Compound Interest Calculator

Use this compound interest calculator to project how your savings or investments will grow over time. Enter your starting balance, expected interest rate, and regular monthly contributions to instantly see the difference compounding makes to your long-term returns.

Initial Principal Amount ($):

Annual Interest Rate (%):

Time Period (Years):

Compound Frequency:

Additional Contribution Amount ($):

Contribution Frequency:

Display Breakdown:

Display Type:

Table Graph

What is Compound Interest?

Compound interest is the interest you earn on both your original deposit and on the interest you've already accumulated. Unlike simple interest, which only pays out on your initial principal, compounding reinvests your earnings so your balance grows at an accelerating rate.

Because each interest calculation builds on a new, larger total, your money grows faster over time. This applies whether the interest is calculated daily, monthly, or annually.

Formula source: BBC

How to Make Compound Interest Work for You

To get the most out of compound interest, focus on these fundamental habits:

Start early: The longer your money has to compound, the more significant the growth. Time is the most important factor in compounding.
Invest regularly: Making consistent monthly additions to your principal drastically accelerates your growth curve.
Check the compounding frequency: Look for accounts that compound more often (such as daily or monthly instead of annually) to maximize your yield.
Avoid early withdrawals: Let your money sit and grow uninterrupted so you don't break the compounding cycle.
Reinvest your dividends: If you are investing in stocks or funds, always ensure your payouts are set to automatically reinvest into your principal balance.