If the GST portal is down and your deadline is today, three things are true at once: the outage does not move the due date, the late fee is computed automatically from the day you actually file — Rs. 50 a day for a return carrying liability, Rs. 20 for a nil return, capped at Rs. 10,000 under CGST section 47 — and almost everything that takes time can be done while the site is still broken. This page is the last part: what to preserve now, how to file the minute the portal answers, and exactly what the delay costs if it does not answer in time.
Is It the Portal, or Is It You?
Worth ninety seconds before you write the day off, because three of the most common "the portal is down" failures are not the portal.
- The signing utility.DSC signing runs through a small application on your own machine, not on the portal. When it is not running, or a browser update has stopped talking to it, the failure appears at the last step of filing and looks exactly like a server error. Restarting it, or switching to EVC where the return allows it, fixes a "portal down" that was never down.
- A stale session. A session that expired mid-form throws errors on submit rather than sending you back to a login screen. Signing out completely and back in is a ten-second test.
- Your network. Try a different connection — a phone hotspot is enough. A DNS or ISP-level problem produces a total, convincing, entirely local blackout.
If it survives all three, it is the portal. On a genuine outage the failure is usually uniform — everyone in your professional group is seeing it at the same minute, and the error is a gateway or timeout message rather than something about your data.
An Outage Is Not an Extension
The due date is in the Rules. Only a notification changes it, and a notification is published — never assumed.
This is the part that costs people money, because the intuition is so reasonable: the government's own website failed, so surely the government cannot charge me for being late. Sometimes that turns out to be right. After severe outages the Board has issued notifications extending a due date or waiving late fees for the affected period. But those come afterwards, they are specific about which return and which period they cover, and until one exists the date in the Rules is the date.
So the correct posture on an outage day is to behave as though no relief is coming, and treat one as a windfall if it arrives. Every hour spent waiting for an announcement is an hour not spent on the preparation below — which is worth doing even if the portal comes back at four in the afternoon.
What to Do in the Next Hour
In order, and none of it needs the portal:
- Screenshot the failure with a visible clock. Capture the error text and the error code if one is shown. It costs nothing and it is the only evidence you control.
- Finish the numbers. Your outward supplies, your input credit, the RCM entries, the net cash position. The portal is where a return is filed; it is not where a return is worked out. On a normal day this is the part that takes the hour.
- Build the GSTR-1 JSON offline. The Returns Offline Tool prepares the file without touching the portal, so when the site returns the upload is a two-minute job rather than an evening of typing.
- Reconcile before you file, not after. Check your input credit against GSTR-2B now. A mismatch found on the portal at 11pm becomes a return you file wrong to beat a clock; the same mismatch found at 6pm is just a correction.
- Check the payment rail separately. If you already hold a valid challan, see the next section — the money can often move even when the filing cannot.
Filing the Moment It Recovers
Recovery is rarely clean. The portal usually comes back partially — the dashboard loads, then the return page times out, then the payment gateway lags behind both. Work in the order that locks in the irreversible steps first.
Pay before you file, if you owe. Cash has to be in the electronic cash ledger before it can be offset against the liability, and the payment leg depends on banks as well as on the portal. Getting the money into the ledger is the step with the most moving parts, so it is the step to clear first.
Then file, then verify. A return is filed when it is signed and the acknowledgement number comes back — not when the form submits. If the acknowledgement does not appear, the return is not filed, however finished the screen looks. Save it when it does.
When the Payment Is the Part That Broke
A challan is generated on the portal and carries a CPIN that is valid for fifteen days. That detail decides what is possible during an outage:
- If you already hold a valid challan, the payment can often go through even while the portal is unwell, because it settles through the banking system. That is the single strongest argument for generating the challan early rather than on the due date.
- If you do not hold one yet, the challan itself needs the portal, so there is nothing to pay against until it returns. Have the amount worked out and ready.
- If a payment failed, retry it against the same challan. Money debited but not yet visible in the cash ledger is usually in transit; it settles. Generating a second challan and paying that one as well converts a delay into a refund claim.
What Being Late Actually Costs
Two separate charges, computed independently, and it helps to see them as numbers rather than as a category called "penalty".
| Charge | Rate | Applies to | Ceiling |
|---|---|---|---|
| Late fee (s.47) | Rs. 50 per day (Rs. 20 for a nil return) | Every day from the due date to the filing date | Rs. 10,000 |
| Interest (s.50) | 18% per annum | The part of the liability discharged in cash, for the days delayed | None |
Two days late on a return with a Rs. 40,000 cash liability is Rs. 50 × 2 in fee and roughly Rs. 39 in interest. That is the actual shape of the thing. It is not nothing, and it is not a catastrophe — and knowing the number is what stops an outage day turning into a rushed, wrong filing.
The knock-on effects matter more than the fee. A late GSTR-1 delays your B2B clients' input credit, which is a business problem rather than a tax one. And a return left unfiled blocks the next period's, so a single missed month compounds into a sequence. The GSTR-1 guide covers what goes in which table.
If It Is 15 September and It Is Advance Tax
The income-tax portal has its own bad days, and they land on the same dates for the same reason. The consequence is different, and milder: a missed advance-tax instalment is not a default, it is interest under 234C (now s.425 of the Income-tax Act 2025) at 1% a month on the shortfall, charged for three months until the next instalment date.
On a Rs. 30,000 shortfall that is Rs. 900. Pay it the day the portal returns and it stops there. If you file under the presumptive scheme, the whole year is due in one instalment on 15 March in any case, so a September outage is not your problem at all — the advance-tax guide sets out which of the two you are, and the shortfall guide works the interest through end to end.
Work out the exact shortfall interestEnter what you have paid and what you owe; the calculator returns the instalment position and what a delay costs, to the rupee.Making the Next One a Non-Event
Outage days are not random. They cluster on the 11th, the 20th and the 15th, because that is when everyone files. The whole of the fix is to stop arriving on those dates with work still to do.
- Generate the challan early.Fifteen days of validity is fifteen days of insurance, and it is the one step that decouples your payment from the portal's health.
- Keep the figures current. If the numbers are already assembled, an outage costs you an upload rather than an evening.
- Aim for the 18th, not the 20th. Two days of slack absorbs almost every outage that has ever happened, and it costs nothing.