Understand the difference between GSTR-1 and GSTR-3B returns for Indian GST compliance. Learn when to file each, what details they cover, and deadlines.
What is GSTR-1 and When Do You File It?
GSTR-1 is your outward supply return—a detailed record of all goods and services you've sold during a GST month. If your annual turnover exceeds ₹40 lakh (₹20 lakh for services, ₹10 lakh for special-category states like Assam and Himachal Pradesh), you must file GSTR-1 by the 11th of the following month.
GSTR-1 requires you to list:
- Every invoice issued to registered and unregistered customers
- HSN/SAC codes for each item
- Taxable values and GST collected
- Separate sections for inter-state and intra-state supplies
Understanding GSTR-3B: Self-Assessment and Payment
GSTR-3B is your monthly self-assessment return. Here, you declare both inward (purchases) and outward (sales) supplies, calculate your tax liability, claim input tax credit (ITC), and pay any balance due. All businesses must file GSTR-3B by the 20th of the following month, regardless of turnover.
Key elements:
- Total GST collected on sales
- Total ITC available from purchases
- Net tax payable or refund due
- Summary figures only (no invoice-level details)
Key Differences at a Glance
| Aspect | GSTR-1 | GSTR-3B |
|---|---|---|
| Purpose | Invoice-level sales details | Self-assessment & tax payment |
| Deadline | 11th of next month | 20th of next month |
| Mandatory for | Turnover above threshold | All registered dealers |
| Details required | Every invoice | Summary totals only |
| ITC claimed | No | Yes |
Filing Strategy for Small Businesses
File GSTR-1 first, as your outward supplies form the basis for what GSTR-3B calculates. Mismatches between the two raise audit flags, so maintain consistent records.
If your turnover is below the threshold, you're exempt from GSTR-1 but still file GSTR-3B for payment purposes.
Stay compliant effortlessly—use our free GST compliance calculator at gsthelp.in to verify your filing obligations, check deadlines, and ensure accuracy before submission.