# 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.