What are the Singapore GST charges on the Horizons Invoice?



Modified on: Tue, 7 Oct, 2025 at 9:51 PM

TABLE OF CONTENTS



This article explains how the “SGD Equivalence” is calculated on your tax invoice and its specific purpose, as well as answers to the most frequent questions about this figure. 


What is SGD Equivalence?

The “SGD Equivalence” is the Singapore Dollar (SGD) value shown on your invoice, converted from the original invoiced currency. This figure is provided solely for the calculation of Goods and Services Tax (GST), as required by the Inland Revenue Authority of Singapore (IRAS). Horizons’ GST registration number is 202117926G, and we are required by IRAS to apply GST from the effective registration date.


How is the SGD Equivalence Calculated?

  • Official Exchange Rate Source:
    The SGD Equivalence is determined using the exchange rate published by XE.com, which is the IRAS-designated source for tax reporting.
  • Applicable Date:
    In accordance with IRAS guidelines and our internal policy, the exchange rate used is the average rate from the second-to-last working day of the month preceding the invoice date.
  • Monthly Update Process:
    On the last working day of each month, our finance team retrieves the relevant exchange rates from     XE.com for all billing currencies, specifically referencing the second-to-last working day of the previous month. This process is documented and audited to ensure full traceability and compliance.


What is the SGD Equivalence Used For?

  • GST Calculation Only:
    The SGD Equivalence is used exclusively to calculate the GST value on your invoice, as required by Singaporean tax authorities.
  • No Impact on Invoice Amount:
    This figure does not affect the total amount payable, which remains in the original invoiced currency unless otherwise agreed.
  • Not for Payment or Settlement:
    The SGD Equivalence is not intended for use in payment, settlement, or any other accounting purpose outside of GST calculation.


Example

If your invoice is issued in USD and dated in April, the SGD Equivalence will be calculated using the XE.com exchange rate from the second-to-last working day of March.


SGD Equivalence = GST Amount in USD × XE.com SGD/USD rate (as of the second-to-last working day of the previous month)


This value is then used solely to determine the GST amount on your invoice.


FAQ: SGD Equivalence on Your Tax Invoice

  1. What is “SGD Equivalence” on my invoice?
    SGD Equivalence is the Singapore Dollar (SGD) value shown on your invoice, converted from the original invoiced currency. This figure is provided solely for the calculation of Goods and Services Tax (GST), as required by the Inland Revenue Authority of Singapore (IRAS).
  1. How is the SGD Equivalence calculated?
    The SGD Equivalence is calculated using the exchange rate published by https://www.xe.com/. Specifically, we use the average exchange rate from the second-to-last working day of the month preceding your invoice date, in line with IRAS guidelines.
  1. Why is the SGD Equivalence shown on my invoice?
    This value is required by Singaporean tax authorities to accurately calculate and report GST on invoices issued in foreign currencies. It ensures full compliance with IRAS regulations.
  1. Does the SGD Equivalence affect the amount I need to pay?
    No. The amount payable remains in the original invoiced currency, unless otherwise agreed. The SGD Equivalence is for GST calculation and reporting purposes only.
  1. Can I use the SGD Equivalence for payment or accounting?
    No. The SGD Equivalence is not intended for use in payment, settlement, or any other accounting purpose outside of GST calculation.

  1. Where can I find the exchange rate used for my invoice?

    If you would like to know the specific exchange rate applied, please contact our support team or your Horizons account manager. We will be happy to provide the relevant XE.com reference.

  1. What if my invoice is dated, for example, in April?

    For an invoice dated in April, the SGD Equivalence will be calculated using the XE.com exchange rate from the second-to-last working day of March.

  2. Can You Recover the GST?

    If your company is GST-registered in Singapore, you may be able to claim back the GST through your regular tax filings. If you’re not registered, recovery usually isn’t possible. In either case, we recommend speaking with your tax advisor or visiting iras.gov.sg for guidance.

  3. What About Other Countries or Entities?

    This change only affects clients billed through Horizons Singapore. If you’re billed through a Horizons entity in another country, or in a different currency, the GST charge does not apply.

  4. What About Discounts or Credits?

    GST is applied to the net amount after any discounts, credits, or prepayments. If you have a custom billing arrangement, feel free to reach out and we’ll review it with you.

Important Notes

  • The SGD Equivalence is for tax reporting only and does not impact the amount due for payment.
  • Should you require further details on the exchange rate applied to your invoice, our support team will be pleased to assist.







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