Singapore tax invoices, clear and complete
Choose Singapore once and WhizInvoice sets up dollars, GST at 9%, your GST registration number and the Tax invoice title. Before you rely on any invoicing tool, check where your business sits in the IRAS InvoiceNow timeline.
When a tax invoice is needed
A GST-registered business must issue a tax invoice when its customer is also GST registered, generally within 30 days of the time of supply, because the customer needs it to claim input tax. You do not need one for zero-rated, exempt or deemed supplies, or for customers who are not GST registered, where a receipt can be issued instead.
Registration is compulsory once your taxable turnover for a calendar year exceeds S$1 million, or when you can reasonably expect it to exceed S$1 million over the next 12 months. Register late and you must account for GST on your past sales, even though you never collected it from customers.
Singapore GST at a glance
- GST rate
- 9%
- Registration threshold
- Taxable turnover over S$1 million in a calendar year, or reasonably expected over the next 12 months.
- Full tax invoice
- The words Tax Invoice, your name and address, GST registration number, invoice date and number, the customer’s name and address, a description, the GST rate, the total excluding GST, the total GST and the total including GST. Exempt and zero-rated supplies are stated separately.
- Simplified tax invoice
- Allowed when the total including GST is S$1,000 or less: your name, address and GST registration number, the date, an invoice number, a description, the total including GST and a statement such as price payable includes GST.
- Receipts
- For customers who are not GST registered: serially numbered and dated, with your business name, GST registration number, the total including GST and the words Price payable includes GST.
- When to issue
- Generally within 30 days of the time of supply. Keep copies for at least 5 years.
- Tax number label
- GST Reg. No., which is often the same as your UEN
- Currency
- Singapore dollar, SGD ($)
- Date format
- DD/MM/YYYY
- Paper size
- A4
- E-invoicing
- The GST InvoiceNow Requirement is being phased in: new voluntary registrants from 1 April 2026, new compulsory registrants from 1 April 2028, and existing registrants between 1 April 2028 and 1 April 2031 according to their annual supplies.
Source: Inland Revenue Authority of Singapore (iras.gov.sg) pages on invoicing customers, GST registration and the GST InvoiceNow Requirement, checked October 2026.
How WhizInvoice handles Singapore GST
Choose Singapore in Settings and these details are ready on every invoice. All of them can be adjusted.
The Singapore preset
Singapore dollars, GST at 9%, the GST Reg. No. label, the Tax invoice title, DD/MM/YYYY dates and A4 paper in one step.
Every total IRAS asks for
Each invoice shows the total before GST, the GST at 9% and the total including GST, with the customer’s name and address above.
One consistent GST method
GST is worked out on the invoice total for each rate and rounded to the cent, the same way every time, which is what IRAS asks of whichever method you use.
Not GST registered
Switch off GST registration and your documents are titled Invoice with no GST, until the day your registration starts.
PayNow and bank details
Put your PayNow UEN or bank account in your payment instructions, or add your own card payment link, and it prints on every invoice.
Records you can keep
Download every invoice and customer whenever you want, which helps you hold copies for the five years IRAS requires.
Aircon servicing for a registered customer
Quarterly aircon servicing for a GST-registered company. The customer will claim the GST, so this is a full tax invoice with every detail on it.
Example only, with a fictional business and customer. Your invoices use your own details, tax settings and design.
| Description | Qty | Rate | Amount |
|---|---|---|---|
| Aircon general servicing, ceiling cassette unit | 8 | $45.00 | $360.00 |
| Chemical wash, wall mounted unit | 2 | $90.00 | $180.00 |
| Refrigerant top up, one system | 1 | $120.00 | $120.00 |
Rounding and cash payments
IRAS lets you work out GST in either of two ways when an invoice has several standard-rated items: apply 9% to each item and add the results, or apply 9% to the total of the items. The answers can differ by a cent, which is fine, as long as you stick with one method.
You may also round the total bill to the nearest 5 cents to make cash payments easier. Whether you round up or down is your choice, but the choice has to be applied consistently.
Good to know
Do I need to issue a tax invoice for every sale?
Only when your customer is GST registered. For customers who are not registered you can issue a receipt instead, and you must still issue one if they ask.
When can I use a simplified tax invoice?
When the total amount payable, including GST, is S$1,000 or less. It needs fewer details but must still show your GST registration number and a statement that the price includes GST.
Is my GST registration number the same as my UEN?
Often it is. IRAS shows examples of both cases, where the UEN doubles as the GST number and where a separate GST registration number has been issued.
Does the InvoiceNow requirement apply to me?
It applies to new voluntary registrants from 1 April 2026 and to new compulsory registrants from 1 April 2028. Existing registrants join between April 2028 and April 2031 according to their annual supplies, and IRAS has been notifying them of their dates since mid-2026.
Can I round invoice totals to 5 cents?
Yes. IRAS allows you to round the total bill to the nearest 5 cents for cash payments, as long as you round consistently.
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