Post Judgment Interest in Singapore: Late Invoices, Court Awards and the 5.33% Rate

Short answer: You can charge interest on a late invoice in Singapore only if the customer agreed to it. Otherwise, interest before judgment is at the court’s discretion under section 12 of the Civil Law Act 1909. After judgment, the debt carries simple interest at 5.33% a year under the Rules of Court 2021 unless another rate was agreed.

Post judgment interest in Singapore, contractual late-payment interest and pre-judgment interest are three different things, and business owners often mix them up when chasing an overdue customer. This guide explains each one, where the rate comes from, how interest is claimed and what to change in your invoices and terms so that it is recoverable.

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 types of interest can a Singapore business claim on an unpaid debt?

There are three types: contractual interest that your terms say the customer must pay, pre-judgment interest that a court may award for the period before judgment, and post-judgment interest that runs on the judgment sum until it is paid. Which ones you can claim depends mainly on what your contract says.

Agreed contractual interest is claimable as of right. Pre-judgment interest (awarded for the period before judgment) compensates a creditor kept out of its money. Post-judgment interest (on the judgment sum until payment) is set by the Rules of Court 2021, the procedural rules for civil cases in the Supreme Court and the State Courts.

What is the legal basis for interest on debts and judgments?

The main sources are section 12 of the Civil Law Act 1909 for pre-judgment interest and Orders 6, 17 and 21 of the Rules of Court 2021 for default judgments, post-judgment interest and interest on costs. The Supreme Court Practice Directions 2021 explain how the rates are applied in practice.

• Section 12(1) of the Civil Law Act 1909 lets the court include interest at such rate as it thinks fit in a judgment for a debt or damages. Section 12(2) says this power does not authorise interest on interest and does not apply where interest is already payable as of right, for example under an agreement.
• Order 6, Rules 6(7) and 7(8) of the Rules of Court 2021 cover interest on default judgments; Order 17, Rule 5 covers post-judgment interest; Order 21, Rule 29 covers interest on costs.
• Paragraph 109 of the Supreme Court Practice Directions 2021 sets out how interest must be stated in a draft default judgment.

The Rules of Court 2021 came into operation on 1 April 2022 and apply to civil proceedings in the Supreme Court and the State Courts commenced on or after that date. Older cases may still be governed by the revoked rules under the transitional provisions.

Can you charge interest on a late invoice in Singapore?

Yes, but only if the customer agreed to it before or when the contract was made. A late-payment clause printed for the first time on an invoice sent after the work is done may not form part of the contract at all.

The safest place for an interest clause is the document the customer signs or accepts before work starts: the quotation, order form, services agreement or online terms. An invoice can repeat the term, but it is usually too late to introduce it there.

The rate must also be defensible. In Denka Advantech Pte Ltd v Seraya Energy Pte Ltd [2020] SGCA 119 (unreported), the Court of Appeal kept the traditional test for penalty clauses: a sum payable on breach is enforceable only if it is a genuine pre-estimate of the likely loss, assessed at the time of contracting. A late-payment rate that is plainly out of proportion to the creditor’s cost of being kept out of its money risks being struck down as a penalty, leaving you with only what the court chooses to award. A rate that tracks your real borrowing cost, plus a reasonable margin, is easier to defend. Our guide to liquidated damages and the penalty rule explains the test in more detail.

When will a Singapore court award pre-judgment interest?

Where there is no contractual rate, pre-judgment interest is at the court’s discretion, and you must ask for it in your statement of claim.

Under section 12(1) of the Civil Law Act 1909 the court decides both the rate and the period, which can start as early as the date the cause of action arose (usually the date payment fell due). On a default judgment the Rules of Court 2021 fix the approach more tightly: the rate is 5.33% a year and the period runs from the date of the originating process (the document that starts the court case) to the date of judgment. Paragraph 109(2) of the Supreme Court Practice Directions 2021 confirms this, and adds that the total amount of interest need not be specified in the draft judgment.

Where a contractual rate applies, paragraph 109(3) requires the rate to be stated, the period to end on the date of judgment rather than payment, and evidence of the agreed rate to be attached to the draft judgment. Because section 12 does not allow interest on interest, compound interest is recoverable only if the contract provides for it.

What is the post judgment interest rate in Singapore?

The default post-judgment interest rate in Singapore is simple interest at 5.33% a year under Order 17, Rule 5 of the Rules of Court 2021. If the parties agreed a different rate in their contract, money payable under the order carries the agreed rate instead.

Order 17, Rule 5 sets four rules:

1. Money payable under an order carries interest as agreed between the parties or, if there is no agreement on interest, simple interest at 5.33% a year.
2. Interest is calculated from the date the order is made until the date of payment.
3. Where the court allows payment by instalments, interest is calculated from the date each instalment is due until it is paid.
4. Part payments must be used to reduce the principal before interest.

The fourth rule surprises many creditors: a part payment goes against the principal first, so interest then runs on a smaller balance. Costs ordered by the court carry their own interest at 5.33% a year under Order 21, Rule 29, although costs under Part 4 of Appendix 1 to Order 21 carry no interest.

Worked example (simple interest, no contractual rate, no part payments):

Interest does not run forever. Under section 6(3) of the Limitation Act 1959, an action on a judgment cannot be brought more than 12 years after it became enforceable, and arrears of interest on a judgment debt cannot be recovered more than 6 years after the interest became due.

How do you claim interest on an unpaid invoice, step by step?

Claim interest at every stage: in the demand, the pleadings and the judgment.

1. Check the contract for the due date and interest clause, and how the customer accepted it.
2. Calculate the interest to date using the agreed rate and method, and keep the working.
3. Send a demand. Your letter of demand should state the principal, the interest claimed, the basis for it and a deadline. Order 5, Rule 1 of the Rules of Court 2021 gives parties a duty to consider amicable resolution and, unless there are reasonable grounds not to, to make an offer of amicable resolution before starting a claim.
4. Instruct a lawyer to file the claim in the right forum (see how to sue a company in Singapore). Court proceedings are conducted by a Singapore Advocate and Solicitor. The statement of claim should plead the contractual rate or ask for interest under section 12 of the Civil Law Act 1909.
5. Obtain judgment. If the defendant does not respond, a default judgment can include contractual interest to the date of judgment, or interest at 5.33% a year from the originating process. A defended claim may end in summary judgment or trial.
6. Track post-judgment interest. From the date of the order, interest runs at the agreed rate or 5.33% simple a year. Apply part payments to principal first.
7. Enforce if unpaid, claiming accrued interest through the enforcement process.

What documents and costs are involved in claiming interest?

You need proof that interest was agreed, proof of the debt and a clear calculation. Claiming interest costs little extra; the cost drivers are those of the debt claim itself.

Assumptions: a commercial debt claim between two companies, served in Singapore. Check current court fees with your solicitor before budgeting.

What does the company secretary prepare and what does the solicitor file?

Your company secretary or corporate service provider keeps the records and paperwork behind the claim; your solicitor drafts and files every court document. Raffles Corporate Services does not act in court or give legal advice.

• The company secretary or CSP can prepare the board resolution authorising legal action, retrieve signed contracts and accepted terms from the company’s records, and confirm who has authority to sign the supporting affidavit.
• The accounts team or bookkeeper prepares the statement of account and interest calculation.
• The solicitor advises on the claim, drafts the statement of claim and any application, files through the court’s electronic filing system and handles enforcement.

After judgment, no ACRA lodgement is needed simply because your company has obtained a judgment for a debt. The accounting still matters: interest awarded should be recorded, and if the debtor cannot pay, the receivable may need a provision. Our guide to provisioning for bad debts and writing off receivables covers that step.

How should you draft invoices and terms so interest is recoverable?

Put a clear interest clause in the terms the customer accepts before work starts, make the rate reasonable and specific, and repeat it on every invoice. Then apply it consistently.

1. State a fixed due date, such as “within 30 days of the invoice date”, not “prompt payment”.
2. State the rate and method, for example “simple interest at X% a year on overdue sums, calculated daily from the due date until payment, before and after judgment”. The words “before and after judgment” show the rate is meant to continue under Order 17, Rule 5(1)(a).
3. Say expressly if interest compounds; otherwise it will not.
4. Choose a rate you can justify by your financing cost, to reduce penalty risk.
5. Get the terms accepted in writing: a signed quotation, a purchase order referring to your terms, or a recorded online acceptance.
6. Repeat the interest term and due date on every invoice and statement.
7. Have a lawyer review the full terms, including any clause on collection costs.

Common mistakes:

• Introducing an interest clause for the first time on the invoice.
• Choosing a rate such as 5% a month that is hard to justify as a genuine pre-estimate of loss.
• Forgetting to plead interest, or claiming contractual interest to the date of payment in a default judgment.
• Applying part payments to interest first after judgment, contrary to Order 17, Rule 5(4).
• Leaving a judgment unenforced until arrears of interest are time-barred.
• Losing the signed terms, so the agreed rate cannot be proved.

If you are unsure whether your existing terms would stand up, speak to a lawyer before your next large contract. Our free tools can also help with related compliance tasks, and our sister site Singapore Secretary Services covers company secretarial record-keeping.

Frequently asked questions

Is the 5.33% post-judgment rate simple or compound interest?

It is simple interest. Order 17, Rule 5(1)(b) of the Rules of Court 2021 provides for simple interest at 5.33% a year where the parties have not agreed a rate. Compound interest is only payable if the contract provides for it.

Can I claim my contractual rate after judgment instead of 5.33%?

Order 17, Rule 5(1)(a) provides that money payable under an order carries interest as agreed between the parties. If your contract sets a rate that applies after judgment, ask your solicitor to plead it and seek it in the judgment.

Can I add interest to an invoice if my terms say nothing about it?

You cannot impose interest the customer never agreed to. You can still ask the court for pre-judgment interest under section 12 of the Civil Law Act 1909 if you sue, but the rate and period are at the court’s discretion.

From when does pre-judgment interest run on a default judgment?

For non-contractual interest, from the date of the originating process to the date of judgment, at 5.33% a year under Order 6, Rules 6(7) and 7(8). For contractual interest, the period is as pleaded but must end on the date of judgment.

Does interest apply to legal costs awarded by the court?

Yes. Under Order 21, Rule 29, assessed, fixed and agreed costs carry interest at 5.33% a year from the relevant date until payment.

Last reviewed: 24 October 2026. The Editorial Team, Raffles Corporate Services.