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Both tools update as you type. They are grounded estimators for the statutory ceilings — not a statement of account, and not legal advice. Figures verified 26 June 2026.
1. Maximum interest rate
The Regulation 42(1) Table A caps. For repo-linked types the cap is the reference (repo) rate plus a fixed margin, set at the date the credit is granted.
Use the repo rate in force when the credit was granted. Default 6.75% is the rate implied by the prescribed rate of interest as at 1 March 2026; confirm the current repo rate before relying on a figure.
Maximum lawful interest
18.75% per year
6.75% repo + 12% — the cap for a mortgage agreement under Table A.
Interest is only one component of the cost of credit. A monthly service fee (capped at R60 per month), an initiation fee, credit insurance, default administration charges and collection costs are separately capped under s 101 and the regulations.
2. In duplum ceiling checker
The in duplum rule stops accumulated charges exceeding the capital. The statutory rule (s 103(5)) applies to NCA agreements; the common-law rule applies to debts outside the Act.
How the maximum-rate cap works
Section 101 lists the only charges a credit provider may levy, and pegs interest to a maximum prescribed rate. Section 105 empowers the Minister to prescribe those maxima, which appear in Regulation 42(1), Table A.
A credit agreement must not require payment by the consumer of any money or other consideration, except— (a) the principal debt, being the amount deferred in terms of the agreement, plus the value of any item contemplated in section 102; (b) an initiation fee…; (c) a service fee…; (d) interest, which— (i) must be expressed in percentage terms as an annual rate calculated in the prescribed manner; and (ii) must not exceed the applicable maximum prescribed rate determined in terms of section 105; (e) cost of any credit insurance…; (f) default administration charges…; and (g) collection costs…
Mortgage agreements RR + 12% per year. Credit facilities RR + 14% per year. Unsecured credit transactions RR + 21% per year. Developmental credit agreements RR + 27% per year. Short-term credit transactions 5% per month on the first loan and 3% per month on subsequent loans. Other credit agreements RR + 17% per year. Incidental credit agreements 2% per month.
Note — “RR” is the reference rate — the SARB repurchase rate — added once. The maximum is fixed at the date the credit agreement is entered into and does not move with later rate changes.
How the in duplum rule works
There are two in duplum rules running in parallel. The statutory rule in NCA s 103(5) is the wider of the two: it caps all the post-default charges, measured against the principal balance at the date of default.
Despite any provision of the common law or a credit agreement to the contrary, the amounts contemplated in section 101(1)(b) to (g) that accrue during the time that a consumer is in default under the credit agreement may not, in aggregate, exceed the unpaid balance of the principal debt under that credit agreement as at the time that the default occurs.
The common-law rule is narrower — it caps interest only, against the fluctuating outstanding capital — but it reaches debts the NCA never touches, including the large business loans excluded by the R1 000 000 threshold.
The prescribed rate of interest
A separate figure governs mora (late-payment) interest and interest on a judgment debt where no rate is agreed: the prescribed rate of interest under the Prescribed Rate of Interest Act 55 of 1975. It is currently 10.25% per year with effect from 1 March 2026 (SARB repurchase rate + 3.5% (variable; gazetted periodically)). This is the rate that typically applies to a debt outside the NCA where the parties did not fix an interest rate.
Frequently asked questions
For agreements under the National Credit Act, the maximum is set by Regulation 42(1), Table A: the SARB repurchase (repo) rate plus a fixed margin depending on the credit type — mortgages RR + 12% per year, credit facilities RR + 14% per year, unsecured credit RR + 21% per year, developmental credit RR + 27% per year, and other agreements RR + 17% per year. Short-term credit is capped at 5% per month on the first loan, 3% per month on subsequent loans in a calendar year, and incidental credit at 2% per month.
The cap is fixed at the date the credit is granted. Debts outside the NCA are not subject to these caps — only to the agreed interest and the common-law in duplum rule.
The in duplum rule stops arrear interest (and, under the NCA, other charges) from exceeding the unpaid capital. At common law, interest stops running once unpaid interest equals the outstanding capital, and resumes if a payment brings it back below capital (Standard Bank v Oneanate). Under the NCA, s 103(5) goes wider: while the consumer is in default, the interest, fees, credit insurance, default-administration charges and collection costs may not in aggregate exceed the unpaid balance of the principal debt as at the date the default occurred. See interest caps & in duplum.
No. In Paulsen v Slip Knot Investments the Constitutional Court confirmed that the common-law in duplum rule continues to cap interest during litigation — it is not suspended when the creditor issues summons. Interest may resume running only from the date of judgment.