GST Return Filing — documents, process and timeline

GST return filing is the recurring obligation that follows registration. Two returns carry most of the work: GSTR-1, which reports what you sold, and GSTR-3B, which summarises the period and pays the tax. Monthly filers file GSTR-1 by the 11th and GSTR-3B by the 20th; QRMP filers file both quarterly but still pay monthly.

The filing itself is mechanical. What separates a return that is merely submitted from one that is correct is the reconciliation against GSTR-2B — the auto-drafted statement of input credit that your suppliers have actually reported. Since section 16(2)(aa) took effect, credit is available only where the supplier has declared the invoice. Claim credit that is not in 2B and it is reversed with interest at 18% a year when the department matches, which it now does automatically.

That reconciliation is also the most useful thing a filing engagement produces, because it tells you which supplier has not filed while there is still time to withhold payment and chase them. Discovering it a year later, in the annual return, means the credit is usually gone.

There is a hard deadline on claiming credit at all: input credit for a financial year must be claimed by 30 November following it, or the date of the annual return, whichever is earlier. After that it is simply lost, and no amount of reconciliation recovers it.

We prepare both returns from your books rather than from a summary you type, reconcile against 2B before filing, file before the statutory date, and put the acknowledgement in your portal. Where the numbers disagree with your accounts, you hear about it before the return goes rather than after.

A second category of error is credit that should never have been claimed at all. Section 17(5) blocks input credit on a defined list regardless of whether the supplier reported it — motor vehicles with under thirteen seats, food and beverages, outdoor catering, club and gym memberships, health insurance except where a statute requires you to provide it, works contract services for immovable property, and goods lost, stolen, destroyed or given away as samples. Claiming blocked credit is not a timing difference that corrects itself; it is a reversal with interest whenever the department looks, and it is one of the first things a scrutiny officer tests.

The third thing worth building into the monthly rhythm is the reverse charge check. On a defined set of supplies the liability sits with the recipient rather than the supplier — goods transport agency services, legal services from an advocate, sponsorship, director sitting fees, and imports of service among them. The tax has to be paid in cash rather than set off against existing credit, and only then can the corresponding credit be claimed. Businesses that miss reverse charge accumulate a liability quietly for years, and it surfaces in an audit with interest attached.

Rule 86B is the fourth trap, and it catches growing businesses specifically. Where taxable turnover exceeds ₹50 lakh in a month, at least 1% of the output liability must be discharged in cash even if you hold enough input credit to cover all of it. There are exemptions — for taxpayers who have paid more than ₹1 lakh in income tax in each of the last two years, and for exporters who have received a refund above ₹1 lakh — but a business that crosses the threshold without knowing the rule files a return the portal simply refuses to accept, usually on the due date.

Finally, the reconciliation is worth doing even in months where nothing looks wrong. The commonest pattern we see on taking over a client is not fraud or carelessness but drift: a supplier who quietly stopped filing eighteen months ago, credit claimed against their invoices every month since, and a liability that has compounded at 18% without anybody noticing. Monthly matching catches that in the first cycle. Annual matching catches it when the credit is already time-barred and the money is gone.

It is worth being clear about what the filing rhythm actually costs in attention rather than fees. GSTR-1 fixes what your customers can claim, so an invoice reported late or wrongly becomes their problem and then your phone call. GSTR-3B fixes what you pay. The two must agree with each other and with your books, and the reconciliation against 2B has to happen between the 14th, when 2B is generated, and the 20th, when payment is due. That is a six-day window every month in which the work has to be done properly, and it is why businesses that treat GST filing as a month-end afterthought accumulate problems that businesses treating it as a mid-month routine do not.

Who needs it

Every registered taxpayerThe obligation attaches to the registration, not to the trading. A GSTIN that made no supplies at all still files a nil return, and still attracts a late fee if it does not.
Monthly filers above ₹5 croreAggregate turnover above ₹5 crore means monthly GSTR-1 and GSTR-3B, with no quarterly option.
QRMP filers below ₹5 croreQuarterly returns with monthly payment in PMT-06 by the 25th. It reduces the filing count, not the payment schedule.
Composition dealersCMP-08 quarterly by the 18th and the annual GSTR-4 by 30 April, rather than GSTR-1 and 3B.
E-commerce operatorsGSTR-8 monthly for tax collected at source, in addition to their own returns as a supplier.

Which one applies to you

Monthly filerGSTR-1 by the 11th and GSTR-3B by the 20th, every month. The default above ₹5 crore turnover.
QRMPAvailable below ₹5 crore. GSTR-1 and 3B quarterly, but tax still paid monthly by the 25th in PMT-06.
CompositionCMP-08 quarterly by the 18th, and the annual GSTR-4 by 30 April.
Nil filerA registered person with no supplies still files. It can be done by SMS, and not doing it still attracts the late fee.

Why it is worth doing

Your input credit actually landsReconciling against 2B before filing is what stops credit being claimed and then reversed with interest a year later. It is the whole economic value of doing this properly.
Supplier defaults surface in timeThe mismatch report names the supplier who has not filed, in the month it happens, while you still hold their payment as leverage.
Notices become rareMost GST notices are automated mismatches between GSTR-1, 3B and 2B. Returns prepared together and reconciled before filing do not generate them.
Your registration stays activeContinued non-filing blocks GSTR-1, then e-way bill generation, and can end in cancellation of the registration — which stops the business, not just the filing.

What is included

GSTR-1 outward supplies, monthly or quarterly
GSTR-3B summary return and tax computation
GSTR-2B input credit reconciliation with a supplier mismatch report
Filing acknowledgement in your portal

What we need from you

Sales register or invoice data for the period
Purchase register with supplier GSTINs
Debit and credit notes issued
Details of exports, if any, and the LUT

How it works

Data collectionSales and purchase registers for the period, with debit and credit notes. We pull them from your accounting system where you have one.
GSTR-2B reconciliationYour purchase register is matched against the credit your suppliers actually reported. Mismatches are listed with the supplier named, while there is still time to chase them.
GSTR-1 preparationOutward supplies invoice by invoice for B2B, consolidated for B2C, with exports and credit notes.
GSTR-3B and paymentThe summary return with the tax computed after eligible credit, and the challan generated for what is payable.
Filing and acknowledgementBoth filed before the statutory date, with the acknowledgement in your portal rather than in an email you have to search for.

Monthly filing or QRMP?

	Monthly	QRMP
Eligibility	Any turnover; compulsory above ₹5 crore	Turnover up to ₹5 crore
GSTR-1	By the 11th, every month	Quarterly, by the 13th
GSTR-3B	By the 20th, every month	Quarterly, by the 22nd or 24th
Tax payment	Monthly with the return	Still monthly, in PMT-06 by the 25th
Credit to your buyer	Appears in their 2B monthly	Monthly only if you use IFF
Best for	Anyone with B2B customers who want prompt credit	Small filers with mostly B2C sales

What affects the timeline

When your books closeWe can only reconcile what has been recorded. A sales register that arrives on the 9th makes an 11th deadline tight; one that arrives on the 3rd does not.
How many suppliers have filedGSTR-2B is generated on the 14th. Suppliers who file late do not appear in it, and chasing them is what turns a two-hour reconciliation into a two-day one.
Volume and channel mixA few dozen B2B invoices reconcile quickly. Thousands of marketplace transactions across multiple states need the data pulled and normalised first.
Amendments and credit notesCorrections to earlier periods have to be carried into the current return in the right place, and each one is a manual decision rather than an import.

What happens afterwards

The acknowledgement lands in your portalARN and filed return for each period, downloadable rather than requested by email.
A supplier mismatch reportNamed suppliers who have not reported invoices you hold, with amounts, while there is still leverage to chase them.
Annual return preparationGSTR-9 above ₹2 crore turnover and GSTR-9C above ₹5 crore, both by 31 December, built from the year's filings.
The November credit cut-off trackedInput credit for the year must be claimed by 30 November following it. We flag anything unclaimed before that date rather than after.

What usually goes wrong

Claiming credit that is not in GSTR-2BSince section 16(2)(aa), credit is available only where the supplier has reported it. Claim it anyway and it is reversed with interest at 18% when the department matches.
Filing 3B without reconciling 1A difference between the two is an automated notice. They should be prepared together and agree before either is filed.
Missing the credit deadlineInput credit for a financial year must be claimed by 30 November following it, or the deadline for the annual return, whichever is earlier. After that it is simply lost.
Not filing a nil returnThe obligation does not pause because you had no sales. The late fee accrues on a nil return exactly as it does on any other.

Questions

What is the late fee for a GST return?

₹50 a day — ₹25 CGST and ₹25 SGST — capped per return, and ₹20 a day for a nil return. Interest runs at 18% a year on unpaid tax. The bigger cost is usually blocked input credit and a stalled e-way bill facility, not the fee itself.

What is QRMP and should I be on it?

Quarterly Return Monthly Payment, for taxpayers under ₹5 crore turnover. You file GSTR-3B quarterly but still pay monthly. It cuts the filing load. The catch is that your B2B customers only see their credit quarterly unless you also use the Invoice Furnishing Facility each month.

Do I have to file if I had no sales?

Yes. A nil return is still a return, and the ₹20 a day late fee applies to it. Nil GSTR-1 and GSTR-3B can be filed by SMS, so there is no practical excuse for missing one.

What is GSTR-2B and why does it matter?

An auto-drafted, static statement of the input credit your suppliers have reported for the period. Since 2022 your credit is limited to what appears in it — so 2B, not your purchase register, decides what you can actually claim.

Can a GST return be revised?

No. There is no revised return in GST. A mistake is corrected in a later period's return, and only up to 30 November following the financial year. After that the error stands.

What happens if I stop filing?

Two consecutive months of non-filing blocks GSTR-1 and e-way bill generation, which stops you moving goods. Six months triggers a cancellation notice in REG-17. Restoring it means filing every overdue return with its late fee, paying the tax and interest, and then applying for revocation in REG-21 — several times the cost of having filed.

Who has to file GSTR-9 and GSTR-9C?

GSTR-9, the annual return, is compulsory above ₹2 crore aggregate turnover and optional below it. GSTR-9C, the reconciliation between the annual return and the audited accounts, is required above ₹5 crore. Both are due by 31 December and neither can be revised once filed.

What is the Invoice Furnishing Facility?

An optional monthly upload for QRMP filers, letting you report B2B invoices in the first two months of a quarter so your customers see their input credit monthly rather than waiting for the quarterly GSTR-1. If you have B2B customers and are on QRMP, you generally should use it.

Can I claim input credit on everything I buy?

No. Section 17(5) blocks credit on a defined list — motor vehicles below thirteen seats, food and beverages, club memberships, health insurance except where statutorily required, works contract for immovable property, and goods lost, stolen or given as free samples. Claiming blocked credit is a common and expensive error.