About RandMath

Who runs this

RandMath is a small independent site built by one developer in South Africa. It is not a bank, an originator, or a financial services provider, and it does not give financial advice. It does arithmetic, and it tries to do that arithmetic with the correct South African tables instead of importing an American calculator.

Where every number comes from

• Income tax brackets and rebates — the 2026/2027 tables effective 1 March 2026, as announced in the February 2026 Budget: seven brackets from 18% to 45%, primary rebate R17 820, secondary R9 765, tertiary R3 249. Applied as progressive slices, with the rebate deducted from the tax (not from income) and the medical scheme credit at R376 a month for the first two members and R254 for each additional member.
• UIF — 1% of gross, capped at R177,12 a month.
• Transfer duty — the SARS table for transactions on or after 1 April 2025, which sets 0% up to R1 210 000, then 3% / 6% / 8% / 11% / 13% bands with the published base amounts. This is law; it is not an estimate.
• Bond instalments — the standard amortising loan formula, monthly compounding, fixed rate for the term. No fees, no insurance, no rate changes.
• Prime lending rate — 10,75% since 25 September 2026, when the SARB lifted the repo rate to 7,25%. Used only as a default; every calculator lets you change it.

What is an estimate, and what is exact

Real money arithmetic is exact: the instalment formula, the tax slices, the transfer duty bands. If those are wrong, that is a bug and I want to hear about it.

Three things on this site are deliberately uncertain, and labelled as such:

• Attorney and bond registration fees. South African conveyancers quote on a guideline tariff and discount from it. The transfer cost calculator therefore has the percentage as an editable field rather than pretending to know your attorney's number.
• Affordability. A budgeting guideline, not a bank's credit decision. Banks assess on net income and your credit record.
• Your rate. Prime is a reference point. What you are offered depends on your deposit, your credit profile and the lender.

How this site makes money

Two ways, both stated plainly:

1. Referral fees from bond originators. If you submit the quote form, your details go to an FSP-registered originator, and if a bond is eventually registered we may be paid a referral fee by that originator. You pay nothing, and the rate you are quoted is not affected by it.
2. Advertising. Display ads on the calculator pages, once there is enough traffic for them to be worth the page weight.

There is no email list, no paid tier, and nothing behind a login. If a calculator ever gets a "pro" version, this page will say so before you hit it.

Corrections

SARS rebrackets every February and the MPC meets six times a year, so tables go stale. Rates on this site were last checked in October 2026. If you find a figure that no longer matches the source — or arithmetic that is simply wrong — send it to hello@randmath.co.za and it gets fixed, with the correction noted.