Here’s a simple example of how it works.
Say you had £1,000 tucked away in a savings account with a 2% interest rate. After one year, you might earn interest of £20, giving you an updated balance of £1,020.
But in the second year, you’d see the effects of compounding. You’d start to earn interest on your new, higher balance, which now includes the £20.
So, assuming everything stayed the same, your next interest payment would be £20.40 instead. And this would continue to increase as the years went by.