GSTR-1 | GSTR-3B | Monthly & Quarterly Filing
Invoice Verification. ITC Reconciliation. GSTR-2A/2B Matching. Starting at ₹499/month ComplianceBharo professional fee for end-to-end assistance. Government/statutory fees are charged separately at actuals.
GST return filing is the recurring reporting cycle every GST-registered business enters once its GSTIN is issued. It requires reporting sales, purchases, and tax liability to the government on a periodic basis — monthly by default, or quarterly for eligible taxpayers under the QRMP scheme — and it's a separate obligation from registration itself, continuing for as long as the GSTIN stays active.
Two returns anchor the entire cycle: GSTR-1, which reports outward supplies (sales) invoice by invoice, and GSTR-3B, the summary return where tax is actually computed and paid. Every regular taxpayer files both, in that order, every period — GSTR-1 first to declare what was sold, then GSTR-3B to settle what's owed after accounting for available Input Tax Credit.
What makes this cycle matter beyond the filer's own compliance is the ripple effect: a business's GSTR-1 feeds directly into its buyers' GSTR-2B, the statement that now determines how much ITC those buyers are allowed to claim. A late or inaccurate GSTR-1 doesn't just risk the filer's own penalty — it can genuinely block a buyer's credit for that period.
| Parameter | Details |
|---|---|
| Governing Provisions | Sections 37, 39, 44 and 52 of the CGST Act, 2017, read with the corresponding CGST Rules |
| What It Is | Periodic reporting of outward supplies, inward supplies, tax liability, and Input Tax Credit by every GST-registered person |
| Primary Returns | GSTR-1 (outward supplies) and GSTR-3B (summary return with tax payment) — the two returns every regular taxpayer files without exception |
| Filing Frequency | Monthly by default; quarterly for eligible taxpayers who opt into the QRMP scheme (turnover up to ₹5 crore) |
| Filing Platform | The GST portal (gst.gov.in), using either the online return utility or offline tools for larger data volumes |
| Downstream Impact | A correctly filed GSTR-1 determines the buyer's GSTR-2B — the auto-generated statement that is now the basis for how much Input Tax Credit they can actually claim |
Which returns apply depends on the scheme a taxpayer is registered under and their turnover — here are the six that come up most often.
| Return | Description | Frequency | Due Date |
|---|---|---|---|
| GSTR-1 | Statement of outward supplies (sales), reported invoice-wise | Monthly / Quarterly (QRMP) | 11th of the following month (monthly) / 13th of the month following the quarter (QRMP) |
| GSTR-3B | Self-assessed summary return reporting total supplies, ITC claimed, and tax paid | Monthly / Quarterly (QRMP) | 20th of the following month (monthly) / 22nd–24th of the month following the quarter, by state group (QRMP) |
| GSTR-4 | Annual return for Composition scheme dealers | Annually | 30 April following the end of the financial year |
| CMP-08 | Quarterly statement of self-assessed tax for Composition dealers | Quarterly | 18th of the month following the quarter |
| GSTR-9 | Annual return consolidating the year's GSTR-1 and GSTR-3B filings | Annually | 31 December following the end of the financial year |
| GSTR-9C | Self-certified reconciliation statement, mandatory above ₹5 crore turnover | Annually | 31 December following the end of the financial year |
The Quarterly Return Monthly Payment (QRMP) scheme is available to registered persons with aggregate turnover up to ₹5 crore in the preceding financial year. It lets them file GSTR-1 and GSTR-3B once every quarter instead of every month, cutting the core return-filing workload to a quarter of the monthly cycle.
Tax payment, however, doesn't wait for the quarter to end — QRMP taxpayers still pay tax every month using Form PMT-06, either as a fixed sum based on the previous quarter's liability or through self-assessment of the current month's actual position, keeping government cash flow steady without requiring a full monthly return.
For buyers who need their ITC sooner than the quarterly GSTR-1 would allow, QRMP suppliers can optionally use the Invoice Furnishing Facility (IFF) to upload B2B invoices for the first two months of the quarter (M1 and M2), due by the 13th of the following month — this lets those invoices show up in the buyer's GSTR-2B without waiting for the quarter's main GSTR-1.
These two returns are often confused since they're filed for the same period, but they capture entirely different information and serve entirely different purposes.
| Parameter | GSTR-1 | GSTR-3B |
|---|---|---|
| Purpose | Reports outward supplies (sales), invoice by invoice | Summary return reporting total outward/inward supplies and self-assessed tax liability |
| Invoice Details | Invoice-wise or document-wise detail is required for most categories | Only consolidated summary figures — no invoice-level detail |
| Tax Payment | No tax is actually paid through this return | Tax is paid or adjusted against available ITC through this return |
| ITC Claim | Feeds the buyer's GSTR-2B, which determines their ITC eligibility | ITC is claimed and offset against output tax liability here |
| Amendment Ability | Errors can be corrected through an amendment in a later month's or quarter's GSTR-1 | A filed GSTR-3B cannot be revised; corrections flow through adjustments in a later period's return |
| Due Date | 11th (monthly) / 13th (quarterly) | 20th (monthly) / 22nd–24th (quarterly) |
A single wrong digit in the buyer's GSTIN means the invoice never shows up correctly in that buyer's GSTR-2B, breaking their Input Tax Credit claim even though the seller reported the sale in good faith. The fix runs through Table 9A of a later GSTR-1 — amending the original invoice to correct the GSTIN, after which the corrected version flows into the buyer's next GSTR-2B.
The department's system automatically cross-checks the outward supply value declared in GSTR-1 against the summary figures reported in GSTR-3B for the same period. A material, unexplained gap between the two is one of the most common triggers for scrutiny under Section 61, which can escalate into a formal notice asking the taxpayer to reconcile and explain the difference.
Most B2C sales can be reported as a consolidated state-wise summary, but inter-state B2C invoices above ₹2.5 lakh must be reported invoice-wise in Table 5 of GSTR-1. Businesses that treat every B2C sale as eligible for consolidated reporting frequently miss this threshold, understating their invoice-wise disclosure without realising it.
Pull the auto-generated GSTR-2B for the period from the GST portal, alongside the internal purchase register maintained for the same period.
Compare each purchase invoice in the register against the corresponding entry in GSTR-2B — invoice number, taxable value, and tax amount all need to line up.
Where an invoice appears in the purchase register but not in GSTR-2B, the usual cause is that the vendor hasn't yet filed their own GSTR-1 — this needs a direct follow-up with the vendor rather than simply waiting.
ITC can only be claimed to the extent it actually appears in GSTR-2B for the period — credit for invoices still missing has to wait until the vendor reports them in a subsequent filing.
Even where an invoice correctly appears in GSTR-2B, certain categories — such as specified motor vehicle expenses, employee-related benefits, and other blocked credits — still cannot be claimed and must be identified and reversed.
Gather sales invoices, purchase invoices, credit/debit notes, and bank statements for the period, along with any advances received or RCM transactions that need separate reporting.
Check every sales and purchase invoice for accuracy — correct GSTIN, HSN/SAC codes, tax rate, and invoice numbering — since errors caught here are far cheaper to fix than errors caught after filing.
Match the purchase register against GSTR-2B, follow up on missing invoices, and identify any ineligible credit that needs to be reversed before the return is prepared.
Populate GSTR-1 with invoice-wise outward supply data and GSTR-3B with the consolidated summary, computed tax liability, and eligible ITC for the period.
Review the prepared return against the underlying books for consistency, and get sign-off from the authorised signatory before it goes anywhere near the portal.
Submit the return on the GST portal, complete payment where tax is due, and retain the ARN (Application Reference Number) generated as confirmation that the filing went through.
What's needed splits cleanly along the same line as the two core returns — sales-side documents for GSTR-1, purchase-side documents for GSTR-3B.
Different return categories run on different clocks — here's the monthly cycle and the quarterly/annual cycle side by side.
| Return | Due Date |
|---|---|
| GSTR-1 | 11th of the following month |
| GSTR-3B | 20th of the following month |
| GSTR-5 (Non-resident taxable person) | 13th of the following month |
| GSTR-6 (Input Service Distributor) | 13th of the following month |
| GSTR-7 (TDS deductor) | 10th of the following month |
| GSTR-8 (E-commerce operator, TCS) | 10th of the following month |
| Return | Due Date |
|---|---|
| QRMP GSTR-1 | 13th of the month following the quarter |
| QRMP GSTR-3B | 22nd–24th of the month following the quarter, depending on state group |
| IFF (Invoice Furnishing Facility, optional for M1/M2) | 13th of the following month |
| CMP-08 (Composition dealers) | 18th of the month following the quarter |
| GSTR-9 (Annual return) | 31 December following the end of the financial year |
| GSTR-9C (Reconciliation statement, turnover above ₹5 crore) | 31 December following the end of the financial year |
Missing these deadlines carries more than a simple late fee. Late filing attracts ₹50/day (₹25 CGST + ₹25 SGST), reduced to ₹20/day for NIL returns, plus 18% per annum interest on any unpaid tax. Under Rule 37A, a buyer's ITC can get blocked if their supplier fails to file — the buyer must reverse the credit if the supplier hasn't filed by 30 September following the financial year. E-way bill generation is blocked under Rule 138E after 2 consecutive tax periods of non-filing, and prolonged non-filing carries the risk of suo moto cancellation of registration under Section 29(2).
File GSTR-1 by the 11th and GSTR-3B by the 20th every month, or opt into the QRMP scheme for quarterly filing if turnover is up to ₹5 crore. Once turnover crosses ₹2 crore in a financial year, GSTR-9 becomes a mandatory annual filing on top of the regular monthly/quarterly cycle.
Pay tax at a fixed, concessional rate on turnover rather than on a per-transaction basis, file the quarterly CMP-08 statement, and consolidate the year in an annual GSTR-4. Input Tax Credit is not available to composition dealers under any circumstance, a trade-off for the simplified compliance cycle.
Operators required to collect tax under Section 52 withhold 1% TCS on the net value of taxable supplies made through their platform by other sellers, and report this collection through the monthly GSTR-8.
Exports are treated as zero-rated supply under Section 16 of the IGST Act, giving exporters a choice — file under a Letter of Undertaking (LUT) and export without paying IGST, later claiming a refund of accumulated ITC, or pay IGST upfront and claim it back as a refund. Either way, export invoices are reported separately in Table 6A of GSTR-1.
An ISD receives invoices for services used across multiple branches or units and distributes the eligible Input Tax Credit proportionally among them, reporting this distribution through the monthly GSTR-6.
Correctly computed, on-time filings sidestep the daily late fee, the 18% annual interest on unpaid tax, and the compliance risk that builds up with every missed deadline.
Disciplined GSTR-2B reconciliation catches every eligible credit before the filing deadline, rather than leaving it stranded because a vendor's invoice was never followed up on.
Handing off invoice verification, reconciliation, and return preparation frees up the time a business would otherwise spend cross-checking spreadsheets against the GST portal every month.
A second, professional review of invoice-level data catches GSTIN errors, rate mismatches, and threshold-based reporting requirements before they turn into a GSTR-1/GSTR-3B mismatch notice.
A consistent, on-time filing history keeps the GSTIN in good standing — a factor the department, and often lenders, look at when assessing a business's overall reliability.
Regularly filed GST returns double as a verifiable record of business turnover, which banks and NBFCs commonly rely on when evaluating loan and credit-line applications.
Have questions about GST return filing for your business? Let our experts help you figure out the right filing schedule.
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