A traditional unit that never got standardized
The bigha is a pre-metric land unit used across North and East India, the Nepal Terai, and Bangladesh. Unlike the acre — fixed at 43,560 sq ft everywhere — the bigha was defined locally, usually as a square number of local gaj (yards) or kattha, and each princely state, revenue district, and settlement survey settled on its own figure. British-era surveys recorded these local values instead of replacing them, and post-independence land records inherited them.
The practical consequence: a "5 bigha" plot can mean anything from about 0.8 acre in Uttarakhand to about 8.4 acres in the Nepal Terai. Any bigha conversion must start by asking which bigha. Our converter uses the Assam/West Bengal figure (14,400 sq ft) for India and the standard Terai figure (72,900 sq ft) for Nepal, the two most commonly requested conventions.
How the bigha divides
Sub-units follow the same regional logic. In much of North India, 1 bigha = 20 biswa, and each biswa = 20 biswansi. In Bengal, 1 bigha = 20 kattha (cottah) of 720 sq ft each, and 1 kattha = 16 chatak. In the Nepal Terai, 1 bigha = 20 kattha of 3,645 sq ft, each split into 20 dhur — see the kattha conversion page for that system in detail.
The pucca (full-size) versus kachha (smaller, often 2/3 or less) bigha distinction in Rajasthan, Punjab, and parts of UP adds another layer: the same village may historically have used both, with the kachha bigha for poorer land. Modern records normally use the pucca figure, but old family documents may not say which was meant.
Converting bigha safely
Once the local size is known, every conversion is a single multiplication through square feet. For the 1,600 gaj bigha: multiply bigha by 14,400 to get square feet, divide by 43,560 for acres, or divide by 107,639 for hectares. For any other state, substitute that state's figure from the table below. When a legal or financial decision rides on the number, verify the local definition with the district revenue office — published state figures are conventions, and a few districts deviate even from their own state's common value.