What car can your income actually carry?

There are three well-known answers to that question and they disagree with each other, sometimes by hundreds of thousands of rand. Running all three at once is more useful than picking a favourite, because affordability is a range and the spread between the strict rule and the loose one is the honest version of the answer.

The three, as applied here. A payment cap keeps the instalment under 15% of take-home pay for a new car, 10% for a used one, with the whole transport bill under 20%. The 20/4/10 rule wants 20% down, a term of 48 months at most, and all car costs under 10% of gross income. The 1/10th rule caps the cash price at a tenth of a year's gross, which reads brutally on purpose. It's a wealth-builder benchmark, not the South African norm.

It works in both directions. From your income it returns the price each rule allows. From a car's price it returns the income each rule wants.

Running costs are counted, which is where this parts company with most calculators. Fuel, insurance and upkeep can rival the instalment, and they're the reason car budgets break. Enter them once on the shared Running costs card and every Auto tool uses them.

Bring your take-home pay and your gross pay, because the payment cap works on take-home while 20/4/10 and the 1/10th rule are written against gross. Then the finance: new or used, the term, your deposit, any balloon, and a rate. Pick your credit band and a realistic rate fills itself in.

The result gives your rule's answer as the headline, all three side by side in a chart, and a transport-share card grading the instalment plus running costs against the 20% all-in ceiling.

These are guidance rules, not a lender's decision. The bond affordability tool runs the legal NCA test; the finance and balloon tool prices an exact deal.

Money Cat is an information tool, not financial advice. Confirm any figure that matters with your bank, lender or a registered professional.