GST reconciliation matches your returns with your books on three tracks: GSTR-2B vs purchase register (ITC), GSTR-1 vs sales register (output), and GSTR-3B vs both (tax paid). Under Rule 36(4), ITC can be claimed only to the extent it appears in GSTR-2B — there is no 5% provisional buffer. Annual reconciliation via GSTR-9 is mandatory above ₹2 crore and GSTR-9C above ₹5 crore.
The Three Core Reconciliation Tracks
Every month, before you file GSTR-3B, three data sets must agree. If they don't, you risk ITC reversal, interest and penalty.
| Reconciliation | Source A (Returns) | Source B (Books) | Purpose |
|---|---|---|---|
| Outward supply match | GSTR-1 (filed) | Sales register / ledger | Ensure all sales are declared; no omissions |
| ITC match | GSTR-2B (auto) | Purchase register | Confirm eligible ITC; catch supplier non-filers |
| Tax payment match | GSTR-3B | GSTR-1 + GSTR-2B | Tax paid = output tax − eligible ITC |
| Annual reconciliation | GSTR-9 | Audited books / P&L | Full-year accuracy check · mandatory > ₹2cr |
| Reconciliation statement | GSTR-9C | GSTR-9 vs books | Self-certified differences · mandatory > ₹5cr |
GSTR-2B is a static statement generated on the 14th of each month; it is the definitive basis for ITC under Rule 36(4).
The 5% provisional-ITC buffer was withdrawn from 1 January 2022. Section 16(2)(aa) with Rule 36(4) now allows ITC only to the extent an invoice appears in your GSTR-2B. If a supplier has not filed their GSTR-1, that credit is simply not available until they do — you cannot claim it on the strength of a valid invoice alone.
GSTR-2B Reconciliation — Step by Step
GSTR-2B is generated on the 14th of each month and locks the ITC available for that period. Reconcile it against your purchase register before every GSTR-3B.
- 1Download 2BExcel/JSON from the GST portal
- 2Export booksPurchase register, same period
- 3MatchGSTIN + invoice no + date + tax
- 4ClaimOnly matched ITC in GSTR-3B
| Step | Action | How / Tool |
|---|---|---|
| 1 | Download GSTR-2B (Excel/JSON) for the period | GST portal → Returns → GSTR-2B |
| 2 | Export purchase register for the same period | Tally / Zoho Books / Busy / ERP |
| 3 | Match each invoice by GSTIN + no. + date + tax | Excel VLOOKUP or recon software |
| 4 | Flag invoices in books but not in 2B | Supplier not filed — follow up / defer ITC |
| 5 | Flag invoices in 2B but not in books | Missing entry or duplicate — verify |
| 6 | Check value / tax differences | Ask supplier to amend in next GSTR-1 |
| 7 | Claim only matched ITC in GSTR-3B | Carry unmatched credit to a later month |
Unmatched ITC is not lost — it can be claimed once the supplier files, within the Section 16(4) time limit.
Piling up unmatched ITC every month? Let us reconcile your GSTR-2B and file cleanly.
Get Reconciliation Help →Common Mismatches & How to Fix Them
Reconciliation almost always surfaces the same handful of differences. Here is what each one means and the fix.
| Mismatch | Cause | Resolution |
|---|---|---|
| Invoice in books, not in GSTR-2B | Supplier has not filed GSTR-1 | Follow up; claim ITC when it appears in 2B |
| 2B ITC higher than books | Missing purchase entry | Locate invoice; post entry; verify it is genuine |
| Tax value differs on same invoice | Supplier amended the invoice | Update books; accept/reject the amendment entry |
| Credit note not reconciled | Supplier issued a credit note | Post it; reduce ITC by the reversal |
| GSTR-1 vs sales register gap | Invoice added / amended after filing | Correct in the next period's GSTR-1 |
| IGST vs CGST/SGST mismatch | Wrong place of supply | Amend invoice; adjust heads in GSTR-3B |
| ITC claimed on exempt supply | Mixed use not identified | Reverse ITC under Rule 42 / 43 |
| Excess ITC in 3B vs 2B | Claimed before supplier filed | Reverse excess; re-claim in the correct month |
The 180-day rule (2nd proviso to Sec 16(2)) also requires ITC reversal if you have not paid the supplier within 180 days of the invoice.
Businesses that only reconcile at GSTR-9 time discover a year of supplier non-filing and 24% interest all at once. A tight monthly 2B match keeps ITC recoverable, interest at zero and the annual return a formality.
Annual Reconciliation — GSTR-9 & GSTR-9C
The annual return consolidates the year and reconciles it with your audited books. Who must file and by when:
| Return | Who must file | Due date | Late fee |
|---|---|---|---|
| GSTR-9 (Annual) | Turnover > ₹2 crore (mandatory) | 31 December | ₹200/day (₹100 CGST + ₹100 SGST) |
| GSTR-9 (Optional) | Turnover ≤ ₹2 crore | 31 December | No penalty if not filed |
| GSTR-9C (Reconciliation) | Turnover > ₹5 crore (self-certified) | 31 December | As per GSTR-9 late-fee slab |
CA/CMA certification of GSTR-9C was removed from FY 2020-21 (Sec 35(5) omitted); the taxpayer now self-certifies. GSTR-9C late fee is capped by turnover slab.
- GSTR-1 total vs GSTR-3B outward
- GSTR-3B ITC vs GSTR-2B available
- ITC reversals (Rule 42/43, 180-day)
- RCM liability paid & ITC taken
- Turnover: books vs GSTR-9
- Tax paid: books vs GSTR-3B
- Amendments & credit notes captured
- HSN summary tallied
- Late fee / interest provided
- GSTR-9C differences explained
GST 2.0 (effective 22 September 2025) rationalised goods/service rates but did not change these return or reconciliation rules — the same three-way match and annual thresholds apply for FY 2025-26.
Interest & Penalty on Mismatches
Unresolved mismatches convert into interest and penalty. Fix them before the department raises a demand.
| Default | Interest / Penalty | Section |
|---|---|---|
| Wrongly availed & utilised ITC (reversed later) | 24% p.a. from utilisation to reversal | Sec 50(3) |
| Short / late payment of output tax | 18% p.a. from due date | Sec 50(1) |
| Non-payment — bona fide error | ₹10,000 or 10% of tax (higher) | Sec 122 |
| Fraud / wilful misstatement | Up to 100% of tax + prosecution | Sec 122 / 132 |
Voluntary reversal in GSTR-3B (Table 4B) and payment before a show-cause notice materially reduces penalty exposure.
Found a mismatch at year-end? Get it reconciled and disclosed before a notice.
Talk to a GST Expert →- Returns & GSTR-2B: gst.gov.in
- CBIC-GST law & rules: cbic-gst.gov.in
- ITC ceiling: Section 16(2)(aa) & Rule 36(4), CGST
- Interest: Section 50(1) & 50(3), CGST Act 2017
- GSTR-9/9C thresholds: Notification 15/2025-CT (17 Sep 2025); Sec 35(5) omitted (FY 2020-21)
Disclaimer: This guide is general information based on the law and notifications in force when it was last updated. It is not professional advice for your case — rates, thresholds and due dates change, so check the current position or speak to our CA team before you act on it.