MinuteMetric

Making Sense of the Numbers

Almost every personal finance question comes down to the same handful of mechanics: compound growth, amortisation, and the difference between what something costs per month and what it costs in total. The calculators here make those mechanics visible, so you can compare options on the numbers rather than on how they're presented to you.

Compounding is the idea underneath most of them. Money that earns a return generates further returns on those returns, which is why time in the market matters so much for saving — and why high-interest debt is so corrosive when left to run. The same formula drives both; only the direction changes.

Questions Worth Asking

• What's the total cost, not the monthly payment? Stretching a loan over a longer term lowers the monthly figure and raises the total substantially. Lenders quote the number that sounds smallest.
• Is the rate fixed or variable? A projection built on today's rate can look very different after a change. Try the calculation again at a higher rate to see how much headroom you have.
• What's the real return? Inflation erodes nominal returns. A 4% return with 3% inflation is a 1% gain in purchasing power.
• What are the fees? Ongoing percentage fees compound against you exactly as returns compound for you, and small percentages become large sums over decades.

These tools give general estimates using standard formulas. They aren't financial advice and can't account for your tax position, circumstances or goals — for decisions of any size, speak to a qualified adviser.