GST Compliance Checklist for Small Businesses

Due dates may be extended for a particular tax period or class of taxpayers. Confirm the applicable date on the GST Portal before filing.

1. Confirm Registration and Scheme Eligibility

Check whether GST registration is required

GST registration depends on aggregate turnover, the nature of supplies and the states or Union Territories in which the business operates.

Aggregate turnover is calculated on a PAN basis across India. A business cannot apply the threshold separately to each branch or GSTIN . Compulsory-registration provisions and specific exemptions may also change the result.

Consider simplified registration under Rule 14A

An applicant who self-assesses that the total output tax liability on supplies to registered persons will not exceed ₹2.5 lakh per month may opt for simplified registration under Rule 14A. This limit includes CGST, SGST or UTGST, IGST and compensation cess. The applicant must select the relevant option in Form GST REG-01 and complete the prescribed Aadhaar authentication.

Subject to successful Aadhaar authentication, registration is granted electronically within three working days from the generation of the Application Reference Number.

Choose the appropriate GST scheme

Filing frequency should not be the only consideration. Customer ITC requirements, inter-state supplies, e-commerce transactions, expected turnover and cash flow can make one scheme more suitable than another.

Composition taxpayers may sell goods through an e-commerce operator, provided the supplies are made within the state and the prescribed conditions are met. Inter-state supplies through the operator are not permitted.

Complete post-registration requirements

Display the registration certificate at the principal and additional places of business and show the GSTIN on the name board. Ensure that all operating locations, authorised signatories, contact details, bank accounts and management information are updated where required.

An eligible exporter or SEZ supplier should furnish a Letter of Undertaking before making zero-rated supplies without payment of IGST. The LUT remains valid for the financial year in which it is furnished. There is no universal 31 March deadline. Although delayed filing may be accepted retrospectively in some cases, businesses should furnish the LUT before making such supplies rather than rely on post-facto approval.

2. Control Invoice and Transaction Data

Maintain accurate accounting masters

Accurate returns begin with accurate master data. Before invoicing, verify customer and supplier GSTINs, state codes, place of supply , HSN or SAC, GST rates, units, taxability, cess and reverse-charge treatment.

E-invoice and e-way bill applicability should also be mapped correctly. Do not select a tax rate only from an HSN or SAC number . Consider the complete tariff entry, relevant notification and any value, use or recipient conditions.

Apply current HSN reporting rules

For GSTR-1 Table 12, taxpayers with aggregate annual turnover (AATO) up to ₹5 crore generally report four-digit HSN codes, while taxpayers above ₹5 crore report six-digit codes.

From the May 2025 return period, HSN codes must be selected from the portal dropdown. Business-to-business (B2B) and business-to-consumer (B2C) supplies are reported through separate tabs. Table 13, which captures details of documents issued, is mandatory where outward supplies are reported.

Review the item master whenever a product, classification or tax rate changes. A correct HSN code linked to an outdated rate can still produce an incorrect invoice.

Check tax invoice particulars

A tax invoice should contain the particulars required under Rule 46, including the supplier’s name, address and GSTIN, a unique consecutive number , invoice date, recipient details, HSN or SAC, description, quantity, taxable value, GST rate and tax amount.

Place of supply, reverse-charge indication and signature or digital signature should also be included where applicable.

Different invoice series may be used for branches or transaction types, but each series must remain unique and traceable. Cancelled invoice numbers should be retained with the reason for cancellation and must not be reused.

Check e-invoice applicability

E-invoicing generally applies where aggregate annual turnover under the PAN exceeded ₹5 crore in any financial year from 2017-18 onwards, subject to notified exemptions.

For a covered document, report the invoice, credit note or debit note to an authorised Invoice Registration Portal (IRP) and obtain the Invoice Reference Number (IRN) and signed QR code. Confirm that the portal data matches the accounting entry and retain the acknowledgement with the document.

An IRN can normally be cancelled through the portal only within 24 hours. The e-invoice requirement continues to apply even if current turnover falls below ₹5 crore after the threshold was crossed in an earlier relevant year.

Apply the 30-day IRP reporting restriction

From 1 April 2025, taxpayers with AATO of ₹10 crore or more cannot report covered invoices, credit notes or debit notes to the IRP after 30 days from the document date.

A daily exception report can identify documents that have been created but have not received an IRN. Waiting until GSTR-1 preparation may leave insufficient time to correct them.

Check e-way bill requirements before movement

An e-way bill is generally required before goods move where the consignment value exceeds ₹50,000. Exemptions, mandatory cases and intrastate thresholds may differ.

Before dispatch, compare the invoice or delivery challan with the recipient GSTIN, place of supply, consignment value, HSN, quantity, transporter details and vehicle number. Where e-invoicing applies, the e-way bill data should also agree with the IRN-linked invoice.

3. Follow This Monthly GST Filing Checklist

Step 1: Close the sales register

Before preparing GSTR-1 , confirm that all sales invoices have been recorded and that missing or cancelled numbers are explained.

Review credit notes, debit notes, advances and adjustments. Classify taxable, exempt, nil-rated and non-GST supplies correctly and verify whether CGST and SGST or IGST has been applied based on the place of supply.

The sales register should then be matched with e-invoices and e-way bills. Investigate any document that appears in one system but not another.

Step 2: Prepare GSTR-1 or IFF

QRMP taxpayers may use the Invoice Furnishing Facility (IFF) during the first two months of the quarter when B2B invoices need to become visible to recipients earlier. Before filing, review document totals, HSN reporting, Table 13, and portal warnings. Correcting errors before submission is more reliable than depending on a later amendment.

Step 3: Use GSTR-1A for same-period corrections

GSTR-1A is an optional facility available after GSTR-1 has been filed and before GSTR-3B is filed for the same tax period. It can normally be filed once for that period.

Before GSTR-1A was introduced for the August 2024 return period, eligible errors generally had to be corrected through a later GSTR-1 amendment. GSTR-1A now allows eligible additions and amendments before the corresponding GSTR-3B is filed, with the corrected values flowing into GSTR-3B.

A filed GSTR-3B cannot be revised. Where an error originates in outward-supply reporting, correcting the source through GSTR-1A is generally more appropriate than changing only the GSTR-3B value.

Step 4: Review IMS

The Invoice Management System (IMS) was introduced from the October 2024 tax period. Before this, recipients primarily reviewed supplier-reported ITC through GSTR-2B. IMS added document -level options to accept, reject, or keep eligible records pending on the GST Portal.

No action is not treated as rejection. However, unfamiliar invoices, duplicate records, incorrect values, and disputed credit notes should still be investigated before GSTR-3B is filed.

Step 5: Reconcile GSTR-2B with the purchase register

The reconciliation should compare the supplier GSTIN, invoice number, date, taxable value, tax amounts, document type, and credit-note or debit-note references.

It should also confirm that the goods or services were received, the place of supply is correct, the credit is not blocked , and any required reversal has been identified. Payment status should be monitored for the 180-day rule.

Practical example: An invoice for ₹1,18,000 appears in IMS but is absent from the books. Verify the purchase order, goods-receipt record, supplier GSTIN and tax value. A genuine purchase should be booked and checked before ITC is claimed. A disputed or unrelated invoice should be rejected or kept pending, depending on the facts.

Step 6: Complete ITC checks

Appearance in IMS or GSTR-2B does not automatically make a credit eligible. The business must hold the prescribed document, receive the goods or services and satisfy the conditions under Sections 16 and 17 .

Blocked credits and reversals under Rules 37, 37A, 42 and 43 should be identified before filing. Temporary reversals that may later be reclaimed should be recorded separately from permanently ineligible credit.

ITC relating to an invoice or debit note is generally subject to the earlier of 30 November following the financial year or the date on which the relevant annual return is filed.

Step 7: Prepare and file GSTR-3B

Compare outward liability with GSTR-1 and GSTR-1A, and match ITC with the approved purchase reconciliation. Record reverse-charge liability , review reversals and reclaims, and confirm the electronic cash, credit and liability ledger balances.

Check interest and late fees before submission. From the January 2026 tax period, the GST Portal’s interest calculation considers the minimum electronic cash ledger balance while determining interest on delayed tax payment. System-computed interest in Table 5.1 cannot be reduced by editing it downward. After filing, retain the return, challans, acknowledgements and supporting reconciliation reports.

4. Additional Checks for QRMP and Composition Taxpayers 

QRMP taxpayers

Review QRMP eligibility at the beginning of each quarter and continue reconciling outward supplies and ITC during months when no quarterly return is due. The scheme reduces return frequency but does not remove monthly tax payment or record review responsibilities. If eligibility is lost, move to monthly filing from the applicable quarter.

The scheme reduces return frequency but does not remove monthly tax payment or record-review responsibilities. If eligibility is lost, the taxpayer must move to monthly filing from the applicable quarter.

Composition taxpayers

Monitor turnover, inter-state supplies, e-commerce transactions and other restricted activities throughout the year. If the eligibility conditions are no longer met, withdraw from the scheme and move to regular compliance from the applicable date. The CMP-08 and GSTR-4 due dates are listed in the compliance calendar above.

5. Complete the Annual GST Review

Reconcile the financial year

The annual review should compare turnover in the financial statements with the sales register, GSTR-1 and GSTR-3B. ITC in GSTR-3B should be matched with the purchase register and GSTR-2B .

Also review electronic ledgers, e-invoices, e-way bills, credit notes, debit notes, reverse-charge transactions, exempt supplies, zero-rated supplies, HSN summaries and branch-level records.

Annual-return disclosure does not automatically correct an error in a periodic return. Use the legally available amendment, payment or disclosure route for the type of error involved.

Check GSTR-9 and GSTR-9C applicability

From FY 2024-25 onwards, registered persons with aggregate turnover up to ₹2 crore are exempt from filing GSTR-9 under Notification No. 15/2025-Central Tax, subject to the notification. A self-certified GSTR-9C is generally required where aggregate turnover exceeds ₹5 crore and is filed with GSTR-9 by the applicable annual due date.

Even where GSTR-9 is not required, complete an internal annual reconciliation. The exemption does not remove bookkeeping, tax-payment, ITC or record-retention requirements.

Clear old return backlogs

Specified returns and statements under Sections 37, 39, 44 and 52 cannot generally be furnished more than three years after their original due date. The Government may permit specified exceptions through notification.

An old return is therefore not only a late-fee issue. If it remains unresolved, filing may eventually become time-barred.

Retain GST records

GST accounts and records must generally be retained for 72 months from the due date for filing the annual return for the relevant financial year.

Keep them for longer where an appeal, revision, investigation or other proceeding remains pending.

Period-specific extensions, waivers and amnesty notifications may change the amount for a particular tax period. Confirm the relevant notification before calculating an old liability.

Bring GST Workflows Into One System

BUSY accounting software connects GST invoicing, accounting, inventory, e-invoice and e-way bill generation, GST return-related reports and GSTR reconciliation. This reduces repeated data entry and makes it easier to trace figures from invoices to returns.

More than 6,00,000 businesses use BUSY. Software can make the GST checklist easier to manage, but the business and its adviser should still review classification, ITC eligibility, exceptions and the final return.

Conclusion

A useful GST compliance checklist should follow the same sequence as the underlying records: register correctly, create accurate invoices, reconcile outward and inward supplies, file the correct returns and retain supporting evidence.

The strongest control is a documented monthly close in which the sales register, purchase register, IMS, GSTR-2B, e-invoices, e-way bills and GSTR-3B agree before filing. This makes errors easier to correct and differences easier to explain during scrutiny or annual reconciliation.