Guides
Plain explanations of what the calculator leaves out — fees, inflation, how interest rates are quoted, and debt — each with worked examples.
The compound interest calculator shows how a balance grows at a steady rate. Real money is affected by more than that. These guides explain the parts that change the outcome most.
Each one works through an example using the same arithmetic as the calculator, starting from the same default amounts, so you can repeat any example there and get the same figures. None of them recommends a product or an investment; they explain how the numbers behave.
How fees compound
A fee of 1% a year sounds small. Over decades it takes a far larger share of the final balance than the percentage suggests. Here is the arithmetic.
Inflation and real returns
A balance that grows 7% a year does not buy 7% more. How to turn a nominal return into a real one, and what inflation does to money over ten and thirty years.
Nominal vs. effective interest rate
Two accounts that both pay 6% can pay different amounts. How compounding frequency turns a nominal rate into an effective annual rate, and why it matters more for loans.
How debt compounds
Interest on unpaid debt grows the same way savings do, only against you. A worked card example shows how much the monthly payment changes the total cost.