GST Reconciliation: GSTR-1, GSTR-3B & GSTR-2B ITC Mismatch Explained

GST reconciliation means making sure four numbers agree: your books, what you declared in GSTR-1, what you paid through GSTR-3B, and what your suppliers reported to give you Input Tax Credit in GSTR-2B. When any two of these drift apart, the GST portal now catches it automatically and sends a system-generated notice — not a human reviewer, an algorithm, usually within days of the mismatch appearing. Call or WhatsApp us on 70 9232 9232 if you’re already staring at one of these notices and need it handled properly.

Table of Contents

• GSTR-2B and GSTR-2A aren’t the same thing
• Why ITC matching became strict
• DRC-01C — when you’ve claimed more ITC than GSTR-2B shows
• DRC-01B — when your GSTR-1 liability exceeds what you paid
• What usually causes the mismatch
• A monthly reconciliation actually prevents this
• What we actually do
• Frequently asked questions
• What’s the difference between GSTR-2A and GSTR-2B?
• Can I still claim provisional ITC that isn’t in GSTR-2B?
• What is a DRC-01C notice?
• What happens if I don’t respond to a mismatch intimation?
• How often should GST reconciliation be done?
• Talk to a consultant, not a call centre

GSTR-2B and GSTR-2A aren’t the same thing

This is the single most common confusion we see. GSTR-2A is a live, dynamic statement — it updates continuously as suppliers file or amend their GSTR-1. GSTR-2B is a static, once-a-month snapshot, auto-generated on the 14th of the following month, and it’s GSTR-2B — not 2A — that actually determines how much ITC you’re allowed to claim in that period’s GSTR-3B. If your accountant is reconciling against 2A, they’re reconciling against a moving target that doesn’t match what the law says you can claim.

Why ITC matching became strict

Until late 2021, businesses could provisionally claim a percentage of ITC that hadn’t yet shown up in their supplier statements — a buffer that shrank over successive amendments to Rule 36(4), from 20%, to 10%, to 5%. That buffer was removed entirely effective 1 January 2022, when Section 16(2)(aa) made it a hard condition: you can only claim ITC that actually appears in your GSTR-2B for that period. There is no grace percentage anymore. If a supplier hasn’t filed their GSTR-1, that credit simply isn’t available to you yet, regardless of whether you’ve already paid them the GST on their invoice.

DRC-01C — when you’ve claimed more ITC than GSTR-2B shows

Under Rule 88D, the portal now runs an automated check every period comparing the ITC you claimed in GSTR-3B against what’s actually available in GSTR-2B. If your claim exceeds the 2B figure beyond a prescribed threshold, you get a system-generated DRC-01C intimation. You then have a fixed window to respond in Part B — either pay the excess through DRC-03 along with interest under Section 50, or explain the gap with your own reconciliation. Ignore it, and you risk being blocked from filing your next GSTR-1 or IFF under Rule 59(6), with escalation to formal demand proceedings under Section 73 or 74.

DRC-01B — when your GSTR-1 liability exceeds what you paid

The mirror-image check, under Rule 88C, compares your declared outward tax liability in GSTR-1 against what you actually paid in GSTR-3B. If GSTR-1 shows more liability than GSTR-3B reflects, you get a DRC-01B intimation with the same consequence — respond and resolve it, or risk the same GSTR-1/IFF blocking that DRC-01C carries.

What usually causes the mismatch

• Supplier delay — your vendor hasn’t filed their GSTR-1 yet, so their invoice hasn’t reached your GSTR-2B.
• Wrong GSTIN on an invoice — the credit lands in someone else’s 2B, not yours.
• Timing lag — you booked the purchase in one month, the supplier filed it in the next.
• HSN or rate errors — the supplier declared a different rate or code than what’s on your invoice.
• Credit notes not reflected — a return or discount adjustment your supplier hasn’t filed yet.

Most of these resolve themselves once the supplier files correctly — the real risk isn’t the mismatch existing, it’s not catching it before the department’s automated checks do.

A monthly reconciliation actually prevents this

The businesses that get DRC-01C or DRC-01B intimations are almost always the ones reconciling annually, right before GSTR-9, instead of monthly. By then, a mismatch from eight months ago is much harder to trace back to a specific invoice or supplier conversation. A monthly reconciliation — books against GSTR-1, GSTR-1 against GSTR-3B, GSTR-3B against GSTR-2B, every single period — catches a mismatch while it’s still one recent invoice, not a year’s worth of drift you’re untangling in November under deadline pressure before the 31st December GSTR-9 filing date.

What we actually do

• Monthly 4-way matching — books, GSTR-1, GSTR-3B, and GSTR-2B checked against each other before filing, not after.
• Supplier follow-up — when a credit is missing because a vendor hasn’t filed, we flag it so you can chase the specific invoice.
• DRC-01B / DRC-01C response handling — if a mismatch notice has already landed, we prepare the reconciliation or payment response within the response window.
• Direct access to your consultant — no call centre, the same person every month.

Frequently asked questions

Talk to a consultant, not a call centre

Whether you’re setting up monthly reconciliation properly or already holding a mismatch notice, call or WhatsApp 70 9232 9232 and we’ll take it from there. GST Return Filing, including reconciliation, starts at ₹5,990 + GST per year for up to 30 bills a month. Rated 5.0★ across 1,000+ Google reviews, serving businesses since 2017.

Want the full picture on filing itself? See our how GST Return Filing works. Manufacturing or exporting, where reconciliation across multiple vendors and states gets more complex? See our guide for manufacturers & exporters. Missed a due date and now facing late fees too? See our GSTR-3B late fee & interest guide.