The bigha (also formerly beegah; Hindi: बीघा, Assamese: বিঘা, Bengali: বিঘা) is a traditional unit of measurement of area of a land, commonly used in Nepal, Bangladesh and in a number of states of India, including Uttarakhand, Maharashtra, Haryana, Himachal Pradesh, Punjab, Madhya Pradesh, Uttar Pradesh, Bihar, West Bengal, Assam, [[Gujarat 1 bigha) and Rajasthan but not in southern states of India. There is no "standard" size of bigha. The size of a bigha varies considerably from place to place. Sources have given measurements ranging from 1,500 to 6,771 square metres (16,150 to 72,880 sq ft), but in several smaller pockets, it can be as high as 12,400 square metres (133,000 sq ft). Its sub-unit is Biswa (or Bisa) or Katha (or Katta) in many regions. Again there is no "standard" size of biswa or katha. A bigha may have 5 to 200 biswa in different regions.

In India, bigha ceased to be an official unit of area in 1957 when square metre or hectare (10,000 square metre) became the official legal unit of area of land.

Uses in India

The bigha is a traditional unit of land in several parts of South Asia. Sale and purchase of land (particularly agricultural land) is still done unofficially in this unit. However, the area is recorded in hectare or square metres in official land records. Bigha varies in size from one part of India to another. Various states and often regions within the same state have different sizes attributed to the bigha. It is usually less than one standard acre (4,840 square yard or 4,047 square metre) but can extend up to 3 acres (1.2 hectare).

In Assam, a bigha is 14,400 square feet (1,340 m^{2}), subdivided into five katha. Each katha consists of 20 lecha with a lecha covering 144 square feet (13.4 m^{2}) in area. Hence each katha is 2,880 square feet (268 m^{2}) in area, although this may vary within different regions of Assam. According to Department of land resources of India 1 Bigha (Assam) = 5 Katha = 100 Lessa = 14,400 square feet = 1,338 square metre.

In Bihar, different regions have different sizes of bigha. Near the capital, Patna, one bigha is equivalent to 20 katha. 1 Katha equating to 1,361 square feet (126.4 m^{2}). One katha is further subdivided in 20 dhur. Hence each dhur is approximately 68.05 square feet (6.322 m^{2}). One dhur is further subdivided in 20 dhurki, each dhurki being approximately 3.403 square feet (0.3161 m^{2}).

1 decimal in Bihar equals to 435 sq feet.

In some of eastern parts of the Bihar including Munger, Bhagalpur and Jamui, one dhur is further subdivided into one square lagga (pole length). One lagga is equivalent to 5.5 hand lengths, with each hand length being 18 inches (460 mm). Therefore one lagga is 99 inches, or 251.46 cm.

In Himachal Pradesh, five bigha is equal to one acre (0.0809 hectare).

In Punjab, four bigha is equal to one acre.

In central India, bighas were standardized at 3025 yd^{2}(2529.3 m^{2}) or 5/8 acre (0.2529 hectare).

In Madhya Pradesh, one Katha = 600 square feet (56 m^{2}).

In Rajasthan, one bigha is equal to 1,618.7 square metres (17,424 sq ft).

In Uttar Pradesh, one bigha can mean different things to people in different districts of the state. In the more developed western districts of the state one bigha is either equal to five biswa (one biswa is 125 square metres (1,350 sq ft) or 6.75 biswa. In the remainder of Uttar Pradesh, 1 bigha is divided into 20 biswas. Each biswa is 125 m^{2} or 154.32 yd^{2} (hence one Bigha is 0.25 Hectare (or 2500 m^{2} or 3086.4 yd^{2}(). 7 Biswa ~ 1 Bigha (Kaccha)

In Uttar Pradesh (West) the measurements are slightly different: one Bigha=20 20 biswa=60 Decimal=2428.80 m^{2}

In Uttarakhand, 1 Bigha is subdivided into 19 Bissas or 12 Nali. One Bigha is 968 yd^{2} or 800 m^{2}.

In West Bengal, the Bigha was standardized under British colonial rule at 1600 yd^{2} (0.1338 hectare or 0.3306 acre); this is often interpreted as being 1/3 acre (it is precisely ^{40}⁄_{121} acre). In metric units, a bigha is hence 1333 m^{2}.

Uses in Bangladesh

Bigha is a traditional unit of land in entire Bangladesh, with land purchases still being undertaken in this unit. One bigha is equal to 1,600 square yard as standardized in pre-partition Bengal during the British rule. In other words, 3 bigha are just 0.5 katha/360 sq ft short of 1 acre.

Measurements of area in terms of bigha

1 Katha (কাঠা) = 720 sq ft (66.89 sq m)
1 Bigha (বিঘা) = 20 katha (কাঠা) (14,400 sq ft or 1,337.8 sq m)
1 Acre (একর) = 3 bigha (বিঘা) 60.5 katha (কাঠা) (4,840 sq yd or 43,560 sq ft)

Use in Nepal

A Bigha is a customary unit of measurement in Nepal, equal to about 6,773 square meters. Officially, most measurement of lands use units of either Bigha (in Terai region) or Ropani (Nepali: रोपनी) (in Hilly regions). Metric system (SI unit of square metre) is very seldom used officially in measuring area of land.

Measurement of area in terms of bigha

1 Bigha (बिघा)= 20 Kattha (कठ्ठा) (about 6,772.63 m² or 72900 sq.ft.)
1 Kattha (कठ्ठा) = 20 Dhur (धुर) (about 338.63 m² or 3,645 sq.ft.)
1 Dhur (धुर) = 16.93 m² or 182.25 sq.ft.
1 Kanwa (कनवा) = 1/16 Dhur (धुर)
1 Kanaee (कनई) = 1/16 Kanwa (कनवा) [Kanwa is largely obsolete and is used only when tiny lands are very precious]
1 Bigha = 13.31 Ropani (रोपनी)
1 Ropani = 16 aana (आना) (about 508.72 m² or 5476 sq. ft.)
1 aana = 4 paisa (पैसा) (about 31.80 m² or 342.25 sq.ft.)
1 paisa = 4 daam (दाम) (7.95 m²)

1 Bigha = 6,772.63 m²

For the different Ropani system from the one above