Bond repayment calculator
Your monthly home loan repayment at today’s prime rate (10.75%, SARB · 19 Oct), what the bond costs over its life, and how much a little extra each month saves.
How it’s worked out
South African bonds charge interest monthly on what you still owe. The repayment is the fixed amount that pays the bond off exactly over the term: loan × r ÷ (1 − (1 + r)−n), where r is the yearly rate divided by 12 and n the number of months.
Paying extra goes straight off the capital, so every later month’s interest is smaller. That is why a small extra amount shortens the bond by years.
For planning only, not financial advice. Banks, bond originators and conveyancers will give you exact figures for your situation.