# Compound Interest Calculator

Use this compound interest calculator to see how how much your investments now can pay off over time with compound interest. You can adjust the initial investment, add additional monthly and yearly payments (or withdrawals), adjust the expected APY (annual percent yield), and set a number of years into the future to see how investments look over time. See how changes to investments (or withdrawals) and increasing or decreasing interest rates affect your savings.

**How does compound interest work?** Compound interest occurs when interest
gets added to the principal amount invested or borrowed, and then the
interest rate applies to the new (larger) principal. It's essentially
interest on interest, which over time leads to exponential growth.

**Things to keep in mind when using this calculator.**
This calculator assumes deposits/withdrawals are made on the first day of the
term. ie. monthly contributions are made on the first day of the month,
and additional annual contributions are made on the first day of the year.
For the "Summary Charts" section, hover over charts (or touch them if
you're on a mobile device) to see details about that part of the chart.
The "Summary Charts" and "Interest Tables" sections are collapsible
if you click (or touch) those section headers.