What Should a Singapore-Compliant Invoice Template Include in 2026? Required Fields, GST Format and a Free Checklist
A Singapore tax invoice missing even one mandatory field can stop a GST-registered customer from claiming input tax. IRAS is also phasing in InvoiceNow transmission of invoice data for GST-registered businesses through 2031. In this blog, we discuss the mandatory fields on a Singapore tax invoice. We explain when a simplified tax invoice is allowed. We also cover GST rates, foreign currency rules and InvoiceNow readiness in 2026.
What Must a Singapore Invoice Template Show in 2026?
A GST-registered business must include seven field groups, set out by IRAS, whenever it issues a full tax invoice.
According to IRAS, a tax invoice is the main document supporting an input tax claim. Missing even one mandatory field can make it non-compliant and leave your customer unable to claim GST credits. The seven required field groups are:
1. The words "Tax Invoice"
Place the label prominently, usually at the top of the document. A page headed simply 'Invoice' or 'Bill' does not satisfy the GST tax invoice format, regardless of what else it contains.
2. Supplier name, address and GST registration number
Your business name should match the Accounting and Corporate Regulatory Authority (ACRA) records, together with your principal place of business and the GST number assigned to you by IRAS.
3. Customer name and address
For business-to-business sales, use the customer's registered business name and principal address. IRAS does not require the customer's GST registration number on the invoice itself. Keep that number in your records for verification. Addressing a bill to an individual employee can prevent the customer from claiming input tax.
4. Invoice date and identifying number
Each tax invoice needs a unique, sequential number so IRAS can trace every document during an audit. The date of issue also determines which GST filing period the sale falls into.
5. Description of the goods or services supplied
The description must adequately identify the goods or services supplied. A broad service label is not automatically rejected, but it must still be clear enough to show what was actually delivered. Name the supply and include quantities and unit prices where relevant, so the customer and IRAS can see exactly what was billed.
6. Amounts, GST rate and totals
Your document needs to display the net value before GST, the percentage charged, the GST sum itself, and the final figure once GST is added. With GST at 9% since 1 January 2024, every figure on the template must be correct and arithmetically consistent.
7. Breakdown of exempt, zero-rated or other supplies
If a single invoice mixes standard-rated, zero-rated and exempt items, each category must be shown separately with its own subtotal and rate.
When Can You Use a Simplified Tax Invoice or a Receipt?
Once the GST-inclusive figure for a sale stays at or below S$1,000, a shorter format with fewer mandatory fields becomes available.
IRAS allows this reduced format for high-volume, low-value sales. A simplified tax invoice still needs the following:
- supplier's name, address and GST registration number
- date of issue and identifying number
- description of the goods or services
- total amount payable including GST
- a statement that the price includes GST
Whether a plain receipt is appropriate depends on your own GST registration status, not your customer's. A GST-registered business can still issue a simplified tax invoice for these small sales. A business that is not GST-registered should issue a plain receipt as proof of sale. Keep a duplicate for your own records.
Full Tax Invoice vs Simplified Tax Invoice in Singapore
| Requirement | Full tax invoice | Simplified tax invoice |
|---|---|---|
| "Tax Invoice" label | Required | Not required |
| Supplier name, address and GST number | Required | Required |
| Invoice date and identifying number | Required | Required |
| Customer name and address | Required | Not required |
| Description of goods or services | Required | Required |
| Amount excluding GST, GST rate and GST amount | Required | Not required |
| Total including GST and a "price includes GST" statement | Required | Required |
| Eligibility | Any supply, mandatory for GST-registered customers | Total payable (including GST) must not exceed S$1,000 |
How Does the IRAS Invoice Format Differ for GST-Registered and Non-Registered Businesses?
A GST invoice format for Singapore businesses applies only when you are actually registered. A non-registered business must not label any document a tax invoice.
GST-registered businesses follow one set of invoice rules. Non-registered businesses follow another.
1. GST-registered businesses
You charge GST according to how the law treats the sale. Standard-rated sales attract 9%. Where an item is zero-rated or exempt, it follows its own treatment and appears with its own subtotal on the document. Issue a compliant tax invoice within 30 days of the time of supply when your customer is GST-registered. Retain tax invoices issued and received for at least five years. You do not submit them with your GST return.
2. Non-GST-registered businesses
You charge no GST. Use an ordinary invoice format with:
- your name, contact details and Unique Entity Number (UEN)
- the customer's details
- an invoice number and date
- a description of the goods or services
- the total amount payable
Labelling such a document a tax invoice misrepresents your GST status. This can attract penalties under the Goods and Services Tax Act.
How Should a GST Invoice in Singapore Handle Rates, Currencies and Calculations?
A Singapore GST invoice must apply the correct rate and show consistent arithmetic. IRAS accepts two methods for computing the GST on a multi-item invoice:
- apply 9% to the value of each item and then sum the GST amounts
- apply 9% to the sum of the items' values
- Use the chosen method consistently.
- When you bill in a foreign currency, the GST amounts and totals on the tax invoice must be converted into Singapore dollars.
- Most modern cloud accounting systems, including AI Account, handle these calculations automatically. This keeps your figures consistent across every line.
1. Apply GST per line item
Calculate 9% on each line's value and add the GST amounts together. This suits invoices with discounts or mixed rates on individual lines.
2. Apply GST to the invoice total
Sum the pre-GST values first, then apply 9% once. This is simpler for wholly standard-rated invoices.
3. Convert foreign currency correctly
Where you invoice in USD, EUR or another currency, the GST-related figures on the tax invoice must be expressed in Singapore dollars, using a consistent conversion basis.
Singapore Invoice Compliance Checklist (2026)
| Check | Why it matters |
|---|---|
| Label reads "Tax Invoice" | A document labelled "Invoice" is not a valid tax invoice |
| GST registration number shown | Customers need it to claim input tax |
| GST rate shown as 9% | The rate has applied since 1 January 2024 |
| Issued within 30 days of the time of supply | Deadline for GST-registered customers |
| Amounts exclude GST, show GST, and include GST | IRAS expects internal consistency across the three figures |
| Tax invoices kept for at least five years | Record-keeping requirement under GST law |
| Not issued if you are not GST-registered | Issuing one misrepresents your GST status |
How Does InvoiceNow Fit into Singapore's Invoicing Landscape?
InvoiceNow is the national e-invoicing framework built on the PEPPOL network. It lets Singapore businesses send structured e-invoices directly between accounting systems, rather than by PDF or post. Completing these final steps makes every invoice template Singapore ready for what comes next:
- Check your GST registration route. Businesses that join the GST register voluntarily on or after 1 April 2026 will need to route their billing data to IRAS through an InvoiceNow-ready solution. Broader phases run through 2031 based on annual supplies.
- Enable e-invoicing in your accounting platform. Structured e-invoices flow straight from your system to your customer's, removing PDF and post from the workflow.
- Validate the transmitted fields. Confirm that your tax invoice fields carry through into each e-invoice automatically — supplier details, GST number, invoice date, unique number, description, rate and totals.
AI Account automates compliant tax invoicing, GST calculations, currency conversion and five-year record retention in one cloud platform. Contact our team to see it working on your documents.
Need an Invoice Template That Stays Compliant Automatically?
AI Account generates GST-compliant tax invoices, applies the correct 9% rate and retains records for the required five years.
