Every regular GST-registered business files two main returns: GSTR-1 (the detail of your sales) and GSTR-3B (a summary where you actually pay the tax). If GSTR-1 is the list, GSTR-3B is the settlement. This guide keeps it simple.
New to GSTR-1? Read our companion guide on how to file GSTR-1 first — the two work together.
What Is GSTR-3B?
GSTR-3B is a self-declared summary of a tax period: your total outward sales, the tax on them, the input tax credit you are claiming on purchases, and the net tax you pay after adjusting the two. You do not list every invoice here — just the totals.
When Is It Due?
- Monthly filers — by the 20th of the next month
- QRMP filers (turnover up to ₹5 crore, filing quarterly) — by the 22nd or 24th of the month after the quarter, depending on your state
Late filing attracts ₹50 per day (₹20 for nil returns) plus 18% annual interest on unpaid tax, so the date matters.
The Tables That Matter
| Table | What goes in it |
|---|---|
| 3.1 | Outward supplies — your taxable sales and the tax on them |
| 3.2 | Inter-state sales to unregistered persons (a breakup of 3.1) |
| 4 | Eligible Input Tax Credit from your purchases |
| 5 | Exempt, nil-rated and non-GST inward supplies |
| 6.1 | Payment of tax — net cash you pay after credit |
Your GSTR-3B outward tax should match the GSTR-1 you filed for the same period. Mismatches are the number one reason for GST notices. Software that produces both from the same sales data keeps them in sync automatically.
Common Mistakes to Avoid
- Claiming more input credit than your suppliers have actually reported (check GSTR-2B first)
- Forgetting to reverse credit on exempt sales
- Filing 3B without reconciling it to 1 — the top cause of scrutiny
- Missing the due date on a nil month (a nil return is still mandatory)
How Billing Software Prepares It
You should never build GSTR-3B by hand from a register. Billux adds up your outward supplies and tax automatically and gives you a GSTR-3B summary that maps to the portal tables — so you review the numbers and enter them, rather than calculating them. It also exports GSTR-1 and reconciles GSTR-2B, keeping the three consistent.
The Bottom Line
GSTR-3B is a summary, not a mystery. Know the tables, respect the date, and let your billing data do the arithmetic.
Get GST-ready billing free at billux.in/register.
