How South Africa's legal interest limits actually work, in plain language.
These explain the rules in the National Credit Act that decide how much interest a lender may charge. They cover how the caps are structured and which one applies to a given agreement. Working out the actual figure for a specific agreement needs the repo rate on the day it was concluded, which is what the loan check API is for.
There is no single number. The limit depends on what kind of credit you took, and on the day you signed.
The cap that applies to you depends on this, and getting the category wrong changes the answer completely.
Short-term credit is capped per month, not per year, and the limit falls if you take a second loan in the same calendar year.
The cap locks to the repo rate on the day the agreement was concluded. It does not move afterwards, and using today's rate gives the wrong answer.
A rate calculation tells you one thing. Here is what it does and does not establish, and who to take it to.