Singapore GST Tax Invoice: Requirements and Format

Quick answer: A Singapore GST tax invoice must show the words "Tax Invoice", your name, address and GST registration number, an invoice number and date, the customer's details, a description, the amount before GST, the 9% GST and the total. For totals of S$1,000 or less, a simplified tax invoice is allowed.

Singapore's Goods and Services Tax (GST) is administered by the Inland Revenue Authority of Singapore (IRAS). For GST-registered businesses, the tax invoice is the key document: it is how you show the GST you charged, and it is what your GST-registered customers rely on to claim input tax. A missing GST registration number or an unclear GST amount can delay payment or cause a claim to be disallowed.

This guide covers who issues a Singapore GST tax invoice, the full and simplified formats, receipts, foreign currency invoices, a worked example, and the InvoiceNow e-invoicing rollout. For a comparison with other countries, see our invoice requirements by country overview. This is general information, not tax advice; confirm the details with IRAS or a qualified tax adviser.

GST in Singapore at a glance

• Standard rate: 9% since January 1, 2024.
• Zero rate: 0% for qualifying exports of goods and international services.
• Exempt supplies: certain financial services, the sale and lease of residential property, and some precious metals for investment.
• Registration: generally compulsory once taxable turnover exceeds S$1 million in a calendar year, or is expected to in the next 12 months. Voluntary registration is allowed below that.
• Issuing deadline: a tax invoice is generally issued within 30 days of the time of supply.

GST works like VAT: registered businesses charge it on sales and claim back the GST on business purchases. If you are comparing systems, our guide to GST invoices explains how Singapore's rules sit alongside Australia, India and other GST countries.

Who must issue a Singapore GST tax invoice

Only a GST-registered business can issue a tax invoice and charge GST. If you are registered, you generally must issue a tax invoice to a GST-registered customer for a standard-rated supply. You do not need to issue one for zero-rated supplies, exempt supplies, deemed supplies, or sales to customers who are not GST registered, although you can still give those customers an ordinary invoice or a receipt.

If you are not GST registered, do not charge GST, do not show a GST registration number and do not title your document "Tax Invoice". A plain invoice from our free invoice generator is fine in that case.

Full vs simplified tax invoice: requirements table

IRAS recognizes two formats. The simplified version is meant for smaller sales, where the total including GST is S$1,000 or less.

Detail	Full tax invoice	Simplified tax invoice (S$1,000 or less)
The words "Tax Invoice"	Required	Not required
Supplier name, address and GST registration number	Required	Required
Invoice identifying number	Required	Required
Invoice date	Required	Required
Customer name and address	Required	Not required
Description of goods or services	Required	Required
Discount offered	Required where given	Not required
Total excluding GST	Required	Not required
GST rate and GST amount	Required (by rate, if mixed)	Not required
Total including GST	Required	Required
Statement that price includes GST	Not needed	Required, e.g. "Price Payable includes GST"

The S$1,000 limit is measured on the GST-inclusive total. A sale priced at S$950 before GST becomes S$1,035.50 with 9% GST, so it needs a full tax invoice. For business clients who will claim input tax, a full invoice is the safer default even below S$1,000.

Your GST registration number

Singapore GST registration numbers are usually the same as the business's Unique Entity Number (UEN), or a separate number starting with M for some entities. Print it exactly as it appears on your registration letter. Customers can check it on the IRAS register of GST-registered businesses. Our guide to the tax ID on an invoice shows where to place it in the header.

Sample Singapore GST tax invoice with the GST math

Here is a full tax invoice from a Singapore design agency to a GST-registered client.

Field	Example
Document title	Tax Invoice
Supplier	Harbour Line Design Pte. Ltd., 10 Anson Road, Singapore
GST registration number	201912345K
Customer	Orchid Retail Pte. Ltd., 1 Raffles Place, Singapore
Invoice number and date	HLD-2026-0318, 28 October 2026
Line 1	Brand identity design, fixed fee = S$4,000.00
Line 2	Packaging artwork, 10 hours at S$120.00 = S$1,200.00
Discount	Repeat-client discount = -S$200.00
Total excluding GST	S$5,000.00
GST at 9%	S$5,000.00 x 0.09 = S$450.00
Total including GST	S$5,450.00
Payment terms	30 days, PayNow or bank transfer

When a price includes GST, use the tax fraction. At 9%, GST is 9/109 of the inclusive price, so a S$1,090.00 inclusive price contains S$90.00 of GST. Our sales tax calculator handles both directions if you want to double-check.

Time of supply and the 30-day rule

The 30-day deadline runs from the time of supply, which for most standard-rated supplies is the earlier of the date you issue the invoice or the date you receive payment. That rule also decides which GST period the sale falls into. If a client pays a deposit before you invoice, the deposit generally triggers the time of supply for that amount, so issue a tax invoice for it promptly rather than waiting for the final bill.

For long projects, invoicing by milestone keeps GST reporting aligned with the documents your client holds. Agree the milestone dates in your contract, and give each stage its own invoice number so that your records reconcile cleanly against your GST return.

Discounts, disbursements and mixed supplies

Discounts given at the time of sale reduce the value on which GST is charged, so show the discount before calculating GST, as in the example above. If you pass on costs you paid on your client's behalf, such as government fees, check whether they are true disbursements, which can be billed without GST, or part of your own supply, which carries GST. Label them clearly either way.

Where one invoice mixes standard-rated, zero-rated and exempt items, show a separate total for each category and the GST for the standard-rated part only. That keeps the invoice easy for your client's accounts team to post and easy for you to defend in an IRAS review.

Receipts and sales to non-registered customers

For sales to customers who are not GST registered, such as consumers, you do not need to issue a tax invoice. Retailers commonly issue a receipt instead. A receipt for a GST-registered business generally shows your name, address and GST registration number, a receipt number and date, a description, the total payable including GST and a statement that the price includes GST. IRAS also allows a combined "Tax Invoice cum Receipt" in some cases. Check IRAS's current receipt rules, because the details differ slightly from a tax invoice.

Remember that GST-registered businesses must also display prices to consumers inclusive of GST. Your invoice should be consistent with the price you quoted.

Foreign currency tax invoices

You can invoice in US dollars, euros or another currency, but the GST amount and the total excluding GST should also be shown in Singapore dollars, converted using an exchange rate acceptable to IRAS, such as a published market rate. Note the rate and its date on the invoice. Our guide to foreign currency invoices shows a clean layout for dual-currency totals.

Services supplied to overseas customers may qualify for zero-rating as international services. In that case, show GST at 0% and keep evidence that the conditions are met. Our explainer on zero-rated vs exempt supplies covers the difference.

Credit notes

If you reduce a price or accept a return after issuing a tax invoice, issue a credit note that refers to the original invoice, shows the reduction in value and GST, and states the reason. Do not reissue the original invoice with changed figures. See our credit note guide for a template.

InvoiceNow: Singapore's e-invoicing requirement

Singapore's national e-invoicing network, InvoiceNow, is built on Peppol, the same standard used in Australia, New Zealand and much of Europe. If you are new to it, read what Peppol is and how it works. IRAS now uses InvoiceNow for GST: businesses in scope must send invoice data to IRAS through an InvoiceNow-ready solution.

Date	Who is in scope
May 2025	Voluntary adoption opened for GST-registered businesses
November 1, 2025	Newly incorporated companies that register for GST voluntarily within six months of incorporation
April 1, 2026	All new voluntary GST registrants
From 2028 onward (announced)	New compulsory registrants and existing GST-registered businesses, in phases by annual supply size

The later phases were announced in 2026, with IRAS saying it would notify existing registrants of their own implementation dates. Reported dates run from April 1, 2028 for smaller businesses to 2031 for the largest, but check the current IRAS timetable for your date rather than relying on summaries. Our overview of e-invoicing mandates for 2027 tracks how Singapore compares with other countries.

Our generator creates PDF invoices in your browser. It is not an InvoiceNow access point and does not transmit data to IRAS. If you are in scope, you will need an InvoiceNow-ready accounting system; the PDF can still serve as a readable copy for your customer.

Checklist: Singapore GST tax invoice

1. Title the document "Tax Invoice" (only if you are GST registered).
2. Your name, address and GST registration number.
3. A unique invoice number and the invoice date, issued within 30 days of supply.
4. The customer's name and address (full tax invoice).
5. A description of each item, with quantity and unit price.
6. Any discount, shown before GST.
7. Total excluding GST, the GST rate, the GST amount and the total including GST.
8. Separate lines for zero-rated or exempt items.
9. Singapore dollar figures for GST if the invoice is in another currency.
10. Payment terms and instructions.
11. Your InvoiceNow status checked, if you registered for GST recently.

The corporate invoice template has room for a registration number in the header and a tax summary block, which suits full tax invoices.

Common mistakes on Singapore tax invoices

• Charging GST before registration takes effect. Only registered businesses may charge GST.
• Using a simplified invoice above S$1,000. The limit includes GST.
• Leaving out the GST registration number. Customers cannot claim input tax without it.
• Showing GST only in a foreign currency. Show the GST amount in Singapore dollars too.
• Applying 9% to an export. Qualifying exports and international services are zero-rated.
• Assuming a PDF meets InvoiceNow. If you are in scope, data must go through an InvoiceNow-ready solution.
• Skipping invoice sequence checks. Gaps and duplicates raise questions; our invoice number generator helps keep numbers consistent.

Official sources

IRAS's invoicing customers page lists the full and simplified tax invoice details, and its GST InvoiceNow requirement page sets out who is in scope and when. Check both before you change your invoicing process.