Businesses in Singapore may claim GST input tax based on either the tax invoice date or the date a document is posted into their accounting system, provided specific conditions are met, according to guidance from the Inland Revenue Authority of Singapore (IRAS).
Singapore’s Inland Revenue Authority of Singapore (IRAS) has clarified the rules for determining the accounting period in which businesses may claim GST input tax, including the circumstances under which claims can be based on the date of a tax invoice or the date a document is posted into an accounting system.
The guidance also explains when input tax may be claimed before payment to a supplier and outlines the adjustments required where a business fails to pay for a purchase within 12 months of the payment due date.
Claiming based on document date
Under the standard method, input tax is claimed in the accounting period corresponding to the date shown on the tax invoice or import permit.
For example, if a tax invoice is dated 22 February 2025, the input tax should be claimed in the accounting period covering 1 January 2025 to 31 March 2025.
Claiming based on posting or processing date
Businesses may alternatively claim input tax based on the date the document is posted or processed in their accounting system. This approach is permitted only if three conditions are met.
First, the business must apply the method consistently across all GST returns. Second, the original tax invoices or import permits must be in its possession at the time the claim is made. Third, adequate internal controls must be in place to ensure that the same purchase is not claimed more than once.
Claims before sales or payment
IRAS clarified that businesses do not need to wait until a related sale is made before claiming input tax. Input tax may be claimed even if the corresponding output tax is not reported in the same accounting period.
Businesses are also allowed to claim input tax before payment is made to the supplier, provided all other requirements for claiming input tax have been satisfied.
Repayment for unpaid purchases
Where a business has claimed input tax but fails to pay its supplier within 12 months of the payment due date, the input tax must be repaid to IRAS.
The repayment is made through adjustments in the GST F5 return for the accounting period in which the 12-month threshold is reached.
Businesses must reduce the purchase value reported in Box 5 (Total value of taxable purchases) and reduce the GST amount reported in Box 7 (Input tax and refunds claimed) by the corresponding amount previously claimed.
The repayment requirement is intended to ensure that input tax relief is not retained indefinitely on purchases that remain unpaid beyond the prescribed period.
