Reconciliation⏱ 15 min

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GSTR-1 vs GSTR-3B

Catch mismatches between your outward supply declaration and summary filing before the department does.

GSTR-1 carries invoice-level outward supply data. GSTR-3B carries the summary. When they don't match, GSTN's system flags it and issues ASMT-10 scrutiny notices. GSTAgent cross-checks all four Table 3.1 rows — B2B taxable value, exports, nil-rated, and RCM — and quantifies your demand exposure before you file.

Sec 3.1(a)Seller-sideASMT-10Demand risk

Start GSTR-1 vs 3B Check →

The Problem

Why this needs to be automated

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GSTN's system matches them automatically

GSTN's ANEX system compares GSTR-1 and GSTR-3B data for every taxpayer every month. Any shortfall in 3B vs 1 generates an auto-notice. Most CAs don't check this before filing.

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ASMT-10 notices are increasing

Post-2022, GSTN has accelerated scrutiny notices under Section 61. A GSTR-1 vs 3B mismatch of even ₹5,000 can trigger a formal notice requiring a response within 30 days.

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DRC-03 interest compounds from filing date

If shortfall is confirmed, interest at 18% p.a. runs from the original due date of the 3B in which the shortfall occurred — not from the notice date.

Regulatory Context

The law that makes this matter

Sec 61

Scrutiny of returns

Officer may scrutinise returns for correctness. GSTR-1 vs 3B mismatch is the most common trigger for ASMT-10 scrutiny notice.

Sec 3.1(a)

Outward taxable supplies

B2B taxable value declared in GSTR-1 must match the outward supply figure in GSTR-3B Table 3.1(a). Any shortfall in 3B is a recoverable demand.

Sec 50

Interest on delayed payment

Interest at 18% p.a. from due date of return in which shortfall occurred. Compounds monthly if unpaid.

How It Works

4 steps. Mostly automated.

Upload GSTR-1 and GSTR-3B

Upload JSON or PDF exports of both returns for the period. GSTAgent extracts all table values automatically.

Auto-cross-check all 4 rows

Table 3.1(a) B2B, 3.1(b) exports, 3.1(c) nil-rated, 3.1(d) RCM — each row compared between GSTR-1 aggregate and GSTR-3B declared value.

Demand risk quantified

Any shortfall in 3B vs 1 is flagged with exact rupee exposure, interest computation at 18% p.a., and DRC-03 action recommendation.

File DRC-03 before notice

Voluntary payment via DRC-03 before department notice closes the gap and avoids penalty. GSTAgent shows the exact amount to pay.

Sample Output

What you actually see

Sample data — Metro Print Works Pvt. Ltd · FY 2026-27

Table 3.1(a) GSTR-1

₹48,24,300

Table 3.1(a) GSTR-3B

₹47,90,000

Shortfall in 3B

₹34,300

GST on shortfall @18%

₹6,174

Interest @18% p.a. (45 days)

₹136

Total DRC-03 liability

₹6,310

Sample data for illustration only. Actual results depend on your client's Tally data. Not professional tax advice.

Edge Cases

How GSTAgent handles the tricky ones

Scenario	GSTAgent Output
Amendment invoice in GSTR-1 not adjusted in 3B	Flagged as amendment mismatch — show net effect
Credit notes reducing outward supply	Net taxable value computed after credit note adjustment
Export invoices under LUT vs with IGST	Separated — LUT exports not counted in tax demand
3B filed before 1 in same month	Timing flag — wait for 1 to be filed before concluding mismatch

Table rows cross-checked

18%

Interest p.a. auto-computed

30 days

ASMT-10 response window

15 min

vs hours of manual checking

FAQ

Common questions

How often does GSTN issue ASMT-10 notices?

GSTN's system runs automated matching every month. Notices are issued in batches — frequency has increased significantly since 2023.

Can I use PDF exports instead of JSON?

Yes — GSTAgent's AI PDF parser extracts all table values from PDF exports of GSTR-1 and GSTR-3B automatically.

What if the mismatch is due to a timing difference?

GSTAgent flags timing differences separately — if an invoice was reported in a later GSTR-1 amendment, it's shown as a timing item not a demand.

Should I file DRC-03 even for small amounts?

Yes — voluntary payment via DRC-03 prevents penalty. Even ₹100 shortfall can be noticed and if not paid voluntarily attracts 100% penalty if department raises it.

Does this cover RCM liability mismatch?

Yes — Table 3.1(d) RCM declared in GSTR-1 (inward) is cross-checked against GSTR-3B Table 3.1(d). Missed RCM liability is flagged.

Ready to run this workflow?

A GSTAgent subscription code is required. CA firm plans from ₹1,400/month for 10 clients.

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