A GST-registered business must issue a tax invoice to its GST-registered customers within 30 days of the time of supply, and it must carry specific particulars: the words “tax invoice”, an invoice number, date, your name, address and GST registration number, the customer’s name and address, a description, amounts before GST, the GST rate and GST amount, and the total. For purchases of $1,000 or less including GST, a simplified tax invoice with fewer details is allowed. When you buy, the same documents decide whether your input tax claim survives an IRAS review.
Raffles Corporate Services works with a panel of experienced Singapore law firms who offer cost-effective and efficient legal service and advice. This article is general information only and is not legal advice.
What must a full tax invoice show?
IRAS’s GST General Guide for Businesses lists the information required on a tax invoice. Check each of these on every invoice you issue, and on every supplier invoice before you claim GST from it.
- The words “tax invoice” in a prominent place
- An identifying number, such as an invoice number
- The date of issue
- The supplier’s name, address and GST registration number
- The customer’s name and address
- A description sufficient to identify the goods or services and the type of supply
- For each description, the quantity or extent of services, and the amount payable excluding GST
- Any cash discount offered
- The total amount payable excluding GST, the GST rate and the total GST chargeable, shown as a separate amount
- The total amount payable including GST
- If the invoice includes exempt, zero-rated or other supplies, a breakdown showing the gross total for each type separately
The current GST rate is 9%, in effect since 1 January 2024. The tax invoice should show GST as its own amount, not buried in the price.
When can you use a simplified tax invoice instead?
If the total including GST does not exceed $1,000, you may issue a simplified tax invoice. It leaves out the customer’s name, for example, which suits counter sales. Under the IRAS guide, it should show:
- your name, address and GST registration number
- an identifying number
- the date of issue
- a description of the goods or services
- the total amount payable including GST
- the words “Price Payable includes GST”
IRAS also notes that a receipt or debit note can double as a simplified tax invoice if it contains all of that information. Above $1,000, you cannot leave out required particulars. IRAS gives the example that writing “Cash” in place of the customer’s name and address is not acceptable on a tax invoice above $1,000, because the customer needs a valid tax invoice to support the input tax claim.
| Point | Full tax invoice | Simplified tax invoice |
|---|---|---|
| Total including GST | Any amount | $1,000 or less |
| Customer’s name and address | Required | Not required |
| GST rate and GST amount shown separately | Required | Not required; wording “Price Payable includes GST” |
| Breakdown of mixed supplies | Required where relevant | Not listed |
| Supports input tax claim for the customer | Yes, if addressed to the customer | Yes, for purchases of $1,000 or below |
Who should and should not issue a tax invoice?
IRAS says a tax invoice must not be issued if you are not GST-registered, if you sell goods under the Gross Margin Scheme, or if you are the supplier in a self-billing arrangement where the customer issues the invoice. You need not issue a tax invoice for zero-rated supplies, exempt supplies, deemed supplies, or sales to customers who are not GST-registered, although you may choose to. If you issue one for a zero-rated supply, include all the particulars and show that GST is charged at 0%.
A non-registered customer can be given a receipt instead. If you do issue receipts, IRAS says they must be serially printed and show your name and GST registration number, the date, the total amount payable including GST and the words “Price payable includes GST”.
Issue one original per sale. If a customer loses it, a duplicate should be marked “Copy” or “Duplicate”.
Documents that are not bills for payment, such as a sales order, pro-forma invoice or statement of account, are generally not treated as invoices for time-of-supply purposes. They also do not replace a proper tax invoice for the customer’s claim.
What if the invoice is in a foreign currency?
For a local sale denominated in a foreign currency, IRAS requires three amounts on the tax invoice to be shown in Singapore dollars, converted at an approved exchange rate: the total excluding GST, the total GST payable and the total including GST. Examples of acceptable sources include rates published by local banks or a locally circulated newspaper. The rate must be updated at least once every three months and used consistently for internal reporting, accounting and GST. If your accounts use a different rate from the invoice, see our article on foreign-currency invoices and the GST claim.
What do you need for a credit note?
When you reduce an earlier charge, a credit note is the document that supports the adjustment. IRAS guidance on adjustments sets out what the document should show: the heading “Credit Note”, an identifying number, your name, address and GST registration number, a description of what is credited, the reason, and the quantity and value. In practice it should also point to the original invoice so both sides can match it. You reduce your output tax in the return for the accounting period in which the credit note is issued. The customer’s side then needs to reduce its input tax claim. Our guide on adjusting a GST claim from a credit note shows how that works for a conditional discount.
The IRAS page we relied on deals specifically with rate-change adjustments, so check IRAS’s current GST pages for your exact scenario before relying on a particular layout.
What makes an input tax claim fail on audit?
IRAS’s conditions for input tax include that the supply was made to you, the purchase is supported by a tax invoice addressed to you (or a simplified tax invoice for $1,000 or below), and the goods or services are for your business purpose. Claims also fail for documentary reasons that look small on the day. The most common are listed below.
| Problem found | Why it matters | Fix |
|---|---|---|
| Invoice addressed to a director, another group company or an old company name | The claim must be supported by a tax invoice addressed to you | Ask the supplier for a corrected invoice or credit and reissue |
| No supplier GST registration number, or supplier not registered | A non-registered business must not issue a tax invoice | Verify the number before paying; do not claim if invalid |
| Document is a quotation, pro-forma, statement or delivery order | Not a tax invoice | Obtain the actual tax invoice |
| Total above $1,000 but customer details missing | Required particulars cannot be omitted above $1,000 | Supplier reissues complete invoice |
| Foreign-currency invoice with no SGD amounts | Amounts must be converted at an approved rate | Request an invoice or tax invoice showing the SGD conversions |
| Original not held when claiming | IRAS expects the original at the time of claiming when you claim by posting date | Retain originals; keep scans under your record-keeping system |
| Input tax claimed twice | Needs controls against double claiming | Match invoice numbers in the ledger |
IRAS also expects reasonable steps to ensure that purchases were not part of a missing trader fraud arrangement, and records of those steps are part of what should be kept. GST records generally must be kept for at least five years.
For what you can and cannot claim after documentation is sorted, read our guide to input tax claims. If a director’s other business invoices you, see checking the supplier before claiming GST.
Example: an invoice that looks right but fails
Example (hypothetical): A consulting company buys software services for $3,270 including GST. The supplier’s invoice has a number, a date, a description and a total, but addressed only to the director by first name, with no GST amount shown separately and no supplier GST number. The bookkeeper posts it and claims $270 as input tax. On review, none of the following can be defended: the invoice is above $1,000 so it cannot be a simplified invoice, it is not addressed to the company, and a GST amount and supplier registration number are missing.
The fix is to ask the supplier for a proper tax invoice in the company’s name. If the supplier cannot provide one, the company should adjust the claim in the return rather than leave it.
Invoice review checklist
- “Tax invoice” wording, number and date present
- Supplier name, address and GST registration number present, and the registration verified
- Customer name and address are the correct legal entity
- GST rate and GST amount shown separately (full invoices)
- Total at or below $1,000 for any simplified invoice
- Foreign-currency invoices show SGD totals using a consistent approved rate
- Credit notes linked to original invoices and recorded in the right period
- Originals or scans retained for at least five years
Frequently asked questions
How long do I have to issue a tax invoice?
IRAS’s guide says within 30 days from the time of supply, for standard-rated supplies to GST-registered customers.
Can a receipt support my input tax claim?
Only if it contains everything required for a simplified tax invoice and the purchase is $1,000 or below including GST. IRAS says a receipt or debit note can double as a simplified tax invoice in that case.
Can I claim input tax on client entertainment meals with a simplified invoice?
IRAS allows a simplified tax invoice for entertainment expenses on food and drinks regardless of value, but you must also keep alternative evidence of payment and details of the entertainment. Other entertainment items need a full tax invoice.
Do I show GST on an invoice for a zero-rated export?
A tax invoice is not required for zero-rated supplies. If you choose to issue one, show all the particulars and that GST is charged at 0%.
Do I need an invoice if I have InvoiceNow?
InvoiceNow is a transmission network and does not remove the need for compliant invoice content. See our overview of GST InvoiceNow.
How do I check my supplier’s GST number?
Use IRAS’s online GST-registered business search before you pay a large invoice and keep a screenshot with the file.
Need help with GST invoicing and claims?
Raffles Corporate Services can review your invoice templates, check purchase documents before GST returns are filed, and help with bookkeeping and GST filing. Contact us at [email protected] or on WhatsApp at +65 8501 7133. For a first-time GST registration, see our GST registration guide.
Kevin Yeo, Raffles Corporate Services