GSTR-1 Explained: Who Files and When

GSTR-1 is the GST return in which a business reports all its outward supplies, that is, its sales, for a period. Every regular GST-registered business files it, either monthly or quarterly (under the QRMP scheme). GSTR-1 lists your sales invoices, and this data flows to your buyers so they can claim their input tax credit. In short, GSTR-1 is your statement of "here's everything I sold and the GST I charged." Because due dates and rules can change, always confirm the current dates on the official GST portal before filing.

What GSTR-1 is for

GST works on matching: the tax you charge on a sale is the tax the buyer wants to claim as credit. GSTR-1 is how your sales get reported to the system, so the buyer's GSTR-2B (their available credit) can be built from it. If you don't file GSTR-1, or file it wrong, your customers' ITC suffers, which is why timely, accurate GSTR-1 filing matters for business relationships, not just compliance.

Who has to file GSTR-1

Every regular GST-registered taxpayer files GSTR-1, even if there were no sales in the period (then you file a "Nil" return). Some categories don't file GSTR-1, they have their own returns:

• Composition scheme taxpayers (they file CMP-08/GSTR-4 instead).
• Input Service Distributors, non-resident taxable persons, and a few others have separate returns.

For a normal shop, distributor or firm registered under the regular scheme, GSTR-1 is mandatory.

What GSTR-1 contains

GSTR-1 is organised into sections by the type of sale:

B2B sales are reported invoice by invoice (with the buyer's GSTIN), because those buyers need the detail for their ITC. B2C small sales are usually reported as rate-wise totals.

Monthly vs quarterly (QRMP)

How often you file depends on turnover and your choice:

• Monthly: larger businesses (and anyone who opts for it) file GSTR-1 every month.
• Quarterly (QRMP scheme): businesses with turnover up to a threshold (commonly ₹5 crore) can opt to file GSTR-1 quarterly, while paying tax monthly. Under QRMP, there's also an Invoice Furnishing Facility (IFF) to upload B2B invoices monthly so buyers get their credit without waiting for the quarter.

Confirm the current turnover threshold and scheme details on the GST portal, as these can change.

Due dates (verify current dates)

Due dates are set by the government and can be revised, so treat the following as the general pattern and check the portal for the exact current dates:

• Monthly GSTR-1: typically due around the 11th of the following month.
• Quarterly GSTR-1 (QRMP): typically due around the 13th of the month after the quarter.

Because these dates change and extensions happen, never rely on memory; check the official due-date calendar before each filing.

How GSTR-1 connects to other returns

Your sales → GSTR-1 → builds your buyer's GSTR-2B → their input tax credit

And separately, you summarise and pay your own tax in GSTR-3B. So GSTR-1 (detailed sales) and GSTR-3B (summary + payment) are filed for the same period and should agree with each other.

Real-world scenario (why accuracy in GSTR-1 matters)

Suppose a distributor forgets to include a ₹5,00,000 B2B invoice in GSTR-1. The customer who bought those goods won't see that invoice in their GSTR-2B, so they can't claim the ₹90,000 ITC on it. The customer complains, chases the distributor, and the relationship sours, all because of a missed entry. Multiply this across many invoices and you see why accountants reconcile their sales register with GSTR-1 before filing. In a job, "can you prepare and file GSTR-1?" is a common interview question, because it directly affects customers and cash.

How Tally helps

If you've recorded your GST sales invoices correctly in TallyPrime, the software prepares the GSTR-1 data for you, grouped into the right sections. You review it, fix any mismatches (Tally flags incomplete entries), and then file on the GST portal, either by exporting the return or using Tally's connected filing. Clean sales entries in Tally make GSTR-1 filing quick; messy entries make it painful.

Pro tips

• Reconcile your sales register with the GSTR-1 summary before filing, so nothing is missed.
• File on time; late filing attracts late fees and delays your customers' ITC.
• Even with no sales, file a Nil GSTR-1; skipping it causes compliance problems.
• Always check the current due date on the portal, since dates and extensions change.

Common mistakes

• Missing B2B invoices. These deny customers their ITC and damage relationships. Report every B2B sale invoice-wise.
• Wrong GSTIN of the buyer. A typo means the credit goes to the wrong or no one; double-check GSTINs.
• GSTR-1 and GSTR-3B not matching. The detailed sales in GSTR-1 should agree with the summary in GSTR-3B.
• Assuming a fixed due date. Dates change; verify each period on the portal.

Key takeaways

• GSTR-1 reports all your outward supplies (sales) for a period.
• Every regular GST taxpayer files it, monthly or quarterly (QRMP), even Nil.
• B2B sales are reported invoice-wise so buyers can claim ITC.
• Tally prepares GSTR-1 from your sales entries; verify due dates on the portal.

Practice task

List five sales invoices (some to registered businesses, some retail). Sort them into B2B and B2C, and note which need the buyer's GSTIN. Then look up the current GSTR-1 due date for monthly filers on the official GST portal.

Learn to prepare and file GST returns in Tally, step by step, in the ADFA program at HCI.