Found an old receipt? Check the unclaimed GST credit

A supplier invoice found in an old email account is a reason to check the records before adding a transaction. It is a focused follow-up to an end-of-year records check, rather than a reason to enter the whole purchase again.

Search the accounts before entering anything

Search supplier names, invoice number, gross amount and payment reference. Try earlier accounting systems and the records held by your bookkeeper. A purchase may already have been recorded from a replacement invoice, a supplier statement or an approved alternative document.

Then check the GST transaction reports supporting lodged BAS returns. The expense appearing in the ledger doesn't prove the credit was claimed; equally, the invoice attachment being absent doesn't prove it was missed. Follow the actual tax amount and reporting period.

If the purchase was already claimed, attach the recovered document to the existing record and close the enquiry. Don't create a second bill to give the new attachment somewhere to live.

Establish the credit and its original timing

Check purchaser identity, GST registration, business use, supplier tax treatment and invoice validity. Read the actual GST amount. A receipt for an input-taxed or GST-free purchase doesn't produce a credit merely because it is a business cost.

Record when a credit could first have been claimed under the relevant cash or non-cash rules. The ATO's GST-credit time-limit guidance explains that the ordinary four-year clock is tied to the due date of the first relevant BAS, disregarding the tax-invoice holding requirement for that calculation. It isn't generally four years from the day you rediscover the invoice.

Keep a recovered-receipt register

Check	Fictional example	Record to retain
Document recovered	Invoice R-17, $880 including $80 GST	Supplier invoice and purchaser identity
Prior entry search	Expense exists, credit held pending invoice	Ledger ID and old missing-document register
Prior BAS search	No $80 claim located in the reviewed reports	Periods and reports searched; agent confirmation
Entitlement review	Wholly business and creditable under example assumptions	Document and use check
Time-limit review	Agent identifies original attribution period and due date	Calculated expiry and actual planned lodgement date
Final resolution	Claim once in the eligible BAS, or record why unavailable	BAS reference, amount and reviewer decision

The table assumes no earlier claim. It intentionally requires the actual deadline calculation rather than supplying an expiry from the receipt date. Original ASBG worksheet; all example figures are fictional.

A useful duplicate key is supplier ABN plus invoice number, with amount and date as checks. Keep variations in invoice numbers visible: "R17" and "R-17" might be the same document. Search by amount too where a supplier has reissued an invoice under a new number.

Use the right reporting route

The ATO says claiming a previously unclaimed GST credit on a later BAS is not itself a GST error. A later claim can be available within the relevant limit when the conditions are met. That differs from correcting a duplicate credit or a wrongly reported GST amount.

Don't apply the debit-error dollar threshold to decide whether an otherwise valid missed credit can be claimed. Nor should you assume that revising an old BAS will rescue a credit after its separate time limit expires. The period-of-review guidance distinguishes assessment review from credit entitlement limits.

If the deadline is close, contact the agent promptly and identify the actual lodgement action required. A draft in the software, an email to the accountant or a request for a ruling isn't the same as including the credit in an assessment. Specific exceptions exist and should be checked on their terms.

Close the record so it cannot be claimed again

Once resolved, record the final GST amount and BAS period on the register. Cross-reference the ledger entry and keep the recovered invoice attached. If no credit is available, retain the reason rather than deleting the evidence.

Review the cause too. If supplier invoices keep going to an unused email address, fix that workflow. The record-keeping guide helps turn this one-off recovery into a more reliable monthly routine.

Continue with the next question

• Missing tax invoice? Check the evidence before claiming GST
• Correct a GST mistake: later BAS or original revision?

Key takeaways

• Search existing entries and lodged GST reports before creating a bill.
• Calculate the credit deadline from the applicable original BAS timing.
• Record the final claim reference or the reason no claim was made.

Where to get help

Use the ATO GST-credit guidance and a registered agent for time-limit questions or exceptions. The Bookkeeping and BAS hub connects the purchase and reporting checks.