GSTR-1 & GSTR-3B Filing (2026): Due Dates, Late Fees, the Hard-Lock & the New 3-Year Bar

File faster with a GSTR-1-ready summary

Clean GSTR-1 is now the whole game — it sets your locked GSTR-3B liability. GST Bill Maker keeps every invoice correctly taxed and gives you a GSTR-1-ready summary, so your outward-supply figures are right before they lock. Browse the Knowledge Center for more filing and compliance guides.

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

Q: What’s the difference between the 22nd and 24th GSTR-3B due date under QRMP? A: It depends on the state of your principal place of business — states are split into two groups for staggered filing.

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

Q: I have a GSTR-3B pending from three years ago. Can I file it? A: If more than three years have passed since its due date, no — the portal permanently bars it. File any pending returns before they cross the three-year mark.

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

Q: Can I still change the tax figure in GSTR-3B if I made a mistake in GSTR-1? A: Not directly. Since July 2025 the liability is locked. Correct it in GSTR-1A before filing that period’s GSTR-3B.

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

Frequently asked questions

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

Frequently asked questions

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

From the July 2025 tax period, the portal will not permit filing of any return more than three years after its due date — GSTR-1, 3B, 4, 5, 5A, 6, 7, 8 and 9 are all covered. Old, forgotten periods can no longer be regularised once the three years pass; the liability crystallises and the return window closes for good. If you have any pending historic returns, file them now — the clock is running on each one from its original due date.

Common mistakes to avoid

Editing GSTR-3B to differ from GSTR-1 — no longer possible; fix GSTR-1 via GSTR-1A first.
Filing GSTR-1 late — it now directly delays your 3B liability and can block future GSTR-1.
Ignoring the 18% interest — a late fee is small; interest on unpaid tax is not.
Sitting on old unfiled returns — the three-year bar makes them permanently un-fileable.
Missing the QRMP monthly PMT-06 — quarterly returns still need monthly tax deposits.
Not filing nil returns — a zero-sales month still needs a return, or the late fee accrues.

Frequently asked questions

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

The three-year permanent bar

Common mistakes to avoid

Editing GSTR-3B to differ from GSTR-1 — no longer possible; fix GSTR-1 via GSTR-1A first.
Filing GSTR-1 late — it now directly delays your 3B liability and can block future GSTR-1.
Ignoring the 18% interest — a late fee is small; interest on unpaid tax is not.
Sitting on old unfiled returns — the three-year bar makes them permanently un-fileable.
Missing the QRMP monthly PMT-06 — quarterly returns still need monthly tax deposits.
Not filing nil returns — a zero-sales month still needs a return, or the late fee accrues.

Frequently asked questions

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

This is phase one. The government has signalled that ITC (Table 4) hard-locking is targeted for around July 2026, which will tie your claimable credit to GSTR-2B just as tightly — another reason to keep your ITC reconciliation clean.

The three-year permanent bar

Common mistakes to avoid

Editing GSTR-3B to differ from GSTR-1 — no longer possible; fix GSTR-1 via GSTR-1A first.
Filing GSTR-1 late — it now directly delays your 3B liability and can block future GSTR-1.
Ignoring the 18% interest — a late fee is small; interest on unpaid tax is not.
Sitting on old unfiled returns — the three-year bar makes them permanently un-fileable.
Missing the QRMP monthly PMT-06 — quarterly returns still need monthly tax deposits.
Not filing nil returns — a zero-sales month still needs a return, or the late fee accrues.

Frequently asked questions

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

The practical consequence: get GSTR-1 right, because that is your 3B liability now. If you spot an error after filing GSTR-1, correct it through GSTR-1A before you file that period’s GSTR-3B — that’s the only way to change the locked figure. Table 3.2 (inter-state supplies to unregistered and composition persons) is locked the same way.

The three-year permanent bar

Common mistakes to avoid

Editing GSTR-3B to differ from GSTR-1 — no longer possible; fix GSTR-1 via GSTR-1A first.
Filing GSTR-1 late — it now directly delays your 3B liability and can block future GSTR-1.
Ignoring the 18% interest — a late fee is small; interest on unpaid tax is not.
Sitting on old unfiled returns — the three-year bar makes them permanently un-fileable.
Missing the QRMP monthly PMT-06 — quarterly returns still need monthly tax deposits.
Not filing nil returns — a zero-sales month still needs a return, or the late fee accrues.

Frequently asked questions

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

Historically, taxpayers could type a different figure into GSTR-3B than what they’d reported in GSTR-1 — a gap that invited mismatch notices. From the July 2025 tax period (GSTN Advisory 606, 7 June 2025), the liability fields in GSTR-3B (Tables 3.1 and 3.2) are auto-populated from GSTR-1/IFF and locked. You can no longer edit them directly.

The three-year permanent bar

Common mistakes to avoid

Editing GSTR-3B to differ from GSTR-1 — no longer possible; fix GSTR-1 via GSTR-1A first.
Filing GSTR-1 late — it now directly delays your 3B liability and can block future GSTR-1.
Ignoring the 18% interest — a late fee is small; interest on unpaid tax is not.
Sitting on old unfiled returns — the three-year bar makes them permanently un-fileable.
Missing the QRMP monthly PMT-06 — quarterly returns still need monthly tax deposits.
Not filing nil returns — a zero-sales month still needs a return, or the late fee accrues.

Frequently asked questions

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

The 2025 game-changer: hard-locked GSTR-3B

The three-year permanent bar

Common mistakes to avoid

Editing GSTR-3B to differ from GSTR-1 — no longer possible; fix GSTR-1 via GSTR-1A first.
Filing GSTR-1 late — it now directly delays your 3B liability and can block future GSTR-1.
Ignoring the 18% interest — a late fee is small; interest on unpaid tax is not.
Sitting on old unfiled returns — the three-year bar makes them permanently un-fileable.
Missing the QRMP monthly PMT-06 — quarterly returns still need monthly tax deposits.
Not filing nil returns — a zero-sales month still needs a return, or the late fee accrues.

Frequently asked questions

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

Interest bites hardest because it runs on the tax amount, not a flat fee. On ₹2,00,000 of tax paid 30 days late, that’s roughly ₹2,959 of interest on top of the late fee — for a single month’s delay. Miss enough returns and the portal also blocks your GSTR-1 until the pending GSTR-3B is filed, freezing your ability to bill compliantly.

The 2025 game-changer: hard-locked GSTR-3B

The three-year permanent bar

Common mistakes to avoid

Editing GSTR-3B to differ from GSTR-1 — no longer possible; fix GSTR-1 via GSTR-1A first.
Filing GSTR-1 late — it now directly delays your 3B liability and can block future GSTR-1.
Ignoring the 18% interest — a late fee is small; interest on unpaid tax is not.
Sitting on old unfiled returns — the three-year bar makes them permanently un-fileable.
Missing the QRMP monthly PMT-06 — quarterly returns still need monthly tax deposits.
Not filing nil returns — a zero-sales month still needs a return, or the late fee accrues.

Frequently asked questions

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

The 2025 game-changer: hard-locked GSTR-3B

The three-year permanent bar

Common mistakes to avoid

Editing GSTR-3B to differ from GSTR-1 — no longer possible; fix GSTR-1 via GSTR-1A first.
Filing GSTR-1 late — it now directly delays your 3B liability and can block future GSTR-1.
Ignoring the 18% interest — a late fee is small; interest on unpaid tax is not.
Sitting on old unfiled returns — the three-year bar makes them permanently un-fileable.
Missing the QRMP monthly PMT-06 — quarterly returns still need monthly tax deposits.
Not filing nil returns — a zero-sales month still needs a return, or the late fee accrues.

Frequently asked questions

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

Late fees and interest — the real cost of slipping

Two separate charges stack up when you file late:

Late fee: ₹50 per day (₹25 CGST + ₹25 SGST) for a return with tax, or ₹20 per day for a nil return, subject to a cap linked to turnover.
Interest: 18% per annum on the tax paid late, calculated from the due date to the date of actual payment.

The 2025 game-changer: hard-locked GSTR-3B

The three-year permanent bar

Common mistakes to avoid

Editing GSTR-3B to differ from GSTR-1 — no longer possible; fix GSTR-1 via GSTR-1A first.
Filing GSTR-1 late — it now directly delays your 3B liability and can block future GSTR-1.
Ignoring the 18% interest — a late fee is small; interest on unpaid tax is not.
Sitting on old unfiled returns — the three-year bar makes them permanently un-fileable.
Missing the QRMP monthly PMT-06 — quarterly returns still need monthly tax deposits.
Not filing nil returns — a zero-sales month still needs a return, or the late fee accrues.

Frequently asked questions

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

QRMP (Quarterly Return, Monthly Payment) is open to businesses with turnover up to ₹5 crore. You file GSTR-1 and GSTR-3B once a quarter but still deposit tax every month through PMT-06, so cash flow to the government stays monthly. The 22nd/24th split depends on the state of your principal place of business.

Late fees and interest — the real cost of slipping

Two separate charges stack up when you file late:

Late fee: ₹50 per day (₹25 CGST + ₹25 SGST) for a return with tax, or ₹20 per day for a nil return, subject to a cap linked to turnover.
Interest: 18% per annum on the tax paid late, calculated from the due date to the date of actual payment.

The 2025 game-changer: hard-locked GSTR-3B

The three-year permanent bar

Common mistakes to avoid

Editing GSTR-3B to differ from GSTR-1 — no longer possible; fix GSTR-1 via GSTR-1A first.
Filing GSTR-1 late — it now directly delays your 3B liability and can block future GSTR-1.
Ignoring the 18% interest — a late fee is small; interest on unpaid tax is not.
Sitting on old unfiled returns — the three-year bar makes them permanently un-fileable.
Missing the QRMP monthly PMT-06 — quarterly returns still need monthly tax deposits.
Not filing nil returns — a zero-sales month still needs a return, or the late fee accrues.

Frequently asked questions

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

Return	What it covers	Monthly due date	QRMP due date
GSTR-1	Outward supplies (sales)	11th of next month	13th of month after quarter (IFF optional monthly)
GSTR-3B	Summary + tax payment	20th of next month	22nd or 24th of month after quarter (by state)
PMT-06	Monthly tax deposit (QRMP only)	—	25th of each of the first two months

Late fees and interest — the real cost of slipping

Two separate charges stack up when you file late:

Late fee: ₹50 per day (₹25 CGST + ₹25 SGST) for a return with tax, or ₹20 per day for a nil return, subject to a cap linked to turnover.
Interest: 18% per annum on the tax paid late, calculated from the due date to the date of actual payment.

The 2025 game-changer: hard-locked GSTR-3B

The three-year permanent bar

Common mistakes to avoid

Editing GSTR-3B to differ from GSTR-1 — no longer possible; fix GSTR-1 via GSTR-1A first.
Filing GSTR-1 late — it now directly delays your 3B liability and can block future GSTR-1.
Ignoring the 18% interest — a late fee is small; interest on unpaid tax is not.
Sitting on old unfiled returns — the three-year bar makes them permanently un-fileable.
Missing the QRMP monthly PMT-06 — quarterly returns still need monthly tax deposits.
Not filing nil returns — a zero-sales month still needs a return, or the late fee accrues.

Frequently asked questions

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

The monthly and quarterly calendar

Return	What it covers	Monthly due date	QRMP due date
GSTR-1	Outward supplies (sales)	11th of next month	13th of month after quarter (IFF optional monthly)
GSTR-3B	Summary + tax payment	20th of next month	22nd or 24th of month after quarter (by state)
PMT-06	Monthly tax deposit (QRMP only)	—	25th of each of the first two months

Late fees and interest — the real cost of slipping

Two separate charges stack up when you file late:

Late fee: ₹50 per day (₹25 CGST + ₹25 SGST) for a return with tax, or ₹20 per day for a nil return, subject to a cap linked to turnover.
Interest: 18% per annum on the tax paid late, calculated from the due date to the date of actual payment.

The 2025 game-changer: hard-locked GSTR-3B

The three-year permanent bar

Common mistakes to avoid

Editing GSTR-3B to differ from GSTR-1 — no longer possible; fix GSTR-1 via GSTR-1A first.
Filing GSTR-1 late — it now directly delays your 3B liability and can block future GSTR-1.
Ignoring the 18% interest — a late fee is small; interest on unpaid tax is not.
Sitting on old unfiled returns — the three-year bar makes them permanently un-fileable.
Missing the QRMP monthly PMT-06 — quarterly returns still need monthly tax deposits.
Not filing nil returns — a zero-sales month still needs a return, or the late fee accrues.

Frequently asked questions

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

The monthly and quarterly calendar

Return	What it covers	Monthly due date	QRMP due date
GSTR-1	Outward supplies (sales)	11th of next month	13th of month after quarter (IFF optional monthly)
GSTR-3B	Summary + tax payment	20th of next month	22nd or 24th of month after quarter (by state)
PMT-06	Monthly tax deposit (QRMP only)	—	25th of each of the first two months

Late fees and interest — the real cost of slipping

Two separate charges stack up when you file late:

Late fee: ₹50 per day (₹25 CGST + ₹25 SGST) for a return with tax, or ₹20 per day for a nil return, subject to a cap linked to turnover.
Interest: 18% per annum on the tax paid late, calculated from the due date to the date of actual payment.

The 2025 game-changer: hard-locked GSTR-3B

The three-year permanent bar

Common mistakes to avoid

Editing GSTR-3B to differ from GSTR-1 — no longer possible; fix GSTR-1 via GSTR-1A first.
Filing GSTR-1 late — it now directly delays your 3B liability and can block future GSTR-1.
Ignoring the 18% interest — a late fee is small; interest on unpaid tax is not.
Sitting on old unfiled returns — the three-year bar makes them permanently un-fileable.
Missing the QRMP monthly PMT-06 — quarterly returns still need monthly tax deposits.
Not filing nil returns — a zero-sales month still needs a return, or the late fee accrues.

Frequently asked questions

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

Every registered business runs the same monthly loop: report your sales in GSTR-1, then pay tax and file the summary in GSTR-3B. It sounds routine — but 2025 brought two changes that make sloppy filing expensive. GSTR-3B is now hard-locked to your GSTR-1, so you can no longer quietly edit the tax figure, and there’s a new three-year permanent bar after which old returns can never be filed. This guide covers the due-date calendar, late-fee and interest maths, the QRMP option, and the new locking rules — so you file right the first time. Position as of FY 2026-27.

At a glance

GSTR-1 (sales) is due the 11th; GSTR-3B (summary + payment) the 20th, for monthly filers.
QRMP filers (turnover up to ₹5 crore) file quarterly — GSTR-3B by the 22nd or 24th depending on state — but pay monthly via PMT-06.
Late fee ₹50/day (₹20/day for nil) plus 18% p.a. interest on tax paid late.
From July 2025, GSTR-3B liability is auto-locked from GSTR-1 — fix errors in GSTR-1A before you file 3B, not inside 3B.
New three-year cut-off: any GST return not filed within 3 years of its due date is barred forever.

The monthly and quarterly calendar

Return	What it covers	Monthly due date	QRMP due date
GSTR-1	Outward supplies (sales)	11th of next month	13th of month after quarter (IFF optional monthly)
GSTR-3B	Summary + tax payment	20th of next month	22nd or 24th of month after quarter (by state)
PMT-06	Monthly tax deposit (QRMP only)	—	25th of each of the first two months

Late fees and interest — the real cost of slipping

Two separate charges stack up when you file late:

Late fee: ₹50 per day (₹25 CGST + ₹25 SGST) for a return with tax, or ₹20 per day for a nil return, subject to a cap linked to turnover.
Interest: 18% per annum on the tax paid late, calculated from the due date to the date of actual payment.

The 2025 game-changer: hard-locked GSTR-3B

The three-year permanent bar

Common mistakes to avoid

Editing GSTR-3B to differ from GSTR-1 — no longer possible; fix GSTR-1 via GSTR-1A first.
Filing GSTR-1 late — it now directly delays your 3B liability and can block future GSTR-1.
Ignoring the 18% interest — a late fee is small; interest on unpaid tax is not.
Sitting on old unfiled returns — the three-year bar makes them permanently un-fileable.
Missing the QRMP monthly PMT-06 — quarterly returns still need monthly tax deposits.
Not filing nil returns — a zero-sales month still needs a return, or the late fee accrues.

Frequently asked questions

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

At a glance

GSTR-1 (sales) is due the 11th; GSTR-3B (summary + payment) the 20th, for monthly filers.
QRMP filers (turnover up to ₹5 crore) file quarterly — GSTR-3B by the 22nd or 24th depending on state — but pay monthly via PMT-06.
Late fee ₹50/day (₹20/day for nil) plus 18% p.a. interest on tax paid late.
From July 2025, GSTR-3B liability is auto-locked from GSTR-1 — fix errors in GSTR-1A before you file 3B, not inside 3B.
New three-year cut-off: any GST return not filed within 3 years of its due date is barred forever.

The monthly and quarterly calendar

Return	What it covers	Monthly due date	QRMP due date
GSTR-1	Outward supplies (sales)	11th of next month	13th of month after quarter (IFF optional monthly)
GSTR-3B	Summary + tax payment	20th of next month	22nd or 24th of month after quarter (by state)
PMT-06	Monthly tax deposit (QRMP only)	—	25th of each of the first two months

Late fees and interest — the real cost of slipping

Two separate charges stack up when you file late:

Late fee: ₹50 per day (₹25 CGST + ₹25 SGST) for a return with tax, or ₹20 per day for a nil return, subject to a cap linked to turnover.
Interest: 18% per annum on the tax paid late, calculated from the due date to the date of actual payment.

The 2025 game-changer: hard-locked GSTR-3B

The three-year permanent bar

Common mistakes to avoid

Editing GSTR-3B to differ from GSTR-1 — no longer possible; fix GSTR-1 via GSTR-1A first.
Filing GSTR-1 late — it now directly delays your 3B liability and can block future GSTR-1.
Ignoring the 18% interest — a late fee is small; interest on unpaid tax is not.
Sitting on old unfiled returns — the three-year bar makes them permanently un-fileable.
Missing the QRMP monthly PMT-06 — quarterly returns still need monthly tax deposits.
Not filing nil returns — a zero-sales month still needs a return, or the late fee accrues.

Frequently asked questions

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.

File faster with a GSTR-1-ready summary

At a glance

GSTR-1 (sales) is due the 11th; GSTR-3B (summary + payment) the 20th, for monthly filers.
QRMP filers (turnover up to ₹5 crore) file quarterly — GSTR-3B by the 22nd or 24th depending on state — but pay monthly via PMT-06.
Late fee ₹50/day (₹20/day for nil) plus 18% p.a. interest on tax paid late.
From July 2025, GSTR-3B liability is auto-locked from GSTR-1 — fix errors in GSTR-1A before you file 3B, not inside 3B.
New three-year cut-off: any GST return not filed within 3 years of its due date is barred forever.

The monthly and quarterly calendar

Return	What it covers	Monthly due date	QRMP due date
GSTR-1	Outward supplies (sales)	11th of next month	13th of month after quarter (IFF optional monthly)
GSTR-3B	Summary + tax payment	20th of next month	22nd or 24th of month after quarter (by state)
PMT-06	Monthly tax deposit (QRMP only)	—	25th of each of the first two months

Late fees and interest — the real cost of slipping

Two separate charges stack up when you file late:

Late fee: ₹50 per day (₹25 CGST + ₹25 SGST) for a return with tax, or ₹20 per day for a nil return, subject to a cap linked to turnover.
Interest: 18% per annum on the tax paid late, calculated from the due date to the date of actual payment.

The 2025 game-changer: hard-locked GSTR-3B

The three-year permanent bar

Common mistakes to avoid

Editing GSTR-3B to differ from GSTR-1 — no longer possible; fix GSTR-1 via GSTR-1A first.
Filing GSTR-1 late — it now directly delays your 3B liability and can block future GSTR-1.
Ignoring the 18% interest — a late fee is small; interest on unpaid tax is not.
Sitting on old unfiled returns — the three-year bar makes them permanently un-fileable.
Missing the QRMP monthly PMT-06 — quarterly returns still need monthly tax deposits.
Not filing nil returns — a zero-sales month still needs a return, or the late fee accrues.

Frequently asked questions

Q: Do I pay tax monthly under QRMP even though I file quarterly? A: Yes. Deposit tax for the first two months of each quarter via PMT-06 by the 25th; the quarterly GSTR-3B settles the balance.

Q: How much is the interest on late GST payment? A: 18% per annum on the tax paid late, from the due date to the actual payment date — separate from the daily late fee.