Compound interest calculator

• Every period returns exactly the same, and gains are added to the capital before the next one. That doesn't happen in trading: there are good, bad and very bad periods. It's the math of an assumption, not a forecast.
• Contributions are added at the end of each period, so they start earning in the next one.
• Taxes and fees aren't included. To factor them in, subtract them from each period's return.
• The yearly equivalent is the same return compounded over a full year: 1 % a month isn't 12 % a year, it's 12.68 %.

Earning on what you've already earned. If 1,000 returns 10 % and you reinvest, in year two the 10 % is calculated on 1,100, not 1,000. Over time, that difference is what matters most.

Very rarely, and only for a short time. Compounded, it multiplies your capital by more than 37 in a year. The calculator warns you when what you enter goes past 100 % a year.

You can enter a negative return to see a recurring loss. A loss weighs more than a gain of the same size: after losing 50 %, you need to gain 100 % to get back to where you started.