Record Keeping Guide for GST-registered Businesses (PDF, 381KB)
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A tax invoice or customer accounting tax invoice is the main document for supporting an input tax claim.
You must keep the tax invoices issued to your customers, and those given to you by your suppliers, for at least 5 years. You do not need to submit them with your GST returns.
As part of IRAS’s digitalisation drive and Singapore’s nationwide e-invoicing initiative, GST-registered businesses must transmit invoice data to IRAS using InvoiceNow-Ready Solutions. Mandatory participation will be implemented in phases. For more details, refer to GST InvoiceNow Requirement.
Common billing documents
| Document type | When to issue and to who |
|---|---|
| Tax invoice | Providing standard-rated supplies to GST-registered customers |
| Simplified tax invoice | Providing standard-rated supplies ≤ $1,000 (including GST) to GST-registered customers |
| Receipt | Providing any supply to non-GST registered customers |
| Credit note | Providing corrections to original invoice. |
When to issue a tax invoice and what must be shown
A tax invoice must be issued:
- To your GST-registered customer. Your customer needs to keep this tax invoice as a supporting document to claim input tax on its standard-rated purchases.
- Within 30 days from the time of supply.
A tax invoice does not need to be issued:
- To a non-GST registered customer;
- For zero-rated supplies, exempt supplies and deemed supplies; or
- For deposits collected under the Beverage Container Return Scheme (BCRS) as these deposits are not subject to GST. However, you are encouraged to include BCRS deposits in your tax invoices and receipts issued for the sale of the beverages to ensure price transparency for your customers. Please refer to GST and BCRS Deposit for more information about the GST treatment and requirements, including invoicing guidelines.
Important: Even if a tax invoice is not required, you must still maintain proper business records to support the GST treatment applied.
What must be shown on a tax invoice
All required information must be clearly stated on a single document. Missing or incomplete information may result in your customer being unable to claim input tax.
Your GST registration number must be clearly shown on the tax invoices. Below are some commonly used formats for displaying the GST registration number:
| Scenario | Commonly used formats |
|---|---|
| Your Unique Entity Number (UEN) and GST registration number are the same |
|
| Your UEN and GST registration number are different E.g. UEN = 123456789A; GST registration number = M21234567K |
|
A tax invoice requires the following information:
| Required Information | Example(s) |
|---|---|
| Must state "Tax Invoice" in a prominent place | Tax Invoice |
| Supplier’s name | ABC Pte Ltd |
| Supplier’s address | 123 Main St |
| Supplier’s GST registration number | GST: 123456789A |
| Date of issue of the invoice | 15 Jan 2026 |
| Invoice identifying number | INV-001 |
| Customer’s name | XYZ Company |
| Customer’s Address | 456 Business Ave |
| Description of goods/services supplied | Office supplies |
| GST Rate | 9% |
| Total amount payable excluding GST* | $100.00 |
| GST amount* | $9.00 |
| Total amount payable including GST* | $109.00 |
If you issue a tax invoice for zero-rated supplies, state on the invoice that GST is charged at 0%. Where applicable, separately state the details and gross amount payable for each type of exempt, zero-rated, or other supply. Please refer to a sample tax invoice.
*If you invoice your customer in a foreign currency, these items must be converted into Singapore dollars using the approved exchange rates for GST purpose (PDF, 185KB). For more information, refer to foreign currency transactions.
Calculate GST on a tax invoice
There are 2 ways to compute the total GST amount on your tax invoice when your customer purchases several items of standard-rated supplies:
- Item-by-item method: Apply 9% to the value of each item (excluding GST), and then sum the GST computed for each item
- Subtotal method: Apply 9% to the sum of the value of each item (excluding GST)
The total GST computed may differ due to rounding because of the method you have chosen. Both methods are acceptable and you must apply the chosen method consistently.
Example:
You are a stationary retailer. You sell 3 pens to your customer. Each pen is priced at $1.28 (excluding GST). You may apply either of the following methods for calculating GST on a tax invoice:
| Method | Example |
|---|---|
| Item-by-item (Apply 9% to each item, then sum up) |
Amount payable excluding GST: 3 pens x $1.28 = $3.84 Working: GST (for 1 pen): $1.28 x 9% = $0.12 GST: $0.12 + $0.12 + $0.12 = $0.36 Total payable: $4.20 |
| Subtotal method (Apply 9% to subtotal) |
Amount payable excluding GST: 3 pens x $1.28 = $3.84 GST: $3.84 x 9% = $0.35 Total payable: $4.19 |
Rounding off total GST
You can round the total GST to be paid on all goods and services to the nearest cent (i.e. two decimal places).
You may also choose to round your total bill (i.e. total amount payable including GST) to the nearest 5 cents to facilitate cash payment by your customers.
Whether a bill should be rounded up or rounded down to the nearest 5 cents is your business decision. However, the decision for the amount to be rounded up or down must be applied consistently.When to issue a simplified tax invoice and what must be shown
You may issue a simplified tax invoice instead of a regular tax invoice if the total amount payable for your supply (including GST) does not exceed $1,000.
A simplified tax invoice only requires the following information:
| Details | Example(s) |
|---|---|
| Supplier’s name | ABC Pte Ltd |
| Supplier’s address | 123 Main St |
| Supplier’s GST registration number | GST: 123456789A |
| Date of issue of the invoice | 15 Jan 2026 |
| Invoice identifying number | INV-001 |
| Description of goods/services supplied | Office supplies |
| Total amount payable including GST chargeable | $109.00 |
| A statement like "price payable includes GST" | Price payable includes GST |
A sales voucher or debit note can double up as a simplified tax invoice if it contains all the required information above.
If you are including deposits collected under the Beverage Container Return Scheme (BCRS) in your simplified tax invoices, please refer to GST and BCRS Deposit for more information about the GST treatment and requirements, including invoicing guidelines.
When to issue a receipt and what must be shown
If your customer is not GST-registered, you may issue a receipt instead of a tax invoice. Receipts may be used as proof of sales made to customers and you must retain a duplicate copy of each receipt issued.
If you choose not to issue receipts, IRAS’ approval is not required. However, you must ensure that:
- Your customers agree to this arrangement
- Tax invoices are still issued to GST-registered customers; and
- Proper records of all business transactions are maintained for tax purposes. You may use a cash register or accounting software to maintain these records.
A receipt must be serially printed and have all the following details:
| Details | Example(s) |
|---|---|
| Date of issue of the receipt | 15 Jan 2026 |
| Supplier’s name | ABC Pte Ltd |
| Supplier’s GST registration number | GST: 123456789A |
| Total amount payable including GST chargeable | $109.00 |
| A statement to inform customer that the price payable includes GST. | “Price payable includes GST” |
If you are including deposits collected under the Beverage Container Return Scheme (BCRS) in your receipts, please refer to GST and BCRS Deposit for more information about the GST treatment and requirements, including invoicing guidelines.
When to issue a credit note and what must be shown
A credit note is issued to correct a mistake or to give a credit to your customer under the following situations:
- To correct a mistake (e.g. goods invoiced as standard-rated, which should have been exempt or zero-rated);
- Goods or services were not supplied
- Charges are partly or fully waived before/after delivery of the goods
- Goods or services are accepted, but terms of the contract are not fully met (e.g. sub-standard goods are accepted by the customer at a reduced price)
- Goods are returned or services are not accepted; or
- Discount given for a past transaction.
A credit note must show the number and date of the original tax invoice. If you are unable to do so (e.g. because returned goods cannot be identified with a particular tax invoice), you must maintain other documentary evidence that you have accounted for GST on the original supply.
A credit note must include the following information:
| Details | Example(s) |
|---|---|
| Credit note identifying number | CN-0001 |
| Date of issue of the credit note | 15 Jan 2026 |
| Supplier’s name | ABC Pte Ltd |
| Supplier’s address | 123 Main St |
| Supplier’s GST registration number | GST: 123456789A |
| Customer’s name | XYZ Company |
| Customer’s Address | 456 Business Ave |
| Corresponding tax invoice identifying number | INV-001 |
| Date of issue of the tax invoice | 14 Jan 2026 |
| Detailed description to identify the goods and services that credit is allowed for. Including quantity of each description (if any) | Office supplies |
| Amount credited for each description | $100.00 |
| GST Rate | 9% |
| GST amount credited | $9.00 |
| Total amount credited, including tax | $109.00 |
|
Document must have the title, "Credit Note" in a prominent place (only for credit notes issued in relation to rate change) |
Credit Note |
Credit notes for foreign denominated tax invoices
You should use the historical exchange rate in accordance to the tax invoice. However, if your customer is GST-registered, you can choose to use the prevailing exchange rate instead. Whether you choose the historical or prevailing exchange rate, you are required to apply the chosen rate consistently.
Accounting for credit notes in GST returns
When you issue a credit note, you generally account for the adjustment in the accounting period when you issued the credit note.
However, in some cases, you must file a GST F7 return to adjust the original accounting period in which the time of supply was triggered. Refer to the table below for an overview of common situations and what to file.
For credit notes issued relating to customer accounting supplies, you may refer to our e-Tax Guide on GST: Customer Accounting for Prescribed Goods (PDF, 575KB) for guidance on how the adjustments should be made.
| Common situations | How to account for the credit note |
|---|---|
| Credit note issued for reason other than wrong GST treatment. | GST F5 Return – Account for the credit note in the accounting period in which it was issued. |
| Credit note issued to correct wrong GST treatment, where both conditions for correcting errors in the next GST F5 return are met. | GST F5 Return – Account for the adjustment in the accounting period in which the credit note was issued. |
| Credit note issued to correct wrong GST treatment, where at least one of the conditions for correcting errors in the next GST F5 return is not met. | GST F7 Return – Correct the original accounting period in which the time of supply was triggered. |
Follow the steps below to determine which return to file
Step 1: Check why you issued the credit note
Check if you had issued the credit to correct a wrong GST treatment. Examples of incorrect GST treatment include charging GST to your supply when GST should not be applied or applying the wrong GST rate to a supply.
- If no — account for the adjustment in your current GST F5 return. No further action is needed.
- If yes — proceed to Step 2.
Step 2: Check if you meet the conditions to correct errors in your next GST F5 return
You may correct the error in your next GST F5 return if both of the following conditions are met:
- Condition 1: The net GST amount in error for all the affected prescribed accounting periods is not more than $3,000. Net GST amount in error refers to the difference between the additional output tax to be paid in Box 6 and the additional input tax to be claimed in Box 7
- Condition 2: The total amount in error for all other boxes except Box 6, 7 and 12 (pre-registration input tax claims) for each of the affected accounting period(s) is not more than 5% of the total value of supplies (Box 4) declared in the submitted GST return. In the case where there was no supply made in the affected accounting period, the 5% rule applies to the total value of the taxable purchases (Box 5).
If you meet both conditions 1 and 2, account for the adjustment in your current GST F5 return.
If you do not meet one or both conditions, proceed to Step 3.
Step 3: File a GST F7 return
Log into myTax Portal to correct the errors made in the past accounting period via a GST F7 return. For guidance on filing GST F7, refer to Correcting errors made in GST return (filing GST F7)
Note: Filing a GST F7 return is mandatory in this situation. You cannot account for the adjustment in your current GST F5 return.
If you issue a credit note on 30 Jun 2026 to cancel a tax invoice issued for a sale made on 1 Jan 2026, and GST was correctly accounted for on the original transaction, you should not file a GST F7 for credit note adjustments.
Instead, you should reduce the value of standard-rated supplies (Box 1) and output tax due (Box 6) accordingly in the GST F5 return for the accounting period covering Jun 2026.
Choosing not to adjust the GST amount when issuing a credit note
In your credit note, you can choose not to adjust the GST amount charged on the original tax invoice if all the following conditions are satisfied:
- Both supplier and customer agree in writing not to adjust the original GST amount. This written agreement does not need to be a formal contract. It could be the correspondence between supplier and customer via letters or emails. Both parties must retain the written agreement as part of their GST records. The written agreement does not need to be submitted to IRAS, unless requested.
- Customer is a fully taxable person (i.e. does not make any exempt supplies).
- The credit note, which is issued without any adjustment to the original GST amount, should contain the statement "This is not a credit note for GST purposes". If such credit notes are issued by the supplier, both the supplier and customer do not need to adjust the value of their taxable supplies/ purchases or the related output/ input tax.
If any condition is not satisfied, you must adjust the GST amount and declare the adjustment accordingly.
Other billing documents
| Document type | When to issue and to who |
|---|---|
| Debit note | You should only issue a debit note to request for payment for transactions where no GST is charged (e.g. internal billings within the same company), or to suppliers from whom credit is due. For all other standard-rated supplies to GST-registered customers, you must issue a tax invoice or simplified tax invoice (where the total amount payable including GST does not exceed $1,000). This enables your customer to support his input tax claims. Issuing debit note to record credit received from suppliers If credit notes are subsequently received from the suppliers, they should be compared with the debit notes issued to ensure that the figures match. |
| Customer accounting tax invoice | Providing relevant supplies subject to customer accounting to GST-registered customers Your GST-registered customer is required to retain this customer accounting tax invoice as a supporting document to account for the output tax on this supply on your behalf, as well as to claim the input tax on the purchase. For details on the information that must be shown on a customer accounting tax invoice, please refer to the e-Tax Guide, GST: Customer Accounting for Prescribed Goods (PDF, 575KB). |
| Investment Precious Metals (IPM) invoice | Providing exempt supply of investment precious metal (IPM) to any customer. The GST: Guide on Exemption of Investment Precious Metals (IPM) (PDF, 397KB) lists the information you must include on an invoice issued for an exempt supply of IPM. |
Special arrangement: Self-billing
Self-billing is a billing arrangement between a GST-registered supplier and a GST-registered customer, where the customer, instead of the supplier, prepares the supplier's tax invoice/ customer accounting tax invoice and sends a copy to the supplier.
In some industries (e.g. publication industry), the business arrangement is such that customers, instead of the supplier, will determine and verify the final value of the goods delivered or the services rendered to them. Hence, it is more convenient for the customer, rather than the supplier, to issue the tax invoice/customer accounting tax invoice.
Customers that prescribe purchase documentation for their suppliers may also prefer self-billing to facilitate their internal controls and accounting system.
Matters to consider before adopting self-billing
Before you adopt self-billing, you should take note of the following:
- You will have additional responsibilities to ensure that all conditions for self-billings are satisfied.
- You must ensure that the GST amount is correctly calculated for the goods and services supplied to you.
- You must ensure that any errors in buyer-created tax invoices or customer accounting tax invoices are corrected promptly, and that the supplier is duly informed.
How to adopt self-billing
To adopt self-billing, the customer must first verify that all conditions in the Self-Review of eligibility and declaration on use of self-billing form are satisfied, and submit the completed form accordingly.
The customer may adopt self-billing from the date of submission of the form, based on its declaration that all conditions have been met. No further approval from IRAS is required.
If you have previously received IRAS' approval for self-billing, you may continue to self-bill as long as you satisfy the conditions in the form. You are not required to submit the form again.
You are also not required to submit an updated list of suppliers covered under the self-billing arrangement. However, you must retain the updated list as part of your business records.
Under self‑billing arrangements, both supplier and customer remain responsible for ensuring GST is correctly charged, documented and accounted for.
Self-billing tax invoice must have all the following details:
| Details | Example(s) |
|---|---|
| Must state "Buyer Created Tax Invoice" in a prominent place | Buyer Created Tax Invoice – Approved by the Comptroller of GST |
| Invoice identifying number | INV-001 |
| Date of issue of the invoice | 15 Jan 2026 |
| Supplier’s name | ABC Pte Ltd |
| Supplier’s address | 123 Main St |
| Supplier’s GST registration number | GST: 123456789A |
| Customer’s name | XYZ Company |
| Customer’s Address | 456 Business Ave |
| Description of goods/services supplied | Office supplies |
| GST Rate | 9% |
| Total amount payable excluding GST | $100.00 |
| GST amount | $9.00 |
| Total amount payable including GST | $109.00 |
| A statement to inform supplier to account for GST shown as his output tax | The Tax shown is your output tax due to the Comptroller of GST. |
Self-billing customer accounting tax invoice must have all the following details:
| Details | Example(s) |
|---|---|
| Must state "Buyer Created Tax Invoice" in a prominent place | Buyer Created Tax Invoice – Approved by the Comptroller of GST |
| Invoice identifying number | INV-001 |
| Date of issue of the invoice | 15 Jan 2026 |
| Supplier’s name | ABC Pte Ltd |
| Supplier’s address | 123 Main St |
| Supplier’s GST registration number | GST: 123456789A |
| Customer’s name | XYZ Company |
| Customer’s Address | 456 Business Ave |
| Description of goods/services supplied | Office supplies |
| GST Rate | 9% |
| Total amount payable excluding GST | $100.00 |
| GST amount | $9.00 |
| Total amount payable including GST | $109.00 |
| A statement to inform supplier to account for GST shown as his output tax | The Tax shown is your output tax due to the Comptroller of GST. |
| A statement to inform supplier that you (i.e. the customer) will account for this GST shown as your output tax, on his behalf | Sales made under Customer accounting. We will account for the GST shown. |
Understanding invoicing requirements
Unsure of what information you are required to show on your billing documents? Watch our video as we explore the 3 most common billing documents and their invoicing requirements and share tips to help you stay compliant.