The basic and essential difference between GSTR-1 and GSTR-3B is as follows:
Meaning: GSTR-1 is to be filed monthly or quarterly based on the assessee's turnover. The assessee has to provide all the relevant information regarding outward supplies i.e., sales or turnover. At the same time, GSTR-3B is a self-assessment return that must be filed monthly. The assessee must provide all the information regarding the purchase and sales.
Filing Date: If the annual revenue of the assessee exceeds Rs 1.5 Crores in the previous or current year, then the due date to file GSTR-1 of the current month is the 11th day of the next month. However, if the annual turnover is less than Rs 1.5 Crores, then GSTR-1 can be filed quarterly, and the due date to file quarterly returns will be the 30th or 31st day of the month after the quarter. Irrespective of the assessee's turnover, GSTR-3B has to be filed monthly, and the due dates are mentioned in the blog in detail.
Tax Payable: While filing GSTR-1, the assessee has to pay no amount of tax. Whereas in GSTR-3B, filing is completed only after paying the outstanding tax. Even in the case of no tax liability, the assessee has to file a nil return.
Penalties: A penalty of Rs 200/day is levied on the assessee for filling GSTR-1 after the due date. For nil GSTR-3B