What happens if you pay extra into your bond?
Every extra rand goes straight at the capital — and stops being charged interest from that day on. In a worked example, R1,000 extra a month on a R1.5 million bond at an illustrative 11% settles the loan 43 months early and saves R469,883 in interest.
The saving is mechanical, not market-dependent: an extra bond payment reliably "earns" the bond's interest rate, and the saving is not taxed.
The mechanics: why small extras punch so hard
Home loan interest accrues daily on the outstanding balance. An extra payment does not shorten a schedule somewhere in a filing cabinet — it drops the balance the day it lands, and from that day every interest calculation runs on the smaller number. The saving then compounds: less interest means more of every future instalment hits capital, which means less interest again.
This is also why timing matters more than intuition suggests: the same extra rand saves the most interest early in the term, when the balance — and therefore the interest — is at its peak.
The worked example
Take the loan from "What does a home loan really cost over 20 years?": R1.5 million over 240 months at an illustrative 11%, instalment R15,482.83, total interest about R2.22 million.
Now add R1,000 a month — R16,482.83 instead. Simulated month by month:
- The bond settles in month 197 instead of month 240 — 43 months (3 years and 7 months) early
- Total interest falls from about R2.22 million to about R1.75 million
- Interest saved: R469,883 — from R1,000 a month
Notice the asymmetry: the extra paid in over those 197 months is R197,000, and it comes back as R469,883 of interest that never gets charged. The extra payments are not spent — they are capital sitting in the bond instead of a savings account.
A guaranteed rate, and no tax on it
An extra bond payment "earns" the bond's own rate — in the worked example, the illustrative 11% — because that is the rate the money stops being charged. There is no market involved: the saving happens whether shares rise or fall that year.
And there is a second, quieter feature: interest earned in a savings account is taxable income above the annual exemption, while interest *not paid* on a bond is not income at all. Rand for rand, avoiding 11% interest and earning 11% interest are not the same after tax — the avoided interest keeps all of it. How that comparison plays out against investing is covered in "Pay off debt or invest — how does the maths compare?"
Access bonds: the money is not locked away
Many South African home loans offer an access facility: extra payments remain withdrawable, because they sit as prepaid balance rather than a separate account. In practical terms, the bond can function like a savings account paying the bond rate — the money reduces interest while it sits there, and can be taken back out if the geyser bursts.
The facility's terms differ by bank — some require registration upfront, some have minimum withdrawal amounts — so the specifics live in the loan agreement, not in a general article.
What the numbers do not say
The arithmetic above says what an extra payment does — not whether it beats every alternative use of the same R1,000. That depends on the interest rate of other debts, what an investment might earn, and what tax does to each. The sibling article on debt-versus-investing walks that comparison; this one establishes the baseline it gets compared against: a guaranteed, tax-free, bond-rate return.
Terms used on this page
- compounding
- Growth on growth: returns earn their own returns. It is why time in the market matters more than the size of any single deposit.
Reviewed July 2026