Last updated: 14 June 2026. GSTR-3B for the May 2026 tax period is due on 20 June 2026 for monthly filers. File it on the portal by selecting the period, reviewing the liability auto-populated from your GSTR-1, confirming your eligible Input Tax Credit in Table 4, offsetting the tax against your credit and cash ledgers, and submitting with DSC or EVC. This guide walks through each step, the fields you can no longer edit, and exactly what a late return costs.
Applicability Note: This guide reflects GST provisions, CBIC notifications, and GSTN advisories applicable as of 14 June 2026. Return formats, portal behaviour, and due dates change through notifications and system updates, and the GST portal is the authoritative source. No extension to the 20 June 2026 GSTR-3B deadline has been notified as of this writing. Always verify the current position on gst.gov.in or with a GST professional before filing.
Who Should Care?
This guide applies to:
- Regular taxpayers filing GSTR-3B monthly (turnover above ₹5 crore, or anyone who opted out of QRMP) for the May 2026 period due 20 June
- QRMP taxpayers who pay May tax through PMT-06 and file GSTR-3B quarterly
- Business owners and accountants who want to file correctly the first time and avoid interest and late fees
- Anyone who has fallen behind and wants to know what a delayed GSTR-3B actually costs
1. What GSTR-3B Is and When It's Due for May 2026
GSTR-3B is the self-assessed summary return under Section 39 of the CGST Act, read with Rule 61. In one return you declare your outward tax liability, claim your eligible Input Tax Credit (ITC), set the two off against each other, and pay the balance in cash. It is not a line-by-line invoice return — that is GSTR-1 — but it is the return that actually settles the tax for the month.
One point to fix in your mind before you start: GSTR-3B cannot be revised once filed. There is no edit button after submission. Any error is corrected in a later period's return, so the few minutes spent checking before you file are the only clean chance you get.
| Filer type | Return / payment for May 2026 | Due date |
|---|---|---|
| Monthly filer (GSTR-3B) | GSTR-3B for May 2026 | 20 June 2026 |
| QRMP taxpayer | PMT-06 — tax for May (month 2 of the quarter) | 25 June 2026 |
| QRMP taxpayer | GSTR-3B for the Apr–Jun quarter | 22nd / 24th July 2026 (state-wise) |
If you are on the QRMP scheme, you do not file a GSTR-3B for May at all — you pay the month's tax through Form GST PMT-06 by 25 June and file the quarterly GSTR-3B in July. For everyone else, 20 June is the date that matters. The monthly filing sequence is simple: file your GSTR-1 first, then GSTR-3B — the portal will not let you file GSTR-3B for a period until the GSTR-1 for that period is filed.
2. What's Auto-Populated — and What's Now Locked
The portal pre-fills most of GSTR-3B for you. What you can change has narrowed, and knowing the difference is the single biggest filing change in the last year.
Outward liability (Tables 3.1 and 3.2) is now locked
Your outward tax liability in Tables 3.1 and 3.2 is auto-populated from the GSTR-1 / IFF you already filed. Since the July 2025 tax period, these auto-populated liability figures are hard-locked — non-editable in GSTR-3B, per the GSTN advisory dated 7 June 2025. You can no longer quietly type a different sales figure into GSTR-3B than the one in your GSTR-1.
How to fix a wrong sales figure now: if the liability flowing in is wrong, correct it at source by amending your GSTR-1/IFF through Form GSTR-1A for the same tax period, before you file GSTR-3B. GSTR-1A (enabled via Notification No. 12/2024-Central Tax dated 10 July 2024) updates the auto-populated figure so the locked number in GSTR-3B becomes the correct one. There is no longer a way to override it inside GSTR-3B itself.
This has been in force since July 2025, so treat it as the established way returns work — not a new change to worry about. Practically, it means your GSTR-1 has to be right before you file it, because that is now the number you are stuck with.
Input Tax Credit (Table 4) is still editable
Your ITC in Table 4 is auto-populated from your GSTR-2B, in the revised format introduced by Notification No. 14/2022-Central Tax dated 5 July 2022 and Circular No. 170/02/2022-GST dated 6 July 2022. Unlike the liability side, this figure remains editable on the portal as of June 2026. You adjust it down for reversals you have to make — blocked credits under Section 17(5), the 180-day non-payment reversal, and anything ineligible. What you should not do is claim more than your GSTR-2B supports: that is exactly what triggers a Rule 88D intimation. Run a proper GSTR-2B reconciliation before you file so Table 4 reflects matched, eligible credit.
3. Step-by-Step: Filing GSTR-3B Correctly
- File GSTR-1 first. Confirm your outward supplies are right before you file GSTR-1 — that figure now locks into GSTR-3B. If you spot an error after filing GSTR-1, fix it through GSTR-1A for the same period before moving on.
- Open GSTR-3B for May 2026. On the portal, go to Returns Dashboard → select the May 2026 period → GSTR-3B → Prepare Online.
- Review the locked liability (Tables 3.1, 3.2). Check the auto-populated outward tax. If it is wrong, stop and amend GSTR-1 via GSTR-1A — do not try to edit it here.
- Confirm ITC in Table 4. Match the auto-populated figure against your reconciled GSTR-2B and purchase register. Reduce it only for genuine reversals; keep a working that ties your claim back to GSTR-2B.
- Check Table 5 and any RCM. Report exempt, nil-rated and non-GST inward supplies, and confirm any reverse-charge tax in Table 3.1(d) is paid in cash (ITC cannot be used to pay RCM liability).
- Proceed to payment. The portal computes the balance after setting off ITC. Offset, then pay any cash shortfall.
- File with DSC or EVC. Submit the return. Once filed it is final — there is no revision, so verify the numbers before you hit file.
4. Paying the Tax: Cash Ledger, Credit Ledger and Interest
GST is paid from two ledgers. Your electronic credit ledger holds your ITC; your electronic cash ledger holds money you deposit. Under Section 49 and the order of utilisation in Sections 49A/49B read with Rule 88A, available ITC is set off against your liability first, and only the remaining balance is paid in cash. IGST credit is used first, then CGST and SGST credit against their respective heads, subject to the cross-utilisation rules.
A common trap: the cash you need must actually sit in the cash ledger before you offset. If you create the challan and pay it late on the 20th, the deposit can take time to reflect, and the return is not filed until the offset goes through. Fund the cash ledger a day early.
Interest on late payment — Section 50: if you pay your tax after the due date, interest runs at 18% per annum under Section 50(1) (rate notified by Notification No. 13/2017-Central Tax dated 28 June 2017). The relief built into the law is that, for a belated return, interest is charged only on the net tax paid through the cash ledger — not on the portion you settle using ITC. So a large ITC balance keeps your interest small. (The exception is interest on wrongly availed and utilised ITC under Section 50(3), also 18%, which is computed differently.)
5. What a Late GSTR-3B Costs: Late Fee + Interest
A late GSTR-3B carries two separate charges — interest on the tax (above) and a daily late fee for the return itself — plus a knock-on effect on your other filings.
Late fee (Section 47)
Late fee is governed by Notification No. 19/2021-Central Tax dated 1 June 2021. It accrues per day from the day after the due date until you file, and is capped by your turnover. The figures below are the total (CGST + SGST combined, split equally between the two):
| Return type / turnover (AATO, previous year) | Late fee per day | Maximum cap |
|---|---|---|
| Nil return (no liability) | ₹20/day | ₹500 |
| Up to ₹1.5 crore | ₹50/day | ₹2,000 |
| ₹1.5 crore to ₹5 crore | ₹50/day | ₹5,000 |
| Above ₹5 crore | ₹50/day | ₹10,000 |
So even a nil GSTR-3B filed late attracts ₹20 a day up to ₹500 — being nil does not make you exempt from the late fee, only from interest.
The knock-on cost: blocked filings and e-way bills
GSTR-3B filing is sequential — you cannot file a later month until the earlier one is filed, so one skipped return stalls every return after it, with late fee accruing on each. And under Rule 138E, failing to file GSTR-3B for two consecutive tax periods blocks your ability to generate e-way bills, which can bring dispatches to a halt. A return you keep postponing gets more expensive and more disruptive by the week. If a delay has already led to a notice, our guide on how to reply to a GST notice online walks through the response.
Key Takeaways
- GSTR-3B for May 2026 is due 20 June 2026 for monthly filers; QRMP taxpayers pay via PMT-06 by 25 June and file quarterly in July.
- Outward liability in Tables 3.1 and 3.2 is hard-locked from your GSTR-1 since the July 2025 tax period — fix errors through GSTR-1A before filing, not inside GSTR-3B.
- ITC in Table 4 is still editable; reduce it for reversals, but never claim above your reconciled GSTR-2B.
- GSTR-3B cannot be revised once filed — verify every figure before submission.
- Late payment carries 18% interest under Section 50, charged only on the net tax paid in cash for a belated return.
- Late filing adds a daily late fee (₹50/day, ₹20 for nil) capped at ₹500–₹10,000 by turnover, and two missed returns block e-way bill generation.
Frequently Asked Questions
What is the due date for GSTR-3B for May 2026?
For monthly filers, GSTR-3B for May 2026 is due on 20 June 2026. QRMP taxpayers do not file a monthly GSTR-3B — they pay May's tax through Form PMT-06 by 25 June and file the quarterly GSTR-3B in July. No extension has been notified as of 14 June 2026.
Can I edit the sales figure auto-populated in GSTR-3B?
No. Since the July 2025 tax period, the outward liability in Tables 3.1 and 3.2 is hard-locked from your GSTR-1/IFF. To correct it, amend your GSTR-1 through Form GSTR-1A for the same tax period before filing GSTR-3B; the corrected figure then flows into the locked field.
How much interest do I pay if I file GSTR-3B late?
Interest runs at 18% per annum under Section 50(1) on the tax paid late. For a belated return it is charged only on the net tax discharged through the cash ledger, not on the part paid using ITC, so a larger ITC balance reduces the interest.
Is there a late fee on a nil GSTR-3B?
Yes. A nil GSTR-3B filed after the due date attracts ₹20 per day (CGST + SGST combined), capped at ₹500, under Notification No. 19/2021-Central Tax dated 1 June 2021. A nil return avoids interest but not the late fee.
Can I revise GSTR-3B after filing?
No. GSTR-3B cannot be revised once filed. Any error — in liability or ITC — is corrected in a subsequent period's return, which is why the figures must be checked before submission.
Disclaimer: This article is for informational purposes only and does not constitute professional tax advice. GST rules are subject to frequent changes through notifications and circulars. Please consult a qualified tax professional or verify the current provisions on the official GST portal (gst.gov.in) before making any compliance decisions.
Have a specific question about filing GSTR-3B or fixing a return error? Our GST experts can help → gstconsultancy.com