How to file GSTR-3B without surprises
Updated: 23 August 2026 · Reviewed for the current GST 2.0 rate structure and portal behaviour.
GSTR-3B is the summary return where tax is actually paid. It has no invoice-level detail — which is why it goes wrong quietly. This guide walks the working: liability, credit, set-off, cash.
1. What GSTR-3B declares
Monthly (or quarterly under QRMP), GSTR-3B declares: your outward taxable supplies and the tax on them (Table 3.1), inter-state supplies to unregistered persons and composition dealers (3.2), the input tax credit you avail and reverse (Table 4), exempt/nil-rated inward supplies (Table 5), and the tax paid — through credit and in cash (Table 6). Due dates: the 20th of the next month for monthly filers; the 22nd or 24th after the quarter for QRMP, depending on your state.
2. Building the working
- Outward liability comes from your sales register: taxable value and tax per head (IGST/CGST/SGST/cess), net of credit notes. It should equal what your GSTR-1 for the period reported.
- Eligible ITC starts from your GSTR-2B for the period — not from your purchase register. Add RCM liability (which you pay in cash and may claim as credit), subtract ineligible and blocked credits, and reverse credit where required (for example supplier payment beyond 180 days).
- Net payable = liability − credit utilised, per head. What credit cannot cover is paid in cash through the electronic cash ledger before filing.
3. The set-off order (rule 88A)
Credit cannot be used in any order you like:
- IGST credit is used first — against IGST liability, then against CGST and SGST in any proportion, until IGST credit is exhausted.
- Then CGST credit pays CGST (never SGST), and SGST credit pays SGST (never CGST).
- Cash pays whatever remains, head by head.
The order matters: a poor manual set-off can leave you paying cash under one head while credit idles under another.
Do this automatically: 24eTax prepares this entire workflow from your own invoices — validated, reconciled and ready to file with your EVC. Start free →
4. The reconciliations that prevent notices
| Compare | Because |
|---|---|
| 3B outward vs GSTR-1 | The portal compares them too; persistent gaps invite intimation notices (DRC-01B). |
| 3B ITC vs GSTR-2B | Credit claimed beyond 2B is the single most common notice trigger. |
| 3B vs books | Your books are the truth the other two must trace back to — differences mean something was billed, credited or classified inconsistently. |
5. Late fee and interest
Filing late attracts a per-day late fee (with caps linked to turnover, and a lower fee for nil returns) and 18% p.a. interest on tax paid late in cash. Interest runs from the due date to the payment date — so even when a filing must slip, depositing the cash liability on time limits the damage.
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