GSTR-1 reports the sales you made. GSTR-3B is where tax is computed, input credit is claimed, and the money actually moves. Both are required, and the figures need to agree with each other and with your books.
Due dates
GSTR-3B is due on the 20th of the following month for monthly filers.
Under the QRMP scheme, smaller taxpayers file quarterly while paying tax monthly. The quarterly GSTR-3B is due on the 22nd or the 24th of the month following the quarter, depending on which state or union territory you operate in — the states are split into two groups for this purpose.
QRMP is quarterly filing, not quarterly paying. Tax is still deposited every month. Businesses that miss this distinction accrue interest while believing they are compliant.
Late fees and interest
| Situation | Charge |
|---|---|
| GSTR-3B filed late, tax payable | Rs 50 per day of delay |
| GSTR-3B filed late, nil liability | Rs 20 per day of delay |
| Tax paid after the due date | Interest at 18% per annum on the outstanding tax |
The daily fee looks small and compounds quietly. A return three months late on a normal filing runs to roughly Rs 4,500 in late fee alone, before interest.
The three-year bar
This is the change that has caught out businesses with old arrears. A GSTR-3B cannot be filed once three years have passed from its due date. Previously, an old return was an expensive problem you could still fix. Now it can become a problem you cannot fix at all — the return simply cannot be filed, while the consequences of not having filed it remain.
If you have returns approaching that age, they should be dealt with now rather than at the next convenient moment. This is the single most time-sensitive item in GST compliance for a business with a backlog.
Why mismatches matter more than the fee
The late fee is the visible cost. The larger risk is the reconciliation. Input tax credit depends on your suppliers having filed their own returns, and credit you cannot match to a supplier’s filing is credit you may lose. Chasing a supplier three months after the fact usually works. Chasing them at assessment, two years later, usually does not.
A workable rhythm
- Send your sales and purchase data on a fixed date each month, not when you remember.
- Reconcile input credit against supplier filings monthly, while there is still time to chase.
- File nil returns for months with no activity — a nil return is still a return.
- Deal with any backlog approaching three years as a priority.