GST Filing in India: Simple Guide to Returns, Deadlines, and Common Mistakes

When you run a business in India, GST filing, the process of reporting your sales, purchases, and taxes to the government under the Goods and Services Tax system. Also known as GST return filing, it’s not optional—it’s mandatory if your turnover crosses ₹20 lakh (₹10 lakh in special states). Skip it, and you risk fines, blocked e-way bills, or even suspension of your GST number. This isn’t paperwork for accountants alone. If you’re a freelancer, shop owner, or small manufacturer, you’re the one who needs to get it right.

There are different types of GST returns, but most small businesses only need to file GSTR-1, a monthly or quarterly report of all sales made and GSTR-3B, a simplified summary of tax liability and payments. GSTR-1 tells the government what you sold and to whom. GSTR-3B says how much tax you owe and how much you’ve already paid. If your input tax credit doesn’t match what your suppliers reported, your refund gets stuck. That’s why matching invoices matters more than you think.

Deadlines change every quarter, but the pattern is simple: if you file monthly, it’s due by the 11th of the next month. Quarterly filers have until the 13th after the quarter ends. Miss it? You’ll pay late fees—₹50 per day for CGST and ₹50 for SGST, up to ₹5,000. And if you’re expecting a GST refund? It won’t come until your returns are clean and your books are in order. Many businesses lose thousands because they file late or mix up HSN codes, forget to upload invoices, or don’t reconcile their GSTR-2B with their purchase records.

What you’ll find below are real, step-by-step guides from Indian business owners who’ve been through it. You’ll learn how to file GST online without a CA, how to fix common errors that trigger notices, and how to claim refunds faster. There’s no jargon here—just what works for small businesses, freelancers, and startups in India today.