Biswa (Punjab) to Bigha (Uttar Pradesh / Bihar, Pucca): the quick answer
To convert biswa (Punjab) to bigha (Uttar Pradesh / Bihar, pucca), multiply the value by 0.04. To go the other way, multiply bigha (Uttar Pradesh / Bihar, pucca) by 25 to get biswa (Punjab).
↔ Convert bigha (Uttar Pradesh / Bihar, pucca) to biswa (Punjab) instead