Tax Invoice Requirements Singapore: What a GST Invoice Must Show

What a GST tax invoice must show

IRAS lists the required details on its invoicing customers page/basics-of-gst/invoicing-price-display-and-record-keeping/invoicing-customers). Use this as a checklist against your current template.

If one invoice covers standard-rated, zero-rated or exempt items together, the gross amount for each type must be shown separately. If your UEN and GST registration number are the same, IRAS accepts formats such as 'GST Reg No.: 123456789A'. If they differ, show the GST number, for example 'GST Reg No.: M21234567K'.

Invoicing in a foreign currency

You can bill in US dollars or another currency, but the three totals (excluding GST, GST, and including GST) must also be shown in Singapore dollars, using an exchange rate IRAS approves for GST purposes.

When you must issue a tax invoice (and when you need not)

The rules depend on who your customer is and what you sell.

IRAS's page on responsibilities of a GST-registered business/basics-of-gst/responsibilities-of-a-gst-registered-business) also says retail sales to end consumers can use a serially printed receipt for each sale.

Simplified tax invoices and receipts

For smaller sales, IRAS allows shorter documents. A simplified tax invoice can be used when the total payable, including GST, does not exceed S$1,000. It needs only:

1. your name, address and GST registration number;
2. date of issue;
3. an identifying number, such as an invoice number;
4. description of the goods or services;
5. total amount payable including GST;
6. a statement such as 'Price payable includes GST'.

A receipt for a non-GST-registered customer must be serially printed and show the date, your business name and GST registration number, the total including GST, and the words 'Price payable includes GST'. You must keep a duplicate.

Separately, if you are GST-registered, prices you display to the public (price tags, adverts, websites) must include GST, per IRAS's price display rules/basics-of-gst/invoicing-price-display-and-record-keeping/displaying-and-quoting-prices).

How to calculate and round GST on an invoice

IRAS accepts two methods when an invoice has several standard-rated items: work out 9% on each line and add them up, or add up the lines and apply 9% to the subtotal. The total can differ by a cent because of rounding. Either is fine, but pick one and use it consistently.

You may round the total GST to the nearest cent. For cash customers you may also round the total bill to the nearest 5 cents, as long as you consistently round up or consistently round down.

Accounting software handles this automatically once you choose the setting, which is one reason to avoid hand-made invoices in Word or Excel.

Credit notes: fixing mistakes and refunds

Issue a credit note, not a new invoice with a negative amount, when you correct a mistake or give a customer credit. IRAS lists the usual reasons: wrong GST treatment, goods or services not supplied, charges waived, sub-standard goods accepted at a lower price, goods returned, or a discount on a past sale.

• identifying number and date of issue;
• your name, address and GST registration number;
• the customer's name and address;
• the reason for the credit, for example 'returned goods';
• description, quantity and amount credited for each item;
• total credited excluding GST, the GST rate and amount, and total including GST.

Show the number and date of the original tax invoice on the credit note. Adjust your GST return for the period in which the credit note is issued, unless it corrects a wrong GST treatment that needs a GST F7 correction. Your accountant will know which applies.

Record keeping and InvoiceNow

Keep tax invoices you issue and those you receive for at least 5 years. You do not submit them with your GST return, but IRAS can ask for them. Electronic records are acceptable without IRAS approval if they meet the conditions in IRAS's record-keeping guidance/basics-of-gst/invoicing-price-display-and-record-keeping/keeping-records).

GST-registered businesses are also being phased into the GST InvoiceNow requirement, which sends invoice data to IRAS through the Peppol network. Businesses that registered voluntarily from 1 April 2026 already have to comply; existing registrants are being phased in from 2028. Our InvoiceNow set-up guide explains the dates and steps.

Setting up compliant templates in Xero, QuickBooks and Shopify

Most problems come from a template set up once and never checked. Work through these steps in whichever tool you use.

1. 1

   Add your GST registration number to the organisation settings

   In Xero and QuickBooks, enter it in the business or tax settings so it prints on every document.

2. 2

   Change the document title to 'Tax Invoice'

   In Xero this is part of the invoice branding theme; in QuickBooks, in the custom form style. Keep a separate theme without GST wording if you also bill as a non-registered entity.

3. 3

   Show the GST rate and the three totals

   Make sure the template prints the rate column, subtotal excluding GST, total GST and total including GST.

4. 4

   Check that the customer's address prints

   Full tax invoices need the customer's name and address; fill both in on each contact.

5. 5

   Fix Shopify order emails

   Shopify's default order confirmation is not a tax invoice. Add your GST number and 'Price payable includes GST' to the notification template, or use an invoice app. Our Shopify GST guide walks through it.

6. 6

   Test with a real invoice

   Issue a sample invoice and credit note, then tick them against the 12-field checklist above.

If you are still choosing software, our Xero vs QuickBooks comparison covers GST filing and InvoiceNow support.

Do it yourself or get help?

Fixing a template is a one-hour job if you know where the settings are. Getting payments, invoices, credit notes and bank feeds to reconcile automatically takes longer. This guide is general information, not tax advice; check special cases such as customer accounting for mobile phones and software with your accountant.

Xero / QuickBooks Integration (S$390) brands your invoice and receipt templates, connects Stripe, HitPay or Shopify and your bank feed, and sets up payment reminders. InvoiceNow (Peppol) Setup (S$190) registers your Peppol ID and sends a test e-invoice from your software.