Compound Interest Calculator

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How do different growth rates, investment durations, starting values and annual contributions effect your long term investment performance? Now you can find out! With our Interactive Compound Interest Calculator you can compare up to 3 investments, each with different initial values, annual contributions, compound growth rates and time horizons. Check it out: 

To use simply enter up to 3 different starting values, annual contributions, growth rates and durations:

For example, already pre-filled out in the calculator is 3 different investments. Each starts with $5,000 initially, but they have different annual contributions ($5,000, $4,800 and $4,500), growth rates (6%, 5% and 4%) and durations (20, 22 and 25 years). Notice that they all come out to roughly similar totals – even though investment 3 has a much lower growth rate, and has lower annual contributions – showing the importance that your investment horizon has on your performance!

Having trouble? See more detailed instructions and definitions below.


Some terms that may need defining:

Initial Investment – The amount of money to start your investment.

Annual Additions – This is the amount of additional money you contribute to the investment each year.

Growth Rate – This is the rate that your investments grow each year.

Duration – This is how long you let your investment ride.


Like this? Check out our other investing calculators:


Expense Ratio Calculator – How much is that fund’s expense ratio hurting your investment performance? Now you can easily find out. Compare 2 investments with different expense ratios and see the difference!

Asset Allocation Calculator – How has asset allocation historically effected your returns? What is the worst performance an 80/20 stock/bond asset allocation has had? Now its easy to see – so you know what to expect when setting up your portfolio’s asset allocation.



About this calculator:

This uses microsoft excel’s future value formula to calculate the values you see above. Interest is compounded once, at the end of each year.

The results shown by this calculator are for education and entertainment only. It makes many assumptions (such as an investment always goes up the same amount every year!) and therefore should not be used solely to plan for retirement or make any life changing decisions!

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