Purpose and edition
The fourth edition was published on 30 January 2026. It explains the conversion rates GST-registered businesses may use to translate foreign-currency supplies into Singapore dollars for GST purposes. Paragraph 11 of the GST Act’s Third Schedule requires conversion at the rates applicable at the time of supply.
Market relevance and the daily-rate test
All five conditions in the guide must be met. First, the rate must reflect the Singapore money market at the time of supply; rates from Appendix A sources are administratively acceptable. Second, it must be the daily rate corresponding to that time, or a good approximation.
A daily rate may be a prevailing buying rate, selling rate or their average. The guide allows a rate from a specified day, such as the last working day of the previous month, or an average over a specified period, such as the previous month’s daily rates, where it provides a good approximation.
Updating and using a method consistently
Third, update the rate at least once every three months. Fourth, use it consistently for internal business reporting, accounting and GST purposes. Fifth, use the method consistently for at least one year from the end of the accounting period in which it was first adopted. The one-year period is therefore measured from that period end, rather than simply from the day of the first transaction.
Sources in Appendix A: banks and newspapers
The acceptable bank sources include Singapore full banks, wholesale banks, offshore banks and merchant banks. Locally circulated newspapers are another category; the guide names the Business Times, Straits Times, Financial Times and Lianhe Zaobao as examples.
Sources in Appendix A: agencies, central banks and online resources
The appendix names reputable agencies such as Bloomberg, Reuters and Oanda. It also accepts foreign central banks without exchange controls, giving the European Central Bank and Federal Reserve Bank of New York as examples.
Online resources such as Yahoo! Finance and xe.com are included. The appendix also explains that website rates are acceptable when based on the specified source categories, and gives Yahoo! Finance’s Reuters-based rates as an example. Monetary Authority of Singapore rates are a separate listed source, with its statistical exchange-rate page linked in the PDF.
When no prior approval is needed
A GST-registered business using an Appendix A source and satisfying all five conditions need not obtain the Comptroller’s approval for those rates. The concession depends on the source and conditions together; choosing a listed provider alone does not remove the consistency requirements.
Applying to use other in-house rates
If an in-house rate uses another source, or the method fails to satisfy all five conditions, seek written approval through myTax Mail. Explain how the proposed rates reflect the Singapore money market at the relevant supply time, with a comparison against Appendix A rates over two weeks, for example rates published by a local bank.
Identify the rate type, such as daily, buying, selling or an average of buying and selling rates. Confirm quarterly-or-more-frequent updating, consistent use across business reporting, accounting and GST, and use for at least one year from the end of the first accounting period. The guide says close approximations to Appendix A rates will generally be allowed; this is not automatic approval of a specific proposal.
Evidence and enquiries
Maintain sufficient supporting documents for the exchange rates used. Keep the books and records properly and make them available when IRAS needs verification or requests them.
The edition directs GST-registered businesses to myTax Mail for enquiries. Businesses that are not GST-registered can use the IRAS Contact Us path for general GST enquiries. It also lists the GST live-chat channel, operating from 8am to 5pm on weekdays in this edition.
Edition history
The first edition dates to 30 September 2013; its amendment entry records additions to the purpose and overview and revisions to rate approval, records and Appendix A. The 13 June 2017 edition added xe.com. The 26 November 2021 edition revised Appendix A and made editorial changes.
The cover and publication page identify this file as the fourth edition dated 30 January 2026, while the amendment table stops at the 2021 entry. The article retains that distinction instead of inventing an unlisted 2026 amendment.
Official source
This article independently explains the substantive contents of the official PDF, including the relevant conditions, procedures and annexes. The linked document remains the authoritative source for its original wording, and later changes should be checked separately.
Read the official PDF ↗