GSTR-1 Explained Simply: Who Files, What Goes In, Due Dates

GSTR-1 is the return where you list your sales under GST. Every regular GST-registered business files it, monthly by the 11th or quarterly by the 13th, even when there were no sales. It carries no payment. It decides what your buyers can claim as credit and what lands in your own GSTR-3B.

What is GSTR-1, and why does it exist?

GST runs on matching. You charge tax on a sale. Your buyer wants that tax back as input tax credit (ITC), the GST on purchases that a business sets off against the GST on its sales. The government allows that credit only when the seller has reported the invoice. GSTR-1 is that report. Section 37 of the CGST Act calls it the details of outward supplies, which simply means everything you sold or billed.

So GSTR-1 is less about you and more about the people you sell to. File it late or wrong, and your registered buyers lose credit for the month. They will call you before the department does.

Who has to file it?

Every registered person under the regular scheme: traders, manufacturers, service providers, online sellers. It does not matter how small the month was.

You do not file GSTR-1 if you are a composition taxpayer, an input service distributor, a non-resident taxable person, or registered only to deduct TDS or collect TCS under GST.

Monthly or quarterly: which one are you?

If your aggregate turnover (all sales under your PAN, across India) is up to Rs 5 crore in the current and the previous year, you can choose QRMP: quarterly returns with monthly payment. Above Rs 5 crore, you file monthly.

Does quarterly filing hurt your business buyers, who want credit every month? It can. That is why the Invoice Furnishing Facility (IFF) exists. In the first two months of a quarter you may upload only your B2B invoices and credit or debit notes, by the 13th of the next month. It is optional, and reports put the limit at Rs 50 lakh of invoices a month. What you upload in the IFF is not repeated in the quarterly GSTR-1.

You pick or change the frequency on the portal under Services, Returns, Opt-in for quarterly return. For the January to March quarter, the window is 1 November to 31 January.

What goes into each table?

A small shop with only counter sales usually touches Tables 7, 12 and 13. A wholesaler lives in Table 4. If you sell on Amazon, Flipkart or Meesho, Table 14 matters too, and our separate guide on GSTR-1 for e-commerce sellers covers that case.

When is it due, and what does a delay cost?

Monthly: the 11th of the next month. Quarterly: the 13th of the month after the quarter. The late fee is Rs 50 a day (Rs 25 CGST plus Rs 25 SGST), or Rs 20 a day for a nil return. Since June 2021 it is capped per return:

There are two harder stops. You cannot file this month's GSTR-1 while an earlier one is pending. And a GSTR-1 cannot be filed at all once three years have passed from its due date.

A worked example

You run a hardware store with Rs 80 lakh turnover and file monthly. Your March GSTR-1 was due on 11 April. You file on 23 April, 12 days late.

• Late fee: 12 x Rs 50 = Rs 600. The cap for you is Rs 2,000.
• One March invoice was to a contractor: Rs 1,00,000 plus Rs 18,000 GST. The March credit statement of your buyer (GSTR-2B) is drawn up on the 14th of April. Your invoice missed it.
• The contractor gets the Rs 18,000 credit a month later and pays that much extra in cash for March.

Rs 600 is the small part. The Rs 18,000 pushed onto your customer is the real cost.

What if you had no sales?

You still file. A nil GSTR-1 takes a minute: generate the summary with no entries, submit and sign. Quarterly filers can also file nil by SMS to 14409. Skipping it costs Rs 20 a day up to Rs 500 and blocks the next return.

How do you fix a mistake?

Before filing, you can edit or delete anything. After filing, you have two routes.

• GSTR-1A, same period. An optional form that opens after you file GSTR-1 (or after its due date, whichever is later) and stays open until you file GSTR-3B for that period. You can use it once per period to add a missed invoice or correct one. The change flows into your GSTR-3B. Your buyer sees it in the next period's GSTR-2B.
• Amendment, later period. Report the corrected invoice in Table 9, or the corrected B2C total in Table 10, of a later GSTR-1.

The outer limit for both is 30 November after the end of the financial year, or the date you file the annual return, whichever is earlier. For a sale made in FY 2025-26, that is 30 November 2026.

Where do your numbers go next?

Two places. First, each B2B invoice appears in your buyer's GSTR-2B, the monthly statement of credit they may claim. Second, your totals are filled into Tables 3.1 and 3.2 of your own GSTR-3B, the return where you pay. Those auto-filled sales figures are now locked there. So a wrong GSTR-1 becomes a wrong tax payment unless you correct it through GSTR-1A first. At year end, the same figures fill your annual return. See who must file GSTR-9.

The mistake people usually make

They treat GSTR-1 as a formality because no money moves, and give all their attention to GSTR-3B. Then the sales in the two returns stop matching. A gap between GSTR-1 and GSTR-3B is the most common reason for a system-generated notice. The fix costs nothing: before filing, total your sales register and compare it with the GSTR-1 summary, table by table.

The second mistake is typing a buyer's GSTIN wrongly. The invoice then shows up for a stranger, and your real buyer gets no credit until you amend it.

Can you do this yourself? With a few dozen invoices a month, yes. The portal's own steps are in our guide to filing GSTR-1 on the portal. With hundreds of invoices, several tax rates or frequent returns, a second pair of eyes each month is cheaper than a year-end clean-up.

Frequently asked questions

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