Dial `*124#` from your BSNL number
Send an SMS with `BAL` to `123`
Use the BSNL Selfcare app to check data balance
Log in to the BSNL website and view your account balance
Call BSNL customer care at `1503` or `1800-180-1503` and ask for data balance
Check the data balance message sent by BSNL after recharge or usage updates