GSTR-3B software: from auto-draft to tax payable
GSTR-3B is where GST becomes money — your outward liability, your input tax credit, and the balance to pay. 24eTax drafts it from your books and your GSTR-2B, shows every difference, and works out the set-off before you commit a rupee.
Updated: 23 August 2026 — reviewed against current GSTN behaviour.
What is GSTR-3B?
GSTR-3B is the monthly (or QRMP quarterly) self-declared summary return: total outward taxable supplies and the tax on them, input tax credit availed, and the net tax paid in cash after set-off. Unlike GSTR-1, it is not invoice-wise — which is exactly why errors hide in it so easily: the totals must agree with your GSTR-1, your books and your GSTR-2B, and nothing on the portal forces them to.
The three numbers that must agree
- Outward liability — what your books say you sold (and what your GSTR-1 reported).
- Input tax credit — what you claim, against what your suppliers actually reported in your GSTR-2B.
- Tax payable — liability minus ITC, split across IGST, CGST and SGST in the order the set-off rules require.
How 24eTax handles it
Auto-drafted from your data
Outward tables come from your committed sales; ITC tables start from your downloaded GSTR-2B — the same sources the law expects you to reconcile against.
Three-way difference report
Books vs GSTR-1 vs 3B draft, and ITC claimed vs 2B — every difference is listed with the documents behind it, so you fix causes, not symptoms.
Set-off worked out (rule 88A)
The app proposes the credit utilisation order the rules require — IGST credit first, then the CGST/SGST order that minimises cash outgo — and shows the cash payable per head.
Portal working, in-app
Fetch GSTN's auto-liability figures and compare with your draft; the differences tell you what GSTN already knows about your period.
Interest & late-fee aware
Due dates per GSTIN (including the QRMP 22nd/24th split by state), with late fee and interest computed when a period slips.
Filed periods freeze
After filing, the period's documents lock and corrections flow through the next period — your books can never quietly diverge from what was declared.
Frequently asked questions
What is the due date for GSTR-3B?
Monthly filers: the 20th of the following month. QRMP filers: the 22nd or 24th of the month after the quarter, depending on your state. 24eTax shows the exact dates for your GSTINs and reminds you ahead of them.
Why doesn't my GSTR-3B match my GSTR-1?
Common causes: credit notes reported in one but not the other, amendments, advances, or simple period differences. 24eTax's difference report lists each document behind the mismatch so it can be fixed before filing rather than explained after a notice.
Can I claim all the ITC in my books?
Only credit that appears in your GSTR-2B is safely claimable. The app reconciles books vs 2B, flags what's missing, and gives you the supplier-wise list to chase — before you claim, not after a notice.
Does 24eTax file GSTR-3B or just prepare it?
The full working is prepared in-app — auto-draft, differences, set-off and cash payable, with GSTN's own auto-liability fetched for comparison. Filing is completed with your EVC; where a portal-side quirk affects a period, the app tells you honestly and hands you a portal-ready working instead of guessing.
What is rule 88A, in one line?
It's the rule that fixes the order of using credit: IGST credit must be used first (against IGST, then CGST/SGST in any order), before CGST and SGST credit are touched — and SGST credit can never pay CGST or vice versa.
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