When someone owes you money (whether from an unpaid invoice, a breach of contract, or a court award) waiting months or years to get paid has a real financial cost. In South Africa, mora interest (often referred to informally as court interest) is the legal mechanism designed to compensate you for that delay.
What Is Mora Interest and Why Does It Exist?
In legal terms, mora means “delay” or “default”. Mora interest is not a fee you agreed to pay for borrowing money, like interest on a home loan or credit card. Instead, it is compensation that the law awards to a creditor when a debtor fails to pay money on time.
The principle is straightforward: if you were entitled to money on a specific date and didn’t receive it, you lost the opportunity to use or invest those funds. South African courts do not require you to prove exactly what return you would have earned had you been paid on time. Simply being kept out of your money is enough to justify compensation.
Example: Suppose a freelance designer completes a project and sends an agreed invoice for R20,000 due at the end of the month. If the client ignores the invoice and only pays six months later, mora interest compensates the designer for the six-month delay.
Mora Interest vs. the Prime Rate and Repo Rate
People frequently confuse mora interest with the prime lending rate (the benchmark rate commercial banks charge their customers) or the repo rate (the interest rate at which the South African Reserve Bank lends money to commercial banks).
Mora interest is distinct from both:
It is set by statute, not banks. Where a contract does not specify its own late-payment interest rate, the default mora rate (known as the prescribed rate of interest) is governed by the Prescribed Rate of Interest Act 55 of 1975.
How mora relates to the repo rate? Under current law, the prescribed mora rate is calculated as the South African Reserve Bank (SARB) repo rate plus 3.5% per year.
When rate changes take effect? Unlike bank loans that adjust almost immediately after a Reserve Bank announcement, the prescribed mora rate only changes on the first day of the second month following the month in which SARB adjusts the repo rate. For instance, if the Reserve Bank changes the repo rate in September, the new prescribed mora rate takes effect on 1 November.
The “locked-in” rate rule:- In most cases, the prescribed rate that applies on the day interest starts running remains fixed for the entire duration of that debt, even if the repo rate goes up or down later – unless an agreement, specific statute, or court order states otherwise.
South Africa · 1976–2026
Prime, repo and mora interest rates
Show table Hide table
Rates at 31 December each year, except 2026, which is shown as at 6 November 2026. All rates are percentages per annum.
| Year | Prime | Repo | Moraprescribed |
|---|---|---|---|
| 1976 | 12.50% | — | 11.00% |
| 1977 | 12.50% | — | 11.00% |
| 1978 | 11.50% | — | 11.00% |
| 1979 | 9.50% | — | 11.00% |
| 1980 | 9.50% | — | 11.00% |
| 1981 | 17.00% | — | 11.00% |
| 1982 | 18.00% | — | 11.00% |
| 1983 | 20.00% | — | 11.00% |
| 1984 | 24.00% | — | 11.00% |
| 1985 | 16.50% | — | 20.00% |
| 1986 | 12.00% | — | 15.00% |
| 1987 | 12.50% | — | 12.00% |
| 1988 | 18.00% | — | 12.00% |
| 1989 | 21.00% | — | 18.50% |
| 1990 | 21.00% | — | 18.50% |
| 1991 | 20.25% | — | 18.50% |
| 1992 | 17.25% | — | 18.50% |
| 1993 | 15.25% | — | 15.50% |
| 1994 | 16.25% | — | 15.50% |
| 1995 | 18.50% | — | 15.50% |
| 1996 | 20.25% | — | 15.50% |
| 1997 | 19.25% | — | 15.50% |
| 1998 | 23.00% | 19.30%* | 15.50% |
| 1999 | 15.50% | 12.00% | 15.50% |
| 2000 | 14.50% | 12.00% | 15.50% |
| 2001 | 13.00% | 9.50% | 15.50% |
| 2002 | 17.00% | 13.50% | 15.50% |
| 2003 | 11.50% | 8.00% | 15.50% |
| 2004 | 11.00% | 7.50% | 15.50% |
| 2005 | 10.50% | 7.00% | 15.50% |
| 2006 | 12.50% | 9.00% | 15.50% |
| 2007 | 14.50% | 11.00% | 15.50% |
| 2008 | 15.00% | 11.50% | 15.50% |
| 2009 | 10.50% | 7.00% | 15.50% |
| 2010 | 9.00% | 5.50% | 15.50% |
| 2011 | 9.00% | 5.50% | 15.50% |
| 2012 | 8.50% | 5.00% | 15.50% |
| 2013 | 8.50% | 5.00% | 15.50% |
| 2014 | 9.25% | 5.75% | 9.00% |
| 2015 | 9.75% | 6.25% | 9.00% |
| 2016 | 10.50% | 7.00% | 10.50% |
| 2017 | 10.25% | 6.75% | 10.25% |
| 2018 | 10.25% | 6.75% | 10.00% |
| 2019 | 10.00% | 6.50% | 10.00% |
| 2020 | 7.00% | 3.50% | 7.00% |
| 2021 | 7.25% | 3.75% | 7.00% |
| 2022 | 10.50% | 7.00% | 9.75% |
| 2023 | 11.75% | 8.25% | 11.75% |
| 2024 | 11.25% | 7.75% | 11.50% |
| 2025 | 10.25% | 6.75% | 10.50% |
| 2026† | 10.75% | 7.25% | 10.75% |
When Does Mora Interest Start Running?
You cannot simply add interest from the day an accident happened or a dispute began.
When the interest clock starts ticking depends on the type of debt involved:
1. Fixed or Easily Calculable Debts (“Liquidated” Debts)
A liquidated debt is an amount that is already fixed or can be easily calculated – such as an unpaid invoice for an agreed price.
When there is an agreed due date (mora ex re): If a contract or invoice states payment is due on 31 March, the debtor is automatically in default on 1 April. Interest runs from that date without any further notice required.
When there is no fixed due date (mora ex persona): If no payment date was set, the creditor must send a formal written demand giving a reasonable deadline to pay. Interest starts running once that deadline passes.
2. Disputed Damages That Require Assessment (“Unliquidated” Debts)
An unliquidated claim is one where the exact rand amount is unknown until a court assesses it – such as damages for pain and suffering or loss of income.
The general starting rule: Interest typically begins from the earlier of a formal written demand (containing enough detail for the other party to reasonably assess the claim) or the service of a court summons.
Future losses and general damages: If a court awards money for losses that have not happened yet (like future lost earnings) or calculates non-financial harm (like pain and suffering) using current money values at the time of judgment, interest generally runs only from the date of judgment. Charging interest from an earlier date on an award already priced in today’s money would overcompensate the claimant.
Road Accident Fund (RAF) claims: Special rules apply to the RAF. Under the Road Accident Fund Act, the RAF enjoys a 14-day interest-free grace period following a court order, meaning interest only starts running on day 15.
3. Judgment Debts
Once a court orders a party to pay a specific amount, it becomes a judgment debt. Post-judgment mora interest runs automatically from the date of judgment (or day 15 for RAF awards) until the debt is paid in full – even if the court order itself does not explicitly mention interest.
How to Calculate Mora Interest
Mora interest is ordinarily calculated as simple interest, not compound interest. This means interest is calculated only on the unpaid principal amount, rather than charging interest on top of unpaid interest every month.
The standard formula uses the actual number of days late divided by 365:
Worked Example
Imagine a court orders a defendant to pay R100,000, the applicable prescribed rate is 10.75% per year, and the defendant pays 180 days after interest begins to run:
Calculate annual interest: R100,000 x 10.75% = R10,750 per year
Calculate daily interest: R10,750 / 365 = R29.45 per day
Multiply by days late: R29.4521 x 180 days = R5,301.37
Unpaid capital: R100,000
Mora interest (180 days): R5,301.37
Total payable: R105,301.37
(Note: If this were a Road Accident Fund judgment paid 180 days after the court order, you would first subtract the 14-day interest-free period, leaving 166 interest-bearing days.)
Vector Actuaries · South Africa
Mora interest calculator
Estimate simple interest on an unpaid balance in rand.
Calculation estimate
Estimated simple interest
- Unpaid amount
- Total with interest
Show calculation details
| Calendar year | Days | Divisor |
|---|
The count includes the start date, weekends and public holidays. The calculator rounds the total interest to the nearest cent.
Other Practical Rules to Keep in Mind
The in duplum rule: Under South African law, unpaid arrear interest generally stops accumulating once it reaches an amount equal to the original unpaid capital. However, courts have recognized important nuances depending on the type of award and the stage of litigation, so it is not an automatic cap in every situation.
Partial payments and settlements: If a debtor makes a partial payment or a formal settlement offer, it can stop or reduce further interest. Whenever you negotiate a settlement, make sure the agreement explicitly states whether the settlement figure includes or excludes accrued interest, and specify exact payment deadlines.
Disclaimer: This primer provides general information on South African law. How mora interest applies to a specific claim depends on the facts of the matter, any underlying contract, relevant legislation, and the wording of any court order.