, guntha, acre, hectare, kanal, marla and so on — have one fixed value nationally.
Is there a single correct size for a bigha?
No. It is a local unit, and it ranges from roughly 12,000 square feet to 27,225 depending on the state and on whether the pucca or kachha measure is meant. Any source giving one figure without naming a region is oversimplifying.