Turning GSTR-2B and GSTR-3B Into a Working ITC Match: A Practical Excel Workflow
The portal gives you GSTR-2B as JSON and GSTR-3B as PDF. Neither is a reconciliation. This is how to get both into a single Excel workbook and run an invoice-level ITC match without retyping a line.
Every ITC reconciliation starts with a format problem. GSTR-2B downloads from the portal as a JSON file or a multi-sheet Excel that rarely lines up with how the purchase register is structured. GSTR-3B comes as a PDF built for reading, not for spreadsheets. Before any matching can happen, all of it has to become clean, columnar data in one place — and for most firms that step is still done by hand.
It does not need to be. The workflow below gets GSTR-2B, GSTR-3B and the purchase register into one workbook and produces an invoice-level match, and the only judgment involved is in reviewing the exceptions at the end.
Step 1 — Get every source into columnar Excel
- GSTR-2B: download the Excel or JSON from the portal for the period. The B2B sheet is the one that matters — invoice number, supplier GSTIN, invoice date, taxable value, and CGST / SGST / IGST / cess. Also keep the ITC Not Available sheet.
- GSTR-3B: convert the PDF to Excel so Table 4 (eligible ITC) and Table 3.1 (outward supplies) become figures you can reference rather than read.
- Purchase register: export from the accounting system with the same key fields — supplier GSTIN, invoice number, invoice date, taxable value, tax heads.
Step 2 — Build the match key and join
Create a single match key on both the GSTR-2B sheet and the purchase register — typically supplier GSTIN concatenated with the normalised invoice number. Use a lookup (XLOOKUP or INDEX/MATCH) from each side to the other so every line gets one of three states: matched both sides, in 2B only, in register only.
Step 3 — Classify every line
| Category | Test | Treatment |
|---|---|---|
| Exact match | Key matches; taxable value and each tax head agree within rounding | Eligible — include in the claim |
| Value mismatch | Key matches; a tax head or taxable value differs | Claim the GSTR-2B value; investigate the difference |
| In 2B, not in register | Key present only in GSTR-2B | Book the missing purchase, or reject in IMS if not yours |
| In register, not in 2B | Key present only in the purchase register | Defer the claim; add to supplier follow-up |
| Blocked / not available | Appears in 2B ITC Not Available, or falls under Section 17(5) | Exclude from the claim; note the reason |
Step 4 — Tie the claim back to GSTR-3B
Sum the eligible category (plus the claimable portion of value mismatches) by tax head and compare it to Table 4A of the converted GSTR-3B. From the July 2026 tax period this figure cannot exceed the auto-populated GSTR-2B balance, so the reconciliation total is also a filing pre-check: if your worked figure is higher, the return will not submit until the excess is resolved.
Step 5 — Carry forward the exceptions
The in-register-not-in-2B list is a rolling document, not a monthly throwaway. An invoice that misses this month's 2B may land next month when the supplier files; the claim then becomes available in that later period. Track each pending item with its invoice date so the Section 16(4) outer limit is visible before the credit expires.
Where automation removes the manual step
Steps 2 to 5 are spreadsheet work that a template handles once it is built. Step 1 — getting clean data out of a GSTR-3B PDF and a portal GSTR-2B export — is the part that stays manual for most firms, and it is also the part that introduces transcription errors into a process whose whole purpose is to catch them.
GST Reco Pro converts GSTR-1 and GSTR-3B PDFs into clean, column-matched Excel — up to 24 files per batch, entirely in the browser, nothing uploaded. It removes the one manual step in the workflow above, so the reconciliation template runs on consistent data every month.
Convert GSTR PDFs to Excel for reconciliation →Related reading: how the same local-first, bulk approach handles 1,000+ TDS challan PDFs.
Read the bulk TDS challan workflow →Frequently Asked Questions
How do I convert a GSTR-2B JSON file to Excel?
The GST portal offers a GSTR-2B download in both JSON and Excel formats for each period — the Excel version is usually enough for reconciliation. If you only have the JSON, the portal's offline matching tool or a spreadsheet import can flatten it; the B2B section is the sheet you need for invoice-level ITC matching.
How do I convert a GSTR-3B PDF to Excel?
Use a converter that reads the GSTR-3B table structure. GST Reco Pro extracts Table 3.1 outward supplies and Table 4 ITC from GSTR-3B PDFs into Excel in the browser without uploading the file, so the figures can be referenced in a reconciliation rather than read off a PDF.
What is the best way to match a purchase register against GSTR-2B?
Build a single match key of supplier GSTIN plus normalised invoice number on both sides, join with a lookup, then classify each line as exact match, value mismatch, in-2B-only, in-register-only, or blocked. Review only the non-exact categories.
Why do so many invoices show as mismatched when they are actually fine?
Almost always a formatting difference in the key — invoice numbers with leading zeros, slashes or spaces on one side but not the other, or GSTINs with inconsistent case. Normalise both fields on both sides before matching.
What happens to an invoice that is in my purchase register but not in GSTR-2B?
Defer the claim. If the supplier files late, the credit becomes available in the GSTR-2B of the period they file in. Track it with its invoice date so you can claim it before the Section 16(4) deadline for that financial year.