How this calculation works
We grow your starting balance at a nominal annual rate divided into monthly periods. For monthly rate r and n months, the required end-of-month contribution is max(0, target − initial × (1+r)^n) × r / ((1+r)^n − 1). At zero interest it is the unfunded target divided by n. Contributions round up to the next cent.
A worked example
A R24 000 goal, R12 000 starting balance and 12 months at 0% require R1 000 per month. If R12 000 already covers a R10 000 target, the required contribution is zero.
Assumptions & limitations
- Contributions are made at month end; the return stays constant.
- Taxes, fees, withdrawals and product restrictions are excluded; returns are not guaranteed.
- The suggested contribution is rounded up to avoid a rounding shortfall. A starting balance that grows to the goal can require no further contributions.
