1. What is GSTR-1?
GSTR-1 is your monthly or quarterly return of outward supplies — a record of all the sales invoices, credit notes, and debit notes you have issued during the period. When you file GSTR-1, you are reporting to the GST Network (GSTN) what you have sold, to whom, and how much GST you have collected.
This is the foundational document in the GST system. When your registered business buyer receives your invoice and claims Input Tax Credit (ITC), they are claiming credit for the GST you have reported in your GSTR-1. If your GSTR-1 is incorrect, delayed, or missing — your buyer's ITC claim can fail. This creates a downstream compliance problem that can damage your business relationships.
GSTR-1 is a reporting return — you are not paying tax when you file it. Tax payment happens separately through GSTR-3B. But accurate GSTR-1 data is what makes GST compliance clean for your entire chain of buyers.
Key point: GSTR-1 reports what you invoiced. GSTR-3B is where you calculate and pay the actual tax liability. Both must be filed every month (or quarter, under QRMP). GSTR-1 always comes first.
2. Who Must File GSTR-1?
All regular GST-registered taxpayers must file GSTR-1. This includes:
- Manufacturers and fabricators selling goods
- Wholesale traders and distributors
- Service providers registered under GST
- Importers and exporters
- E-commerce operators and sellers on platforms
Who is exempt from GSTR-1:
- Composition dealers (they file GSTR-4 instead)
- Input Service Distributors (they file GSTR-6)
- Non-resident taxable persons
- Businesses whose registration is suspended
Monthly vs Quarterly filing — the QRMP scheme
Since January 2021, businesses with annual aggregate turnover below ₹5 Crore can choose the Quarterly Return Monthly Payment (QRMP) scheme. Under QRMP:
- GSTR-1 is filed quarterly (due on the 13th of the month following the quarter)
- Tax is paid monthly through a simplified challan (PMT-06)
- Invoices for the first two months of the quarter can be uploaded using the Invoice Furnishing Facility (IFF) — optional, but recommended if your buyers need early ITC
Businesses with turnover above ₹5 Crore must file GSTR-1 monthly, due by the 11th of the following month.
| Turnover | Filing frequency | Due date | Scheme |
|---|---|---|---|
| Above ₹5 Crore | Monthly | 11th of next month | Regular |
| Up to ₹5 Crore | Quarterly | 13th of month after quarter | QRMP (optional) |
| Up to ₹5 Crore | Monthly (if not on QRMP) | 11th of next month | Regular |
3. What Goes Into GSTR-1
GSTR-1 is organized into tables. Each table covers a different type of supply. You do not need to worry about all of them every month — most businesses only actively fill 3–4 tables regularly.
Table 4 — B2B invoices (taxable)
All invoices issued to GST-registered buyers (businesses with a GSTIN). These must be reported invoice by invoice, with the buyer's GSTIN, invoice number, date, taxable value, and the CGST/SGST/IGST split. This is the most important table — it is what your buyers use to claim ITC.
Table 5 — B2C large invoices (interstate, above ₹2.5 Lakh)
Interstate invoices to unregistered buyers (consumers) where the invoice value exceeds ₹2.5 Lakh. These are reported invoice-by-invoice, even though the buyer has no GSTIN. For intrastate B2C and interstate B2C below ₹2.5 Lakh, use the consolidated table.
Table 7 — B2C small invoices (consolidated)
All other B2C invoices — intrastate sales to consumers and small-value interstate sales — reported as a single consolidated figure per state per tax rate. No individual invoice details needed.
Table 12 — HSN summary
A mandatory summary of all outward supplies organized by HSN (Harmonized System of Nomenclature) code. From April 2021, HSN codes are mandatory for all registered taxpayers: 4-digit HSN for turnover up to ₹5 Crore, 6-digit for above ₹5 Crore.
Table 9 — Credit notes and debit notes
Any credit notes (for returned goods, price reductions, or corrections) and debit notes issued during the period. Credit notes issued to GST-registered buyers must be reported invoice-by-invoice to allow the buyer to reduce their ITC accordingly.
Advances received (Table 11)
For service providers: advances received for services must be reported, with GST payable on receipt. Note for goods suppliers: GST Notification 66/2017 exempts registered manufacturers and traders from paying GST on advance receipts for goods. GST triggers at the time of invoice for goods suppliers.
4. Common Mistakes in GSTR-1
Most GSTR-1 errors fall into a handful of categories. These are the ones we see repeatedly in businesses moving to PragatiCRM from manual filing:
- Wrong HSN code on invoice: Using the wrong 4 or 6-digit HSN code causes your HSN summary to misclassify the goods. The GSTN cross-checks HSN codes against your tax rates — a wrong HSN can trigger a mismatch notice.
- GSTIN error in B2B section: Entering a buyer's GSTIN incorrectly means their ITC claim fails. They will call you. If not corrected in the next return, they may dispute the invoice. Always validate GSTINs before filing.
- Forgetting credit notes: A credit note issued in April but not reported until June creates a discrepancy. Your buyer reduces their ITC in April; your GSTR-1 shows the original invoice amount. Mismatch in GSTR-2A/2B for the buyer.
- Missing HSN summary: Table 12 is a mandatory table from 2021 onwards. Leaving it blank or incomplete causes the filing to be flagged. Every invoice must be reflected in the HSN summary with the correct taxable value and tax amounts.
- Invoice values in books vs GSTR-1 not matching: If you prepare GSTR-1 manually from a separate Excel file and your Tally data differs — amounts, dates, or invoice numbers can diverge. Your CA has to reconcile two sets of numbers every month.
- Filing after due date — repeatedly: Occasional delays are manageable. Consistently late GSTR-1 filing shows as a compliance pattern in your GST profile, which can affect e-way bill generation, banking relationships, and GST scrutiny.
5. How to Prepare GSTR-1 Data
There are three common approaches to preparing GSTR-1 data. Each has a different time cost and error rate.
Method 1: Manual from Tally and Excel
Export invoices from Tally, cross-reference with any Excel records, classify B2B vs B2C manually, and enter the data into the GSTN portal or offline tool. This is how most small businesses filed GSTR-1 in 2018–2020. It takes 3–8 hours per month depending on invoice volume, and the error rate is high because classification and HSN assignment are done manually.
Method 2: Tally's built-in GST reports
Tally Prime has built-in GSTR-1 reports that organize your invoices for filing. If all your invoicing is done in Tally with correct HSN codes and GSTIN data, Tally can generate a reasonably clean GSTR-1. The limitation: Tally does not handle multi-location GSTINs well, does not track operational data (orders, CRM), and GSTIN validation is not automatic. Filing time is 45–90 minutes per month when Tally data is clean.
Method 3: GST-native billing software with automatic GSTR-1 export
When your invoices are created in software that auto-classifies B2B vs B2C (based on the buyer's GSTIN), auto-assigns CGST/SGST/IGST (based on state comparison), and validates HSN codes at entry — the GSTR-1 export is a one-click operation. The file is in the exact GSTN Excel format. Your CA downloads it and uploads it directly. Filing time: under 10 minutes per month.
Rule of thumb: If you are spending more than 30 minutes preparing GSTR-1 data every month — including the calls to and from your CA — your process is generating errors, not just consuming time. The root cause is almost always invoice data being stored in a system that was not designed for GST compliance.
6. How Billing Software Changes GSTR-1 Filing
The core advantage of GST-native billing software is that compliance is handled at the point of invoice creation — not at the end of the month when you are trying to file.
When a salesperson creates an invoice in PragatiCRM's GST invoicing module, the system automatically:
- Detects whether the buyer has a GSTIN (B2B) or not (B2C)
- Compares your location state with the buyer's state — applies CGST/SGST for intrastate, IGST for interstate
- Validates the HSN code against the product's configured tax rate
- Classifies the invoice correctly for the GSTR-1 table it belongs in
- Adds it to the HSN summary automatically
At month-end, the GSTR-1 export is a single click. The file is in the exact GSTN Excel format — B2B (Table 4), B2C (Table 7), HSN Summary (Table 12), and Credit Notes (Table 9) — all correctly populated. Your CA downloads it from PragatiCRM and uploads it to the GSTN portal. Filing time: under 10 minutes.
If you are on the Tally integration path, your CA also gets a Tally XML that imports your invoices directly into Tally with the correct ledger entries — CGST, SGST, IGST separated as Tally expects them.
7. Late Fees and What Happens If You Miss the Due Date
Filing GSTR-1 late carries a financial penalty and some operational consequences. Here is the current structure:
| Situation | Late fee per day | Maximum cap |
|---|---|---|
| Regular return (with outward supplies) | ₹50/day (₹25 CGST + ₹25 SGST) | ₹10,000 per return |
| NIL return (no outward supplies that month) | ₹20/day (₹10 CGST + ₹10 SGST) | ₹10,000 per return |
| IFF (Invoice Furnishing Facility under QRMP) | No late fee | — |
Beyond late fees, a delayed GSTR-1 has a downstream effect on your buyers. Your B2B buyers check GSTR-2B (auto-populated from your GSTR-1) to confirm their ITC position before filing. If your GSTR-1 is late, your invoices do not appear in their GSTR-2B on time — they may have to defer their ITC claim, which can create a cash flow problem for them. Some buyers will stop ordering from suppliers who consistently file late.
Amnesty and waiver history
The GST Council has periodically waived or reduced late fees for clearing arrears — particularly for FY 2017–18 through FY 2021–22. These amnesties do not reduce the risk of future penalties. The best approach: file on time, every time. A good billing software makes this achievable without significant effort.
Stop spending half a Sunday on GSTR-1 prep.
If you use billing software that auto-generates your GSTR-1 export, the process takes under 10 minutes. PragatiCRM does this with a single click — B2B, B2C, HSN Summary, and Credit Notes, all in the GSTN Excel format. Your CA uploads it directly to the portal.
See how GSTR-1 export works →Frequently Asked Questions
What is the due date for GSTR-1 in 2026?
For monthly filers (turnover above ₹5 Crore): 11th of the following month. For quarterly filers under the QRMP scheme (turnover below ₹5 Crore): 13th of the month following the quarter. For example, April 2026 GSTR-1 is due 11 May 2026 for monthly filers.
Can I amend GSTR-1 after filing?
Yes — amendments to GSTR-1 are made in the following month's return using the amendment tables (Tables 9A, 9B, 9C). You cannot directly edit a filed GSTR-1. If you discover an error after filing, you correct it in the next month's GSTR-1.
What is the difference between GSTR-1 and GSTR-3B?
GSTR-1 reports your outward supplies (sales) invoice by invoice — it is a data return. GSTR-3B is a summary self-assessment return where you calculate your net tax liability (output tax minus ITC) and pay the difference. GSTR-1 is filed first; GSTR-3B is filed after. Both are mandatory every month.
Do I need to file GSTR-1 even if I had no sales that month?
Yes — you must file a NIL GSTR-1 if you had no outward supplies during the period. A NIL return is simpler (nothing to enter except confirming no supplies) but it is still mandatory. Missing a NIL return attracts a late fee of ₹20/day, up to ₹10,000.
What is the IFF (Invoice Furnishing Facility) under QRMP?
Under the QRMP scheme, GSTR-1 is filed quarterly. But your B2B buyers need your invoice data monthly to claim ITC. The IFF lets you voluntarily upload B2B invoices for the first two months of the quarter — without filing a full GSTR-1 — so your buyers can see those invoices in their GSTR-2B on time. The third month's invoices are covered by the quarterly GSTR-1 filing.