Ask the seller for the area in square feet or square metres as recorded in the revenue record (the 7/12 extract, jamabandi, khatauni or your state's equivalent).
Treat the biswa figure as a label, not a measurement, and compare plots per square foot.
Once you have the area in square feet, convert it to any other unit with the area unit converter.
Common questions
How many square feet in 1 biswa?
There is no single answer: a biswa differs by state and often by district. Ask for the area in square feet or square metres as recorded in the revenue record instead of converting a biswa figure.
Which states use the biswa?
Land records or local usage in Punjab, Haryana, Himachal Pradesh, Delhi, Uttar Pradesh, Uttarakhand and Rajasthan use the biswa, each with its own local size.
Why does the site not convert biswa?
Any single figure would be wrong somewhere. A rate or area in biswa cannot be compared across a district boundary; one in square feet can.
Which units are the same everywhere?
Square feet, square metres, square yards (gaj), acres, hectares, kanal and marla, guntha, cents and decimals, grounds and ares have one fixed size, and convert the same way in every state.