How to File GST Returns — GSTR-1 and GSTR-3B Guide

Filing GST returns accurately and on time is critical for maintaining compliance and input tax credit eligibility. Understanding the different return forms and their purposes helps navigate the GST compliance calendar efficiently. ## GST Return Filing Overview Registered businesses must file returns based on their turnover and category. Regular taxpayers file GSTR-1 (outward supplies) monthly or quarterly depending on turnover, and GSTR-3B (summary return with tax payment) monthly. Composition dealers file GSTR-4 quarterly, while e-commerce operators have separate returns. The due dates are 11th of the following month for GSTR-1 (monthly filers), 13th for GSTR-1 (quarterly filers), and 20th for GSTR-3B. Filing returns late attracts interest of 18% per annum on tax liability and a late fee of Rs 50 per day (Rs 20 per day for CGST/SGST separately) up to a maximum of Rs 10,000. ## GSTR-1 Filing Process GSTR-1 captures all your outward supplies — sales invoices issued to customers. Log into the GST portal and navigate to Returns Dashboard. Select the filing period and click Prepare Online for GSTR-1. Enter invoice-level details including invoice number, date, customer GSTIN (if registered), HSN code, taxable value, and tax rates applied. The portal auto-populates data from e-way bill portal if invoice details were linked during e-way bill generation. Review the summary of outward supplies, including interstate and intrastate supplies, zero-rated exports, and NIL-rated supplies. File the return using digital signature or EVC after verifying all details are accurate. ## GSTR-3B Filing Process GSTR-3B is a summary return where you declare tax liability and claim input tax credit. The form has multiple sections capturing total outward supplies, eligible ITC, tax liability, and taxes payable. The ITC claiming section requires details of ITC available (from your purchases) and ITC reversal if any. ITC can only be claimed on invoices that appear in your supplier's GSTR-1, making reconciliation critical. After computing the final tax liability and ITC, pay any outstanding tax through online payment (net banking, NEFT/RTGS) or over-the-counter. File the return using DSC or EVC. A successfully filed return generates an Acknowledgment Reference Number. ## Common Mistakes to Avoid Missing invoice mismatches between GSTR-1 and GSTR-2A can lead to ITC mismatches. The GST portal now auto-populates GSTR-2B with ITC-eligible invoices, but regular reconciliation with supplier data prevents compliance issues. Filing nil returns even when there are no transactions is mandatory. Failing to file nil returns triggers late fees and can cause loss of input tax credit for recipients waiting for your GSTR-1 to claim credit.