A Comprehensive Guide On Handling Singapore Tax Invoice

As a business owner, understanding the Singapore tax invoice requirements are crucial regardless of your business type and operations scale. These documents are an essential part of an organization’s bookkeeping procedures.

Also, they’ll help your business file taxes and (for GST-registered businesses) support GST input tax claims and related GST reporting. In Singapore, GST input tax claims must generally be supported by valid tax invoices/customer accounting tax invoices (or simplified tax invoices where applicable), in line with IRAS invoicing and record-keeping guidance. 

Are you a business owner in Singapore interested in learning more about Singapore tax invoices? You’re at the right place. This article will reveal all the essential Singapore tax invoice details you need to know.

What is an Invoice?

An invoice is a commercial document businesses issue to customers to request payment for goods and services, and to document the details of the supply (e.g., what was supplied, when, and at what price). Depending on the transaction and whether GST applies, certain invoices may also serve as supporting documents for GST reporting and input tax claims. 

There are different invoice formats, but in most cases, the document will contain information about the cost of the product or service sold, the product or service code, the name of the customer, the billing address of the customer, the name and address of your business, invoice number, and so on. 

An invoice will improve your interactions with customers. They’ll be correctly informed of their payment obligations. Also, invoices are great tools for settling disputes with customers.

Let’s say you have a customer who wants a particular product replaced. The invoice presented by the customer will serve as evidence to prove that he/she previously got the product from you. 

Difference Between Singapore Tax Invoice and Normal Invoice

There are notable differences between a Singapore tax invoice and a retail invoice. They include the following:

Goods and Services Tax (GST) Number 

The Goods and Services Tax is an indirect tax that the Inland Revenue Authority of Singapore (IRAS) levies on goods and services. This tax is also levied on the importation of goods.

GST is charged on taxable supplies made in Singapore. The current GST rate in Singapore is 9% (as at 1 January 2024). A GST registration number on a tax invoice is required for GST-registered businesses, and IRAS requires the supplier’s GST registration number to be reflected on tax invoices, simplified tax invoices, and receipts. 

A Singapore tax invoice is issued to customers with the Goods and Services Tax number, while a retail invoice will not have one.

The content of a tax invoice is most likely to contain the same details as a retail invoice, including the name of the buyer and seller, the billing address of the buyer and seller, the receipt number, and so on. 

Invoice Copies

A retail invoice is a duplicate document. As a result, only two copies will be made – one for the buyer and the other for the issuer. 

Purpose Of the Invoice

The main purpose of a Singapore tax invoice (for standard-rated supplies made to a GST-registered customer) is to support the customer’s GST input tax claim (subject to meeting input tax claiming conditions) and to document the GST charged. A retail invoice/receipt is commonly used to document sales to end-consumers and for financial accounting and record-keeping. 

GST Registration

Businesses can only issue Singapore tax invoices when they are GST registered. As a GST-registered company, you’ll serve as an indirect collecting agent for the IRAS. 

What are the Contents of a Singapore Tax Invoice?

As a business owner, if you’re interested in designing a Singapore tax invoice for your company, it should contain the following information: 

• Invoice number
• Name of the buyer
• Name of the seller
• Invoice issuance date
• Billing address of the seller
• Billing address of the buyer
• Quantity of items purchased
• Description of items purchased
• Amount of tax charged
• Price of each item
• Tax identification number
• GST charges
• Total cost
• Signature of any relevant parties

IRAS sets out specific information that must appear on a tax invoice. To align with IRAS invoicing guidance, ensure your tax invoice contains (at minimum): 

• The words “Tax Invoice” 

• Supplier’s name and address 

• Supplier’s GST registration number 

• Invoice date 

• A unique invoice identifying number (e.g., invoice number) 

• Customer’s name and address 

• Description of goods and services 

• GST rate (e.g., 9%) 

• Total amount payable excluding GST 

• Total GST 

• Total amount payable including GST 

• If you make different types of supplies (e.g., standard-rated, zero-rated, exempt), the invoice should also show the relevant breakdowns so that the gross amount payable for each type of supply is separately stated, where applicable (per IRAS guidance). 

A “signature” is not listed by IRAS as a mandatory field for a GST tax invoice. You may include additional fields for your business needs, but ensure the IRAS-required fields are present and correct. 

When Should You Issue a Tax Invoice?

If you’re a GST-registered company dealing with a customer that has a valid GST registration, you must issue them a Singapore tax invoice. According to IRAS regulations, you’re expected to issue a GST tax invoice within 30 days of completing the transaction. 

Your customers will use the GST invoice to prove their tax input compliance to government authorities. 

IRAS guidance states that, in general, a tax invoice must be issued within 30 days from the time of supply for standard-rated supplies made to a GST-registered customer. 

If your customer is not GST-registered, IRAS guidance indicates a tax invoice generally does not need to be issued (and businesses often issue a receipt instead). Tax invoices are primarily required for sales made to another GST-registered business to support that customer’s input tax claim. 

InvoiceNow (e-invoicing) and practical compliance points (IRAS-led updates)

IRAS has introduced a major compliance development linked to Singapore’s nationwide e-invoicing initiative, InvoiceNow (based on the PEPPOL e-invoicing framework). GST-registered businesses will be required to transmit invoice data to IRAS using InvoiceNow-Ready Solutions via the InvoiceNow network, with mandatory participation being phased in. 

Key points to be aware of: 

• Phased mandatory adoption (voluntary GST registration): IRAS has announced that mandatory InvoiceNow participation will apply first to certain newly incorporated companies that voluntarily register for GST within a defined period from incorporation, followed by a broader group of new voluntary GST registrants (with the phases commencing from 1 November 2025 and from 1 April 2026, respectively, per IRAS’ published timeline). 

• What this means operationally: even if your invoices already contain the right wording and particulars, businesses affected by the requirement may need to ensure they are using an InvoiceNow-Ready Solution and are capable of transmitting invoice data to IRAS as part of the GST registration conditions and ongoing compliance expectations. 

• Record retention remains essential: IRAS requires businesses to retain tax invoices issued/received (and other supporting records) for at least 5 years. This applies regardless of whether invoices are issued on paper, as PDFs, or via e-invoicing systems. 

• Simplified tax invoice threshold: Where the total amount payable for a supply (including GST) does not exceed S$1,000, IRAS allows a simplified tax invoice with fewer particulars. This can be useful for high-volume, lower-value B2B transactions, but you must still include the required minimum details (e.g., supplier details and GST number, date, invoice number, description, total payable including GST, and a statement that the price includes GST). 

• Common pitfalls IRAS focuses on (practical): 

• Missing “Tax Invoice” wording for B2B standard-rated supplies to GST-registered customers. 

• Not showing totals clearly (excluding GST, GST amount, including GST), or mixing standard-rated and exempt/zero-rated items without separate disclosure where needed. 

• Using the wrong GST rate during rate changes or transitional periods (ensure your systems apply 9% where applicable for supplies on/after 1 January 2024, and apply time-of-supply rules correctly). 

• Poor controls over credit notes/debit notes and adjustments (which can impact GST reporting and your customer’s input tax position). 
  If you are unsure whether your invoicing process meets IRAS’ requirements—especially if you are (or will be) a new voluntary GST registrant—it is worth reviewing your billing workflow, accounting software capabilities, and InvoiceNow readiness together, rather than treating “tax invoice” as just a template. 

How Can We Help?

It can be tough to account for tax and create Singapore tax invoices while focusing on other business operations. As a result, many businesses find it difficult to keep up with IRAS regulations.

Don’t wait till the IRAS sanctions you before paying attention to your tax invoicing. You can hire us to do all the heavy lifting for you. Premia TNC is an accounting and business consultancy firm that has a team of top business professionals.

We are passionate about ensuring that all our services will support your company’s long-term growth, providing our clients with high-quality, affordable professional advice on all corporate issues, including the Singapore tax invoice process.

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