How to Write a Tax Invoice in Singapore

A complete guide to GST-compliant invoicing

A Singapore tax invoice needs 12 IRAS-prescribed fields: your business name, address and GST registration number, the customer's name and address, the invoice date and number, a description and quantity of the goods or services, the total excluding GST, the GST rate and amount, and the total including GST. Standard-rated supplies are taxed at 9%; registration is compulsory above S$1 million turnover, and supplies of S$1,000 or less can use a simplified invoice.

Invoicing in Singapore requires compliance with local GST regulations and specific formatting standards. Whether you are a freelancer, small business owner, or agency, this guide covers everything you need to create professional, legally compliant invoices in Singapore using SGD (S$).

Legal Requirements for Singapore Invoices

✓Register for GST if your taxable turnover exceeds S$1 million in the past 12 months or is expected to exceed S$1 million in the next 12 months. Display your GST registration number on all tax invoices.
✓Issue tax invoices for all standard-rated supplies to GST-registered customers. A tax invoice must contain at least 12 prescribed fields as specified by IRAS, including the total amount payable including GST.
✓Issue simplified tax invoices for supplies totalling S$1,000 or less (GST-inclusive). Simplified invoices require fewer details but must still show the GST-inclusive price and your GST registration number.
✓Apply customer accounting for prescribed goods (such as mobile phones, memory cards, and off-the-shelf software) where the total supply exceeds S$10,000, shifting the GST accounting obligation to the buyer.
✓Comply with all IRAS (Inland Revenue Authority of Singapore) requirements for invoicing, record-keeping, and GST return filing. IRAS conducts regular audits and non-compliance can result in fines and penalties.
✓Issue credit notes when reducing the amount of GST previously charged, clearly referencing the original tax invoice number, the reason for the credit, and the adjusted GST amount.
✓Issue debit notes when additional charges are added after the original invoice, ensuring the debit note references the original invoice and includes the additional GST amount.

Step-by-Step: Create an Invoice for Singapore

Follow these steps to create a compliant Singapore invoice with proper GST handling.

Estimated time: About 10 minutes

1
Enter Your GST Registration Number
Input your GST registration number (format: M followed by 8 digits and a letter, e.g., M12345678A), business name, and registered address. If you are not GST-registered, you must not charge or display GST on your invoices.
2
Set Up Sequential Invoice Numbering
Configure a sequential invoice numbering system. IRAS requires invoices to be numbered consecutively and uniquely. Each invoice number must identify the document clearly, and gaps in numbering may raise questions during audits.
3
Add Client Details
Enter your client's name, address, and GST registration number if applicable. For B2B transactions with GST-registered customers, the buyer's GST registration number helps with proper input tax claims.
4
Create Line Items with GST
Add each product or service as a line item with quantity, unit price, and description. Indicate whether each item is standard-rated (9%), zero-rated (0% for exports and international services), or exempt from GST.
5
Calculate the 9% GST
Apply the 9% GST rate to all standard-rated supplies. Show the amount excluding GST, the GST amount, and the total amount including GST. For multiple items at different rates, break down the GST calculation for each rate category.
6
Set Payment Terms in SGD
Specify payment terms such as 30 days from invoice date. Include your bank details for PayNow, GIRO, or direct bank transfer, which are the most common business payment methods in Singapore.
7
Generate and Download the PDF
Create a PDF invoice that includes all 12 IRAS-prescribed fields: your name, address, and GST number; the customer's name and address; invoice date and number; description and quantity of goods or services; total excluding GST; GST rate; GST amount; and total including GST.
8
File GST Returns with IRAS
Record the invoice for inclusion in your quarterly GST return (GST F5). Returns are due within one month after the end of each prescribed accounting period. E-file through myTax Portal to meet IRAS deadlines and avoid late filing penalties.

Tips for Invoicing in Singapore

Consider voluntary GST registration even if your turnover is below S$1 million. It can enhance your business credibility, allow you to claim input tax on business purchases, and may be advantageous if most of your customers are GST-registered businesses.
Be aware of the Tourist Refund Scheme (TRS) if you sell to tourists. Tourists can claim a GST refund on goods purchased in Singapore and brought out of the country, provided the purchase is at least S$100 from a participating retailer.
Adopt e-invoicing through the Peppol network, which Singapore's IMDA actively promotes via the InvoiceNow initiative. E-invoicing reduces processing time, lowers costs, and provides a structured data format for seamless integration with accounting systems.
Keep all business and tax records for at least 5 years from the relevant Year of Assessment. IRAS can request records for verification at any time, and inadequate record-keeping can lead to estimated assessments and penalties.
File your GST returns quarterly via IRAS myTax Portal by the due date (one month after the end of the accounting period). Late filing attracts a penalty of $200 immediately, with an additional $200 for every month the return remains outstanding, up to a maximum of $10,000.

Singapore Invoicing FAQ

When must I register for GST in Singapore?

You must register for GST if your taxable turnover exceeded S$1 million in the past 12 months (retrospective basis) or is expected to exceed S$1 million in the next 12 months (prospective basis). Registration must be made within 30 days of becoming liable. You can also voluntarily register if your turnover is below the threshold, but voluntary registration commits you to remaining registered for at least two years.

What is a simplified tax invoice and when can I use it?

A simplified tax invoice can be issued for supplies totalling S$1,000 or less (GST-inclusive). It requires fewer details than a full tax invoice: your business name, GST registration number, invoice date, description of goods or services, and the GST-inclusive total with a statement that the price includes GST. Your customer can use a simplified tax invoice to claim input tax if the GST-inclusive amount does not exceed S$1,000.

What is customer accounting and does it apply to me?

Customer accounting is a GST mechanism where the responsibility for accounting for GST shifts from the supplier to the customer. It applies to prescribed goods such as mobile phones, memory cards, and off-the-shelf software when the total value of the supply exceeds S$10,000 and both parties are GST-registered. If you sell these goods, you issue an invoice without GST and the buyer accounts for it as both output and input tax.

What are the penalties for late GST filing?

IRAS imposes a penalty of $200 immediately when a GST return is not filed by the due date. An additional $200 is charged for every complete month the return remains outstanding, up to a maximum penalty of $10,000. In addition, IRAS may issue an estimated assessment of the GST payable and charge a 5% late payment penalty on the estimated tax. Repeated non-compliance may lead to prosecution.

Can I claim input tax on all business purchases?

You can claim input tax on most business purchases made for taxable supplies, provided you have a valid tax invoice. However, certain expenses are specifically excluded from input tax claims, including club subscription fees, medical and accident insurance premiums for employees (unless compulsory), family benefits, and costs related to motor cars. Only GST-registered businesses can claim input tax, and claims must be made within 5 years.