How to File GSTR-1 Online: Step-by-Step Process

GSTR-1 doesn't involve tax payment (that's GSTR-3B) — its entire purpose is reporting invoice-level detail on your outward supplies accurately, since this is what generates your buyers' input tax credit via their GSTR-2B. Getting the detail right here matters more than in almost any other return.

Step 1: Gather Your Sales Data for the Period

Compile every outward supply invoice for the month/quarter — B2B (to GST-registered buyers), B2C large (unregistered buyers, invoice value above ₹1 lakh, inter-state), B2C small (aggregated by state), exports, credit/debit notes issued, and any advances received against future supplies.

Step 2: Log In and Select the Return Period

On the GST portal, go to Returns Dashboard, select the financial year and the specific month/quarter, and choose GSTR-1.

Step 3: Enter Invoice Details Table-by-Table

• Table 4 (B2B invoices): Invoice-wise detail — buyer GSTIN, invoice number/date, taxable value, and tax rate/amount split by CGST/SGST/IGST. GSTIN accuracy here is what determines whether the buyer's ITC actually reflects correctly.
• Table 5 (B2C large): Invoices to unregistered buyers above ₹1 lakh for inter-state supply, entered invoice-wise
• Table 7 (B2C small): All other unregistered-buyer sales, aggregated by state and tax rate rather than invoice-wise
• Table 9 (amendments): Corrections to invoices reported in an earlier period
• Table 12 (HSN summary): HSN/SAC-wise summary of all supplies for the period — mandatory detail level depends on your turnover slab

Step 4: Use the Invoice Furnishing Facility (QRMP Filers Only)

If you're on the Quarterly Return Monthly Payment (QRMP) scheme, you can optionally upload B2B invoice details monthly via the IFF for the first two months of the quarter (so your buyers get timely ITC without waiting for the full quarterly GSTR-1), while the complete GSTR-1 itself is still filed quarterly.

Step 5: Preview, Validate, and File

Use the "Preview" option to review the summary before submission. File using DSC (mandatory for companies/LLPs) or EVC (OTP-based, for individuals/proprietors). Once filed, you receive an Acknowledgement Reference Number (ARN).

Common Filing Errors

• Wrong buyer GSTIN: The single most common cause of a buyer's ITC not reflecting — a single-digit typo routes the credit to the wrong GSTIN entirely
• Invoice placed in the wrong table: A B2B invoice mistakenly entered under B2C small doesn't generate ITC for the actual GST-registered buyer
• Missing credit/debit notes: Forgetting to report a credit note issued against a return/discount overstates your reported turnover and creates a mismatch at reconciliation
• Filing before GSTR-3B of the previous period: not a data error, but a sequencing block — GSTR-1 can't be filed at all until the prior period's 3B is filed

Since GSTR-1 errors show up as someone else's blocked input tax credit rather than an immediate cost to you, they're easy to under-prioritize — but they routinely become a client relationship issue once the buyer notices the missing credit. Our GST return filing service validates invoice-level detail before filing to catch GSTIN and table-placement errors upfront.