Purchase Register Format for GST and Tally in 2026

Key Takeaways

There is no prescribed GST purchase register format, but certain fields are effectively mandatory to defend ITC, capture supplier GSTIN, invoice number, date, taxable value, and tax amounts on every row.
Use GSTR-2B as the reconciliation anchor, structure your register so five keys match exactly, supplier GSTIN, document number, document date, taxable value, and tax amounts.
Flag special cases clearly, add separate indicators for RCM and imports so they are not falsely flagged as missing in 2B.
Enable Tally bill-wise details at both company and creditor ledger levels, post purchases with New Reference and clear payments with Against Reference.
Build Excel validations for GSTIN format, duplicate invoices, and IGST vs CGST, SGST splits, preventing bad data that leads to ITC reversals and interest.

Why Your Purchase Register Decides Your ITC

Missed ITC is rarely about bad intentions, it is about a register that was not built for reconciliation. When your columns do not match GSTR-2B keys or your Tally ledger mapping is off, you lose credit you legitimately earned.

A purchase register in GST has no prescribed format under CBIC/GSTN, but the fields required to defend Input Tax Credit under Section 16(2) of the CGST Act, 2017 are effectively mandatory. Get those fields right, validate them at entry, and your register doubles as a reconciliation and Tally posting tool.

Purchase Register Format, The Short Answer

A purchase register format for GST in India must capture the six ITC-qualifying fields from Section 16(2)(a) of the CGST Act, plus GSTR-2B matching keys and Tally posting fields, across every invoice row.

Supplier Identity — Supplier Name, Supplier GSTIN, Supplier State, source: Section 16(2)(a), CGST Act
Document Details — Invoice or Debit Note number, Invoice Date, Document Type, source: Section 16(2)(a), CGST Act
Value and Tax — Taxable Value, IGST, CGST, SGST, Cess, source: Rule 36(2), CGST Rules
Supply Classification — Place of Supply state, Intra or Inter flag, source: Section 8, IGST Act
E-Invoice Fields — IRN, Acknowledgement Number, Acknowledgement Date, source: Notification 10/2023 – Central Tax
Special Type Flag — RCM Y or N, Import Y or N, Self-Invoice reference, source: Section 31(3)(f), CGST Act
Tally Mapping — Expense or Asset Ledger, Cost Centre, Bill Reference, New Ref
2B Status — Matched, Mismatch, Missing, Not Applicable, source: Section 16(2)(aa), CGST Act

The most common mistake is building a register optimised for accounts payable posting but omitting GSTR-2B matching keys, Supplier GSTIN, document number, document date, taxable value, and tax amounts. These five fields are what GSTN uses to auto-populate 2B, and they must match exactly, character for character, for reconciliation to work.

What Columns Must Your GST Purchase Register Have In 2026?

No official template exists, but the implied field list from Section 16(2) of the CGST Act and Rule 36(2) of the CGST Rules covers everything a scrutiny or audit would ask for.

Mandatory ITC Fields

Supplier Name, as registered with GSTN
Supplier GSTIN, 15-character alphanumeric, validated for structure
Invoice Number, exact string from the tax invoice, case-sensitive
Invoice Date, DD/MM/YYYY, must fall within the relevant financial year
Taxable Value, pre-GST value of supply
IGST Amount, for inter-state supplies
CGST Amount, for intra-state supplies
SGST Amount, for intra-state supplies
Cess Amount, for notified goods
Place of Supply, state name or state code, determines IGST vs CGST, SGST split under Section 8 of the IGST Act, 2017
HSN Code or SAC Code, mandated under Rule 46 of the CGST Rules
Date of Receipt of Goods or Services, Section 16(2)(b) of the CGST Act makes actual receipt a condition for ITC

E-Invoice Fields, Businesses Over ₹5 Crore Turnover

From 1 August 2023, businesses with aggregate turnover exceeding ₹5 crore in any preceding financial year from FY 2017–18 must generate e-invoices under Notification 10/2023 – Central Tax. For purchases from such suppliers, add three columns:

IRN, the 64-character hash from the IRP
Acknowledgement Number, 12-digit IRP confirmation number
Acknowledgement Date, timestamp of IRP registration

These columns are your verification trail. An invoice without a valid IRN from a covered supplier is a red flag before you even attempt 2B reconciliation.

GSTR-2B Reconciliation Column

Add a 2B Status column with four allowed values, Matched, Mismatch, Missing, Not Applicable, RCM or Import. Populate it monthly after downloading your GSTR-2B JSON or Excel from the GST portal. This single column drives your ITC availment decision each period.

Worked Example Row

Supplier, ABC Traders, GSTIN 27ABCDE1234F1Z5, Maharashtra. Invoice INV-2025-456 dated 15 July 2026. Taxable value ₹1,00,000. IGST ₹18,000, inter-state supply, your GSTIN is in Delhi, POS is Delhi. IRN, the 64-character hash. 2B Status, Matched. ITC to avail in July 2026 GSTR-3B, ₹18,000.

How To Build The Excel Template With GST Validations

The template is only as good as the rules that prevent bad data from entering. Three categories of validation eliminate most reconciliation failures, GSTIN format, duplicate invoice detection, and tax split logic.

GSTIN Structure Validation

A GSTIN is exactly 15 characters. Digits 1–2 are the state code, digits 3–12 are the supplier PAN structure, digit 13 is the entity number, digit 14 is Z, digit 15 is a checksum.

In Excel, apply this Data Validation formula to your GSTIN column:

=AND(LEN(A2)=15, ISNUMBER(VALUE(LEFT(A2,2))), VALUE(LEFT(A2,2))>=1, VALUE(LEFT(A2,2))<=38)

This catches obvious length and state-code errors instantly. For PAN structure within GSTIN, add checks, MID(A2,3,5) should be all alpha, MID(A2,8,4) all numeric. A GSTIN that fails these checks cannot belong to a registered supplier, and ITC on that invoice is at risk.

Duplicate Invoice Detection

Duplicate invoices cost money twice, once as a double payment and once as wrongly availed duplicate ITC. In a helper column, use:

=COUNTIFS($B$2:$B2,B2,$C$2:$C2,C2)

where column B is Supplier GSTIN and column C is Invoice Number. Any value greater than 1 flags a duplicate. Do not post duplicates to Tally until resolved.

Tax Split Logic

The CGST, SGST vs IGST split depends on whether the Place of Supply state matches your company's registration state. If POS state equals your state, CGST equals taxable value multiplied by rate divided by two, SGST equals the same. If POS state differs, IGST equals taxable value multiplied by rate. In Excel:

=IF(H2=your_state_code, F2*rate/2, 0) [CGST and SGST]
=IF(H2<>your_state_code, F2*rate, 0) [IGST]

Replace your_state_code with a named cell holding your state's two-digit code. This prevents the most common entry error, posting CGST, SGST on an inter-state supply, which creates an incorrect ITC split and a GSTR-3B mismatch.

Import-Ready CSV Structure

Dates in YYYY-MM-DD
Amounts with two decimals, no comma separators
GSTIN in uppercase
Blank cells as empty strings, not N or A
One row per document, credit notes and debit notes as separate rows with negative amounts for credit notes

Where Does A Manual Purchase Register Format Break Down?

The Time And Error Problem

Manual invoice data entry across accounting contexts runs at roughly 5 to 15 minutes per invoice including matching, classification, and filing. At 500 invoices a month, that is 40 to 125 person-hours before any reconciliation work begins. Error rates on manual entry run at 0.5 percent to 3 percent of records. Each erroneous row in a GST context is a potential ITC issue, not just an accounting correction.

The GSTR-2B Drift Problem

A manual register captures invoices as vendors send them, GSTR-2B captures what suppliers actually filed. These diverge for predictable reasons, vendors send invoices in one period but file GSTR-1 in the next, QRMP suppliers file quarterly, IFF uploads by QRMP suppliers appear in 2B later. Under Section 16(2)(aa) of the CGST Act, ITC is blocked until 2B reflects the invoice.

The RCM And Import Blind Spot

RCM purchases never appear in GSTR-2B. You pay the tax, self-invoice under Section 31(3)(f) of the CGST Act, and avail ITC separately in GSTR-3B Table 4A(2). Imports via BoE flow into 2B Table 4A(1) from ICEGATE, but only after customs data syncs. A register without explicit RCM and Import flags creates reconciliation noise every month.

The Cost Of Getting It Wrong

If ITC is availed on an invoice not in GSTR-2B and the error surfaces in audit, Section 50(3) of the CGST Act charges 18 percent per annum interest from the date of utilisation. Under Section 73, reversing before a show-cause notice means no penalty. Under Section 74, post-order penalties can reach 100 percent of tax due. One month of carelessly availed ITC on ₹10 lakh of purchases at 18 percent GST means ₹1.8 lakh of ITC at risk, plus 18 percent interest.

How To Reconcile With GSTR-2B, Statuses And Field-Level Checks

Reconciliation is a monthly match between your purchase register rows and GSTR-2B data, field by field. Five fields must match exactly, Supplier GSTIN, document number, document date, taxable value, and tax amounts.

The Four Reconciliation Statuses

Matched — Meaning, all five keys align with 2B, ITC Action, avail ITC in current GSTR-3B
Mismatch — Meaning, row exists in both but a key differs, ITC Action, hold ITC, resolve with supplier
Missing In 2B — Meaning, in your register, absent from 2B, ITC Action, hold ITC, follow up on GSTR-1 filing
Not Applicable — Meaning, RCM or import row, ITC Action, handle via GSTR-3B, no 2B match expected

How Credit Notes And Debit Notes Flow Through 2B

When a supplier issues a credit note, it flows into your GSTR-2B under the credit or debit notes section, and a credit note reduces your available ITC. If you already availed ITC on the original invoice, reverse it in the period the credit note appears in 2B. The supplier's time limit for credit notes is the earlier of 30 November of the succeeding financial year or the date of filing the annual return, Section 34(2) of the CGST Act. Debit notes increase your available ITC and follow the same ITC time limit under Section 16(4) of the CGST Act.

In your register, maintain separate rows for credit notes and debit notes with a Document Type column, Invoice, Credit Note, Debit Note, so your reconciliation handles sign correctly. A credit note row should carry negative taxable value and negative tax amounts.

Worked Mismatch Example

Your register shows, Supplier GSTIN 29PQRST5678G1Z3, Invoice INV-100, Date 10 August 2026, Taxable Value ₹50,000, IGST ₹9,000. GSTR-2B shows the same GSTIN and invoice number but taxable value ₹45,000 and IGST ₹8,100. Status, Mismatch. Action, contact the supplier, confirm whether they filed the invoice with ₹45,000 in GSTR-1. If yes, the supplier must amend GSTR-1 or you accept the lower value. Avail only ₹8,100 ITC until the discrepancy resolves.

GSTR-1 Timing And Your 2B Window

Monthly filers must file GSTR-1 by the 11th of the following month, their invoices appear in your 2B by the 12th. QRMP suppliers using IFF upload invoices by the 13th, those appear in 2B by the 14th. QRMP suppliers who skip IFF and file quarterly, invoices from the first two months arrive in your 2B only after the quarter. Expect Missing status until the filing date.

How To Post To Tally With Bill-Wise Allocation And Avoid Reversals

Enable Bill-Wise Details In Tally Prime

Company level, Gateway of Tally, F11 Features, Accounting Features, Maintain Bill-wise Details, Yes.
Ledger level, Gateway of Tally, Alter, Ledger, select the supplier, Maintain Bill-wise Details, Yes.

Without both settings active, Tally will not prompt for reference types, and purchases post On Account, making your creditor ageing unreliable.

Reference Types And When To Use Each

New Reference — When to use, every new purchase invoice, behaviour, creates an open bill in the creditor ledger with a unique reference
Against Reference — When to use, vendor payment, behaviour, links payment to specific open bills, closes them
Advance — When to use, advance payment before invoice, behaviour, records amount against party, no specific bill linked yet
On Account — When to use, avoid if possible, behaviour, posts amount to party with no bill linkage, breaks ageing

New Reference example, posting invoice INV-ABC-456 for ₹1,18,000, ₹1,00,000 plus ₹18,000 IGST, enter INV-ABC-456 as the reference and ₹1,18,000 as the amount. Against Reference example, making a ₹59,000 partial payment against INV-ABC-456, allocate ₹59,000 to that bill. Advance example, pay ₹20,000 in advance, later link it against the invoice.

Vendor Master Fields That Prevent Tally Tax Ledger Errors

Before posting any purchase, verify GSTIN, State, and GST Registration Type on the creditor ledger. Tally uses supplier state vs your company state to auto-select IGST vs CGST and SGST ledgers during voucher entry.

Importing Purchase Vouchers Into Tally

Tally Prime import uses XML. Export a sample purchase voucher to XML to capture schema, map your CSV columns, convert with a script or Tally-compatible tool, and import via Gateway of Tally, Import, Vouchers. Create all ledger masters first. After import, check logs and spot-check vouchers for bill-wise accuracy.

FAQ

Does CBIC prescribe a mandatory purchase register format under GST?

No. CBIC and GSTN have not prescribed a specific format for the purchase register. However, Section 16(2) of the CGST Act, 2017 and Rule 36(2) of the CGST Rules effectively make certain fields mandatory to substantiate an ITC claim. In practice, any register that omits supplier GSTIN, invoice number, taxable value, or tax amounts cannot support an ITC defence. Many finance teams use AI Accountant to ensure these fields are enforced at the time of capture, so later reconciliation passes on the first attempt.

What is the document retention period for purchase records under GST?

Section 36(1) of the CGST Act, 2017 requires purchase records to be retained for 72 months from the due date of filing the annual return for that financial year. Under Section 36(2), if an appeal or revision is pending, retention extends to one year after final disposal. For example, for FY 2025–26, with a GSTR-9 due date of 31 December 2026, retain records until 31 December 2032.

How do I validate a 15-digit GSTIN in Excel without a macro?

Use a combination of LEN and MID functions in a Data Validation formula. A minimum check is =AND(LEN(A2)=15, ISNUMBER(VALUE(LEFT(A2,2)))). A stronger check adds PAN structure validation, EXACT(UPPER(MID(A2,3,5)),MID(A2,3,5)) and ISNUMBER(VALUE(MID(A2,8,4))). Apply as a Stop alert so invalid GSTINs cannot be entered. AI Accountant enforces GSTIN format at ingestion, and can auto-flag inactive GSTINs for AP teams.

What formula prevents the wrong CGST, SGST vs IGST split in Excel?

Define a named cell for your two-digit state code, for example 07 for Delhi. In IGST column use =IF(POS_State_Column<>MyStateCode, TaxableValue*TaxRate, 0). In CGST and SGST columns use =IF(POS_State_Column=MyStateCode, TaxableValue*TaxRate/2, 0). This ties the split to Place of Supply vs registration state under Section 8(1) of the IGST Act, 2017.

At what invoice volume should I move from manual Excel to an automated purchase register?

There is no universal cutoff, but at 300 plus invoices per month, manual entry typically consumes more than 25 person-hours before reconciliation, and error rates of 0.5 percent to 3 percent mean at least one to nine erroneous rows each month. At this volume, the error cost exceeds tooling cost. Below 100 invoices, a disciplined, validated Excel may be adequate. Teams often adopt AI Accountant between 200 and 400 invoices per month to get automated capture and 2B reconciliation.

What happens if a supplier files GSTR-1 late and my ITC is blocked for that month?

Under Section 16(2)(aa) of the CGST Act, ITC can only be availed when the invoice appears in GSTR-2B. If a supplier files after the 2B cut-off, the invoice will feature in the next 2B. You cannot avail that ITC in the current month, but it is not permanently lost, subject to the Section 16(4) time limit. AI Accountant can track such Missing status items and auto-move them to eligible months when they appear in 2B.

Can I avail ITC on an invoice that is in my purchase register but not in GSTR-2B?

No. Section 16(2)(aa) makes 2B reflection a prerequisite for ITC availment. Maintain supplier communication and documentary proof so that when the invoice surfaces in a later 2B, your deferred claim is supported. Automated reconciliations ensure such invoices are parked with a Missing status and excluded from GSTR-3B availment.

How do I handle a supplier credit note that reduces ITC I already availed?

When a credit note appears in your GSTR-2B, it reduces available ITC. If you availed ITC earlier, reverse it in GSTR-3B Table 4(B)(2) for the current month. Maintain a credit note row in your register with negative taxable and tax values, Document Type, Credit Note, and 2B Status, Matched. The supplier deadline is governed by Section 34(2) of the CGST Act.

How does the register treat purchases from unregistered vendors under RCM?

For Section 9(4) scenarios, issue a self-invoice under Section 31(3)(f) and pay GST under RCM. These never appear in GSTR-2B. In your register, set RCM flag to Y, record your self-invoice reference, report tax in GSTR-3B Table 3.1(d) and ITC in Table 4A(2), and mark 2B Status, Not Applicable. AI Accountant separates these flows so they do not pollute 2B exceptions.

What is the difference between New Reference and On Account in Tally bill-wise details?

New Reference creates a specific open bill in the creditor ledger, enabling direct payment matching with Against Reference and accurate ageing. On Account posts to the party without bill linkage, making ageing unreliable. Use On Account only when no invoice reference is available, and clear it promptly.

How do I correct a purchase voucher in Tally that was posted On Account instead of New Reference?

Alter the purchase voucher and change the bill-wise allocation from On Account to New Reference, entering the correct invoice reference and amount. If a payment exists, alter the payment voucher to link it Against the newly created reference. Re-check ageing and outstanding reports.

What is the difference between a purchase register format and GSTR-2B in GST?

A purchase register is your internal record of invoices, GSTR-2B is a static monthly statement populated from suppliers’ filings. Under Section 16(2)(aa), ITC is available only when both align, which is why the register must be designed for exact 2B matching of the five keys.

Can I use the same purchase register format for both goods and services purchases?

Yes, with one adjustment. For goods, keep HSN and quantity or UOM, for services, SAC and description. Maintain an HSN or SAC column and a Goods or Services flag. Both are subject to the same Section 16(2) ITC conditions.

What happens if I avail ITC in the wrong financial year and discover it during year-end reconciliation?

Section 16(4) caps ITC availment at the earlier of 30 November of the succeeding year or the annual return filing date. If claimed within this window, no issue, even if from a prior year. If after the deadline, reverse in GSTR-3B Table 4(B)(2) and pay 18 percent interest under Section 50(3) from utilisation date. Close the loop in your reconciliation before GSTR-9.

How do I handle an invoice in my purchase register that has a wrong GSTIN from the supplier?

An incorrect GSTIN breaks Section 16(2)(a) compliance, hold the ITC. Ask the supplier to amend GSTR-1 and reissue a corrected invoice. If the supplier is subject to e-invoicing, the IRN is tied to the GSTIN and must be corrected. Mark the row as Mismatch and exclude it from availment until corrected and appearing in 2B.

Does my purchase register need to separately track ITC eligible vs ineligible purchases?

Yes. Section 16(1) allows only business-use ITC, Section 17(5) blocks specific categories. Add an ITC Eligibility column with values, Eligible, Blocked, Exempt Supply, Non-Business Use. Only Eligible rows flow to GSTR-3B Table 4A, blocked credits are expensed.

What is the correct way to record a Bill of Entry for imports in the purchase register format?

Use the BoE number as document number and BoE date as invoice date. Supplier GSTIN is not applicable, capture assessable value, IGST paid on import, and Basic Customs Duty separately. Flag Transaction Type, Import, and 2B Status, Not Applicable. ITC on IGST paid at the port is available once goods are received, under the IGST framework.

What fields from the purchase register map to GSTR-3B for ITC reporting?

GSTR-3B Table 4 requires ITC Available, own use, ITC Available, imports and inward on RCM, ITC Reversed, Rule 42 or 43 and Section 17(5), and Net ITC Availed. Sum Matched rows by tax type for Table 4A(1) and Table 4A(2). Rows with Mismatch or Missing statuses are excluded. Blocked credits flow to Table 4(B)(1). Tools like AI Accountant automate this mapping to reduce manual errors.

What interest applies if ITC wrongly availed in one month is reversed two months later?

Interest runs at 18 percent per annum under Section 50(3) from the date the ineligible ITC was utilised to the date of reversal. For example, ₹1,00,000 utilised on 20 August and reversed on 20 October, interest equals ₹1,00,000 × 18 percent × 61/365. If reversed before a show-cause notice under Section 73(6), no penalty applies.