How to File GSTR-1: Complete Table-Wise Guide

If you are registered under GST, learning how to file GSTR-1 properly protects both you and your customers. GSTR-1 is the statement of outward supplies: every sale, export, credit note and advance you report here flows into your buyers' GSTR-2B and becomes the basis on which they claim input tax credit. A missing or wrong entry in your GSTR-1 can block your customer's credit, delay your payment and invite a mismatch notice for you. This guide covers each table, the difference between monthly and quarterly filing, how amendments work and the checks to run before filing.

Who files GSTR-1 and when

Every normal taxpayer files GSTR-1, including those with no sales in a period (a nil GSTR-1). Composition taxpayers do not file GSTR-1. There are two options:

Filer type	Frequency	Usual due date
Monthly filer	Every month	11th of the following month
QRMP filer (turnover up to ₹5 crore, opted in)	Every quarter	13th of the month after the quarter
QRMP filer using IFF	Optional, for months 1 and 2 of a quarter	1st to 13th of the following month

The Invoice Furnishing Facility (IFF) lets quarterly filers upload B2B invoices monthly so that their customers get credit without waiting for the quarter end. Due dates can be extended by notification, so confirm on the portal.

The main tables of GSTR-1 explained

Table 4: B2B supplies

All supplies to registered persons, invoice by invoice, with GSTIN, invoice number, date, value, place of supply, rate and tax. Supplies attracting reverse charge are flagged here too. If you issue e-invoices, these records are auto-populated from the Invoice Registration Portal (IRP), but you should still review them.

Table 5: B2C large (B2CL)

Inter-state supplies to unregistered persons where the invoice value exceeds the prescribed limit. The limit was reduced from ₹2.5 lakh to ₹1 lakh in 2024; check the current figure on the portal. These are reported invoice-wise.

Table 6: Exports and SEZ supplies

Exports with or without payment of IGST, and supplies to SEZ units or developers. Shipping bill details are added for goods once available.

Table 7: B2C small (B2CS)

All other supplies to unregistered persons: intra-state supplies of any value and inter-state supplies below the B2CL limit. These are reported in summary by place of supply and rate, not invoice-wise.

Table 8: Nil-rated, exempt and non-GST supplies

Summary values, split into inter-state and intra-state, registered and unregistered.

Table 9: Amendments and credit or debit notes

Table 9A for amendments to earlier invoices, and Table 9B for credit and debit notes issued to registered persons (CDNR) and unregistered persons (CDNUR).

Table 11: Advances

Advances received for services on which tax is payable, and adjustments of earlier advances against invoices. For goods, advances are generally not taxable on receipt.

Table 12: HSN-wise summary

Summary by HSN or SAC code. Businesses with aggregate turnover up to ₹5 crore report at least 4-digit codes and those above ₹5 crore report 6-digit codes. The portal now separates B2B and B2C summaries and uses a drop-down list of valid codes, which means a wrong code in your item master will surface here. Our guide on finding the right HSN and SAC code helps you fix the master.

Table 13: Documents issued

Serial number ranges of invoices, credit notes, debit notes, delivery challans and other documents issued, with cancelled counts.

Tables 14 and 15: E-commerce supplies

Supplies made through e-commerce operators, including those where the operator pays tax under section 9(5).

How to file GSTR-1 on the portal: step by step

1. Log in to the GST portal and go to Services, Returns, Returns Dashboard.
2. Select the financial year and period and open GSTR-1 (or IFF).
3. Choose to prepare online for small volumes, or use the offline tool or a JSON file exported from your accounting software for larger volumes.
4. Fill or upload each table. Review auto-populated e-invoice data in Table 4, 6 and 9B.
5. Fill the HSN summary in Table 12 and the document summary in Table 13.
6. Click Generate GSTR-1 Summary and compare the summary totals with your sales register.
7. Click Preview, download the draft and review it once more.
8. File with DSC or EVC. Note the ARN and download the filed copy.

Worked example: classifying a month's invoices

A Delhi-based distributor issued these invoices in a month. All goods are taxed at 18%.

Invoice	Customer	Taxable value	Tax	GSTR-1 table
INV-101	Registered buyer in Delhi	₹2,00,000	CGST ₹18,000 + SGST ₹18,000	Table 4 (B2B)
INV-102	Registered buyer in Haryana	₹3,00,000	IGST ₹54,000	Table 4 (B2B)
INV-103	Unregistered buyer in Punjab	₹1,50,000	IGST ₹27,000	Table 5 (B2CL), since invoice value exceeds ₹1 lakh
INV-104	Unregistered buyer in Uttar Pradesh	₹40,000	IGST ₹7,200	Table 7 (B2CS), below the B2CL limit
INV-105	Walk-in customers in Delhi (summary)	₹80,000	CGST ₹7,200 + SGST ₹7,200	Table 7 (B2CS)
CN-07	Credit note to Haryana buyer for returned goods	₹50,000	IGST ₹9,000	Table 9B (CDNR)

Total taxable value of invoices is ₹7,70,000 and the credit note reduces it by ₹50,000, giving net outward taxable value of ₹7,20,000. Total tax on invoices is ₹36,000 + ₹54,000 + ₹27,000 + ₹7,200 + ₹14,400 = ₹1,38,600, and after the credit note of ₹9,000, net tax is ₹1,29,600. This net figure is what should flow into Table 3.1(a) of GSTR-3B. Note that 18% of ₹7,20,000 is also ₹1,29,600, which is a quick sanity check.

GSTR-1A: correcting before GSTR-3B

GSTR-1A is an optional facility that lets you add missed invoices or amend details reported in GSTR-1 for the same period, after filing GSTR-1 but before filing GSTR-3B for that period. Corrections made in GSTR-1A flow into your GSTR-3B liability and into your buyers' GSTR-2B for a later period. It is useful when a buyer rejects an invoice in the Invoice Management System or when you discover an error after filing GSTR-1. For buyers' side actions, read our IMS guide.

Time limits and the three-year bar

GSTR-1 for a period cannot be filed if the previous period is pending, so a single missed month blocks everything after it. Amendments to invoices of a financial year are allowed only up to 30 November of the following year or the date of filing the annual return, whichever is earlier. The law also bars filing returns after three years from their due date, and the portal has begun enforcing this time bar. Check the latest advisory if you have very old pending returns.

Common GSTR-1 mistakes

• Wrong GSTIN of buyer. The credit lands in someone else's GSTR-2B. Validate GSTINs in your customer master.
• Wrong place of supply. Charging CGST and SGST on an inter-state supply means the buyer cannot use the credit and you must pay IGST and claim a refund of the wrong tax.
• Reporting B2B supplies as B2C. Your customer loses credit and will ask you to amend.
• Not reporting credit notes, which overstates your liability.
• HSN summary not matching invoices because the item master has outdated codes.
• Skipping nil returns, which blocks later returns and accrues late fees.

Pre-filing checklist for GSTR-1

1. All invoices, credit notes and debit notes for the period are posted.
2. Cancelled invoices are marked cancelled, not deleted.
3. Buyer GSTINs are validated and states match the place of supply.
4. E-invoice data from the IRP is reconciled with the books.
5. HSN summary totals equal the invoice totals.
6. Document summary ranges are continuous and gaps are explained.
7. Summary totals match the sales register before filing.

A monthly GSTR-1 routine that works

Teams that file GSTR-1 without stress usually follow the same small routine every month. It spreads the work across the month instead of piling it into the two days before the 11th.

1. Weekly: review new customer masters for valid GSTINs and correct state codes, and check that every invoice has an HSN or SAC code.
2. By the 3rd of the next month: confirm all invoices, credit notes and debit notes for the closed month are posted, and that cancelled documents are marked cancelled.
3. By the 5th: reconcile IRP data (if you issue e-invoices) with the sales register. Any invoice in the books but missing on the IRP, or the reverse, needs attention before filing.
4. By the 7th: generate the GSTR-1 data, review the B2CL and B2CS split and the HSN summary, and share large customers' invoice lists with them if they ask.
5. By the 9th: file GSTR-1, leaving two days of buffer for portal slowness on the due date.
6. After filing: watch for rejections by buyers in the Invoice Management System and plan GSTR-1A corrections before GSTR-3B.

This routine also improves your customer relationships. Buyers increasingly check GSTR-2B before paying, and a supplier who reports invoices early and correctly gets paid without follow-up calls.

How Fininvo helps with GSTR-1

Fininvo ERP prepares GSTR-1 data directly from your posted invoices and credit notes, with HSN and SAC codes mapped on each item, and exports it in the government-prescribed JSON format. When e-invoicing is enabled, IRN data is available alongside the invoice. Explore GST invoicing, tax compliance and pricing.

General information only, not tax advice. Thresholds and due dates change by notification; please consult your CA.

Frequently Asked Questions

Is GSTR-1 required if I have no sales?

Yes. A nil GSTR-1 must be filed for each period while your registration is active. It can be filed online or through SMS.

What is the difference between GSTR-1 and GSTR-3B?

GSTR-1 reports invoice-level details of outward supplies and feeds your buyers' GSTR-2B. GSTR-3B is the summary return where you declare liability, claim ITC and pay tax. Both must agree; persistent differences can lead to intimations.

How do I report a credit note in GSTR-1?

Report it in Table 9B: CDNR if issued to a registered person and CDNUR if issued to an unregistered person for an inter-state B2CL invoice. Credit notes against B2CS supplies are adjusted in the B2CS summary.

Can I amend an invoice reported in a previous GSTR-1?

Yes, through Table 9A of a later GSTR-1, or through GSTR-1A for the same period before filing GSTR-3B. Amendments for a financial year are allowed until 30 November of the next year or the annual return date, whichever is earlier.

Do e-invoices still need to be reported in GSTR-1?

E-invoice details are auto-populated into GSTR-1, so you do not upload them again, but you must review them, add any non-e-invoice supplies such as B2C sales, and file the return yourself.