How to File GSTR-1: Due Dates, Tables, Late Fees and Steps (2026)

Once a month or once a quarter, every regular GST-registered business tells the government what it sold. That statement is GSTR-1. For a shop owner it is often the most stressful part of GST, not because the form is long, but because it asks for numbers that were never kept in one place: every bill, every buyer's GSTIN, every HSN code, every cancelled invoice.

This guide explains how to file GSTR-1 in 2026: who files it and when, which tables a small shop actually needs (most need only four or five of the fifteen), what the late fee is, how to file a nil return, what GSTR-1A is for, and the exact steps on the GST portal. It ends with a month-end routine that turns filing from an evening's work into a few minutes.

What is GSTR-1?

GSTR-1 is a statement of every taxable supply you made in a tax period: what you sold, to whom, at what value and with how much tax. It does not pay any tax. Tax is paid through GSTR-3B, the summary return filed after it.

GSTR-1 still matters more than its "statement only" label suggests, for two reasons:

1. It feeds your buyers' input tax credit. When you report a B2B invoice in GSTR-1, it appears in your buyer's GSTR-2B, which is what they use to claim credit. A late or wrong GSTR-1 holds up their credit, and they will call you about it.
2. It is checked against GSTR-3B. The tax you declare in GSTR-1 should match the tax you pay in GSTR-3B for the same period. Large gaps trigger notices.

The portal also expects GSTR-1 to be filed before GSTR-3B for the same period. A missed GSTR-1 holds up the rest of your month's compliance.

Who has to file GSTR-1

Every person registered as a normal taxpayer files GSTR-1, including those with no sales in the period, who file a nil return.

These registrations do not file GSTR-1:

• Composition dealers, who file CMP-08 every quarter and GSTR-4 once a year. See our guide to the GST composition scheme.
• Input service distributors, non-resident taxable persons, persons deducting TDS or collecting TCS, and suppliers of online information services from outside India. Each has its own return.

GSTR-1 due dates in 2026

You file either monthly or quarterly. Quarterly filing is available under the QRMP scheme (Quarterly Return Monthly Payment) to businesses with aggregate turnover up to ₹5 crore in the previous financial year.

For a quarterly filer, the GSTR-1 dates for the four quarters fall on 13 July, 13 October, 13 January and 13 April. When the government extends a date, it does so by notification and the portal shows the revised date on the Returns Dashboard, so check there before you assume a deadline.

What IFF is for

The Invoice Furnishing Facility (IFF) exists because of a QRMP filer's B2B buyers. If you file quarterly, your buyers would otherwise wait up to three months to see your invoices in their GSTR-2B. IFF lets you upload just the B2B invoices of the first and second months of the quarter, so your buyers can claim credit monthly.

IFF is optional. If you sell only to consumers, you can ignore it and file one GSTR-1 a quarter. If you have regular B2B customers, they will usually ask you to use it.

GSTR-1 tables: the four most small shops need

The GSTR-1 form has a long list of tables, which is why it looks frightening. Most kirana, retail and small trading businesses touch only a handful of them.

So in practice, a typical shop's GSTR-1 is Table 7 + Table 12 + Table 13, with Table 4 added for business customers and Table 9 for credit notes. Everything else is usually blank.

Table 4: B2B invoices

Every invoice to a registered buyer goes here individually: the buyer's GSTIN, invoice number and date, invoice value, place of supply, taxable value by rate, and the tax. A wrong GSTIN is the most common error in GSTR-1. It sends the credit to the wrong business, or nowhere, and your buyer cannot claim it until you amend it.

Whether the tax is CGST and SGST or IGST depends on the place of supply. Our guide to the difference between CGST, SGST and IGST explains how to tell.

Table 5: B2C Large

This table covers inter-state sales to unregistered buyers where the invoice value is above ₹1 lakh. The threshold was ₹2.5 lakh until it was lowered to ₹1 lakh in 2024, and many guides still quote the old figure. Intra-state consumer sales never go here, however large; they go in Table 7.

Table 7: B2C Small

All other consumer sales are reported as totals, not invoice by invoice: taxable value and tax, grouped by place of supply and GST rate. For a shop that sells over the counter, this is where most of the month's turnover lands.

Table 12: HSN summary

Table 12 groups your sales by HSN code, with the unit (UQC), total quantity, taxable value and tax for each. If your previous-year turnover was up to ₹5 crore, report at least 4 digits; above ₹5 crore, at least 6 digits.

From the April 2025 return period, the portal splits Table 12 into separate B2B and B2C tabs, and HSN codes are chosen from a drop-down list rather than typed freely. A missing or invalid code now stops you at validation. Our guide to HSN codes explains how to find the right code for each item.

Table 13: Documents issued

Here you report the serial number ranges of invoices, credit notes and other documents issued in the period, the total count, and how many were cancelled. If your invoices run from SLS-1001 to SLS-1180 and two were cancelled, that is what this table says. Gaps in numbering with no cancellations recorded are what draw questions.

Table 9: amendments, credit and debit notes

Credit notes (for returns or reductions after the bill was issued) and debit notes go in Table 9B, split between registered and unregistered buyers. Corrections to invoices reported in an earlier period, such as a wrong GSTIN or a wrong value, are made through the amendment tables, not by editing the old return.

How to file GSTR-1 on the GST portal, step by step

1. Log in at gst.gov.in with your username and password.
2. Go to Services → Returns → Returns Dashboard.
3. Choose the financial year and the return filing period (the month, or the quarter for QRMP filers), then click Search.
4. On the GSTR-1 tile, click Prepare Online. If you have a JSON file from your billing software or the GST offline tool, use Prepare Offline to upload it instead.
5. Fill the tables that apply to you: open each tile, add the invoices or totals, and Save. The portal saves each table separately, so you can stop and come back.
6. Click Generate GSTR-1 Summary. The portal totals everything you entered. Allow a minute for it to refresh.
7. Click Preview to download the draft as a PDF. Check the totals against your sales register and against what you plan to declare in GSTR-3B.
8. Tick the declaration and select the authorised signatory.
9. Click File Statement and sign with EVC (an OTP sent to the registered mobile number) or DSC (digital signature). DSC is mandatory for companies and LLPs; proprietors and partnerships usually use EVC.
10. Download the acknowledgement (ARN) for your records.

Once filed, a GSTR-1 cannot be edited. Corrections go through amendment tables in a later period, or through GSTR-1A, explained below.

Filing a nil GSTR-1

If you made no outward supplies in the period, you still file. On the GSTR-1 tile, tick File Nil GSTR-1, then file with EVC or DSC. A nil GSTR-1 can also be filed by SMS from the registered mobile number. A nil return is quick, but it is not optional; skipping it attracts the nil late fee.

GSTR-1 late fee

The late fee is charged per day of delay, and it is capped per return based on your turnover.

The fee is the smaller cost. The bigger ones are your buyers' delayed credit, and the fact that you cannot file GSTR-3B for the period until GSTR-1 is in.

The three-year limit

Under changes made by the Finance Act 2023, a return cannot be filed after three years from its due date, and the GST portal began enforcing this in 2025. A very old GSTR-1 that was never filed may simply not be fileable any more, which leaves the gap permanently on your record. File every period, even a nil one, on time.

GSTR-1A: fixing a GSTR-1 you have already filed

GSTR-1A, available since July 2024, is an optional form that lets you amend or add details for the same tax period after you file GSTR-1 but before you file GSTR-3B for that period. If you notice a missed invoice or a wrong GSTIN the day after filing GSTR-1, GSTR-1A lets you correct it in the same month, rather than carrying the error into the next period's amendment tables.

Once GSTR-3B for the period is filed, the GSTR-1A window for that period closes, and corrections go through the regular amendment tables.

Before you file: a pre-filing checklist

Run through this before you open the portal:

• Every invoice for the period is in your sales register, and the numbering has no unexplained gaps.
• Cancelled invoices are marked as cancelled, not deleted.
• Each B2B buyer's GSTIN has been checked (on the portal's search taxpayer page, or by your billing app's format check).
• Each B2B invoice has the right place of supply, and so the right split between CGST + SGST and IGST.
• Every item line carries an HSN code with enough digits for your turnover.
• Credit notes for returns and discounts after billing are recorded.
• Your totals by rate match what you will pay in GSTR-3B.

A month-end routine that makes GSTR-1 easy

Most of the effort in GSTR-1 is not on the portal; it is finding and cleaning the data. A short routine at the end of each month removes most of it:

1. Close the books on the 1st. On the first day of the month, stop editing last month's bills. Corrections from now on are credit or debit notes.
2. Export the month. Take the sales summary from your billing software: taxable value and tax by rate, B2B invoices with GSTINs, HSN summary, and the invoice number range.
3. Reconcile with cash and bank. Compare total sales with what came into the drawer, the UPI account and the bank. A big gap usually means a bill that was never made, or one made twice.
4. Send it to your CA, or file it yourself, well before the 11th or 13th. Filing on the last day is when the portal is slowest.
5. Keep the ARN. Save the acknowledgement with the month's export, so every return has its evidence next to it.

If your bills are made in software that records the HSN code, rate and GSTIN with every invoice, steps 2 and 3 take minutes. If they are handwritten, this is the month to change that. Our guide to the GST invoice format lists what every bill has to show.

Common GSTR-1 mistakes

• Reporting a B2B sale as B2C. If the buyer gave you a GSTIN, the invoice belongs in Table 4. Lumping it into Table 7 costs the buyer their credit.
• A wrong or mistyped GSTIN. The credit goes nowhere. Validate GSTINs when you add a customer, not at month-end.
• Wrong place of supply. CGST + SGST charged on an inter-state sale, or IGST on a local one. The tax was paid to the wrong government and needs correcting.
• Using the old B2C Large threshold. Inter-state consumer invoices above ₹1 lakh go in Table 5, not only those above ₹2.5 lakh.
• Table 12 not matching the rest of the return. The HSN totals should add up to the same value and tax as the other tables.
• Missing Table 13. It is easy to forget, and it is where missing invoice numbers show.
• Wrong rates after September 2025. From 22 September 2025, most goods moved to 5% or 18%, with 40% for luxury and sin goods. An item list set up earlier may still carry 12% or 28%. Our guide on how to calculate GST has the current slabs.

How BillZap helps with GSTR-1

BillZap is a free GST billing app for Android. It works offline and needs no sign-up. It does not file returns on the GST portal for you; filing is still done by you or your CA. What it does is make sure the data GSTR-1 asks for is already there, and correct, when the month ends:

• Every bill is numbered in sequence, so Table 13 is a range, not a search.
• Each item carries its HSN code and GST rate, so every line has them and Table 12 is consistent.
• CGST + SGST or IGST is worked out from the place of supply on every bill.
• Customer GSTINs are saved once with the customer, not typed again at month-end.
• The GST reports export gives a GSTR-1 ready JSON plus CSV files with month-wise taxable value, CGST, SGST and IGST, which you or your CA can use when filing.

If you are still deciding on software, our review of GST billing apps compares how each one handles returns.

FAQ: filing GSTR-1

The bottom line

Filing GSTR-1 is mostly about having the right data before you open the portal: every invoice numbered, every B2B buyer's GSTIN correct, every item carrying an HSN code and the current rate. With that in place, a small shop's return comes down to Table 7, Table 12, Table 13 and perhaps Table 4, and the filing itself takes minutes. Without it, the same return can take an evening and still go in with errors.

The easiest fix is upstream, at the counter. If you want a free app that numbers every bill, keeps HSN codes and GSTINs with the items and customers, and exports a GSTR-1 ready summary at month-end, BillZap is on Google Play. It works offline with no sign-up.

This guide explains GSTR-1 filing in plain language and is not tax advice. Due dates, fees and portal rules change by notification; confirm the current position with your chartered accountant or the GST portal before you file.