Rai (Thailand) to Bigha (Uttar Pradesh / Bihar, Pucca): the quick answer
To convert rai (Thailand) to bigha (Uttar Pradesh / Bihar, pucca), multiply the value by 0.63259. To go the other way, multiply bigha (Uttar Pradesh / Bihar, pucca) by 1.5808 to get rai (Thailand).
↔ Convert bigha (Uttar Pradesh / Bihar, pucca) to rai (Thailand) instead