South African loan interest is governed by a chain that runs from the Reserve Bank down to your monthly statement. Understanding the chain — the repo rate, the prime rate, and the legal caps in the National Credit Act — tells you whether the rate you’re offered is fair, or even lawful.
The repo rate anchors everything
The repo rate is the Reserve Bank’s policy rate. The Monetary Policy Committee reviews it regularly. It influences borrowing costs but is not your loan’s rate. Check the latest SARB decision instead of treating an old article’s figure as current.
When benchmark rates change, a variable-rate loan linked to prime may change too. A quote of “prime minus 0.5 percentage points” is normally a variable-rate formula, not a fixed interest rate. Confirm the adjustment clause and fixed-rate period in your agreement.
Prime: the benchmark rate
The prime rate is a lending benchmark used by banks. Check the lender’s published benchmark and your contractual margin; neither a margin nor a quoted rate proves that an offer is affordable.
Quotes may use a benchmark or a fixed annual rate. For a fictional prime rate of 10%:
- “Prime plus 3 percentage points” means 13% in this example.
- “Prime minus 0.75 percentage points” means 9.25% in this example.
- Fixed rates — a flat number for the whole term, regardless of repo movements.
The margin (the “plus 3” or “minus 0.75”) reflects your risk as a borrower: credit record, income, deposit size and existing debt. Two people can get different rates from the same bank on the same day.
The National Credit Act caps: repo + a margin
The National Credit Regulations specify maximum rates by credit category. Several use the repo rate plus a margin; short-term and incidental credit use monthly limits. The table below is a regulatory reference, not a personal quote. Verify the applicable category and current regulations with the NCR before challenging a charge; do not assume a repo-linked maximum is frozen for the life of an agreement.
| Credit type | Maximum interest rate |
|---|---|
| Mortgage agreements | Repo + 12% p.a. |
| Credit facilities (credit cards, overdrafts) | Repo + 14% p.a. |
| Unsecured credit transactions (personal loans) | Repo + 21% p.a. |
| Developmental credit agreements | Repo + 27% p.a. |
| Other credit agreements | Repo + 17% p.a. |
| Short-term credit transactions | 5% p.m. first loan, 3% p.m. subsequent (same year) |
| Incidental credit agreements | 2% p.m. |
For a purely hypothetical repo rate of 7%, a repo-plus-21 formula gives 28% annually. That does not mean 28% is today’s limit or an appropriate rate to accept. Ask the NCR to assess suspected overcharging against the relevant agreement and period.
Fees are capped too
Interest isn’t the only cost. The Act also caps the other charges a lender may levy: an initiation fee when the loan is set up, a monthly service fee while it runs, and credit insurance (which the lender must offer with your existing cover in mind, and cannot force you into unnecessary amounts). These sit on top of interest, so always compare the total cost of credit — interest plus fees — not just the rate.
The affordability check
Before a lender can grant credit, the National Credit Act requires an affordability assessment: the lender must verify your income and expenses and may only grant credit that you can reasonably afford to repay. This is why lenders ask for payslips or bank statements — and why you can complain to the National Credit Regulator if a lender approved credit you clearly couldn’t afford.
The in duplum rule caps default charges
Section 103(5) limits the aggregate specified charges accruing during default by reference to the unpaid principal when default began. It is not a blanket rule that every debt can never exceed twice its original loan amount. Nor do payments automatically restart charges once the statutory ceiling has been reached while default continues. Request a dated capital-and-charges breakdown and seek NCR or legal assistance if you suspect a breach. Do not stop paying solely on the basis of a calculator estimate.
Putting it together: reading a quote
A fair loan quote shows you:
- The interest rate, expressed as an annual percentage, and how it relates to prime.
- The fees — initiation, service and insurance — itemised separately.
- The total cost of credit — everything you’ll repay.
- The repayment schedule — every instalment, for the full term.
Run the numbers yourself with the loan repayment calculator to see how much of each instalment is interest, then read how to calculate loan repayments for the principal and interest split inside each payment.
Where to verify
- National Credit Regulator (ncr.org.za) — consumer credit information and complaints.
- South African Reserve Bank (resbank.co.za) — the repo rate and Monetary Policy Committee decisions.
- gov.za — National Credit Act 34 of 2005 — the Act and its regulations.