01
Principal
Principal is the initial amount placed into an investment or interest-bearing account before future interest is added.
COMPOUND INTEREST CALCULATOR
See How Compound Interest Can Grow Your Money Over Time
Calculate the potential future value of your money using an initial investment, regular contributions, interest rate, compounding frequency and investment period.
01
Starting Balance
02
Interest & Compounding
03
Future Value
COMPOUND GROWTH
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CALCULATOR
Your projected compound growth will appear here.
COMPOUND INTEREST CALCULATOR
Calculate compound interest using your own numbers
Enter your investment assumptions below to estimate how your money could grow through compound interest. Results update automatically whenever you change an input.
CALCULATION INPUTS
Build your compound growth scenario
$
$
%
years
Please enter a starting amount or regular contribution, along with
an interest rate and investment period.
The calculator provides an estimate based on the assumptions entered. Actual returns can vary over time.
ESTIMATED COMPOUND GROWTH
Future Value
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Enter your details to calculate
Initial Investment
—
Total Contributions
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Total Interest
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Investment Period
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VALUE BREAKDOWN
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Your Money
Interest Earned
Important:
This calculator is for educational purposes and does not guarantee
investment returns. Taxes, fees, market conditions and actual
investment performance may affect your results.
UNDERSTANDING COMPOUND INTEREST
What is compound interest?
Compound interest is the process of earning interest on an original amount of money as well as on interest that has already been added to the balance.
Unlike simple interest, where interest is calculated only on the original principal, compounding allows previously earned interest to become part of the balance used for future calculations.
02
Interest
Interest represents the amount earned based on the applicable interest rate and the balance used for the calculation.
03
Time
More compounding periods can give accumulated interest more opportunities to become part of the balance.
HOW TO USE THE CALCULATOR
Calculate compound growth in four simple steps
Use realistic assumptions and adjust them to compare different saving and investing scenarios.
01
Enter Your Starting Amount
Add the amount you plan to start with. If you are beginning without an initial balance, you can enter zero and use regular contributions.
02
Add Regular Contributions
Enter the amount you expect to add regularly and select how often those contributions will be made.
03
Choose the Interest Rate
Enter an annual interest assumption. You can change this figure to compare different potential growth scenarios.
04
Set the Time Period
Select the number of years the money is expected to remain invested and review the projected future value.
COMPOUND INTEREST FORMULA
How compound interest is calculated
The basic compound interest formula calculates the future value of an initial principal after repeated periods of compounding.
A = P × (1 + r/n)nt
The formula applies to a principal amount without additional
recurring contributions.
A represents the future value, P is the principal, r is the annual interest rate, n is the number of compounding periods per year, and t represents time in years.
A
Future value
P
Initial principal
r
Annual interest rate
n
Compounding frequency
t
Time in years
COMPOUNDING FREQUENCY
COMPOUNDING FREQUENCY
How often interest is added can affect the result
Compounding frequency refers to how often interest is calculated and added to an account during a year.
Annual, semiannual, quarterly, monthly and daily compounding are common structures. With the same nominal annual rate and all else equal, more frequent compounding can produce a different ending balance.
Annual
1 compounding period per year
Quarterly
4 compounding periods per year
Monthly
12 compounding periods per year
Daily
365 compounding periods per year
WHY COMPOUNDING MATTERS
Small changes can have a large long-term effect
Compound growth is influenced by more than the interest rate alone. Your starting balance, contributions and time horizon all matter.
Starting Balance
A larger starting balance means more capital is exposed to the assumed rate of return from the beginning.
Regular Contributions
Adding money consistently can increase the amount available to participate in future compound growth.
Interest Rate
The assumed annual rate has a direct effect on the amount of interest generated by the calculation.
Time Horizon
A longer period gives interest more opportunities to compound, although investment outcomes are never guaranteed.
Compounding Frequency
The frequency with which interest is calculated and added can influence the ending balance.
Taxes and Fees
Real-world results can differ from calculator projections because of taxes, account costs and investment expenses.
COMPOUND VS SIMPLE INTEREST
Understand the difference between the two
Simple interest is generally calculated only on the original principal. Compound interest allows previously earned interest to become part of the balance used for future interest calculations.
01
Simple Interest
Interest is calculated on the original principal over the applicable period.
I = P × r × t
- Interest is based on principal
- Does not compound previous interest
- Useful for straightforward interest calculations
02
Compound Interest
Interest can be added to the balance and subsequently earn additional interest.
A = P × (1 + r/n)nt
- Interest can earn additional interest
- Compounding frequency affects the calculation
- Time can have a significant effect
COMMON MISTAKES
Avoid unrealistic compound growth assumptions
Assuming a Constant Return
Real investments can rise and fall. A calculator uses the rate you enter and does not predict actual market performance.
Ignoring Taxes and Fees
Taxes, account costs and investment expenses can reduce the amount of money that remains available for growth.
Underestimating Time
Shortening or extending the investment period can materially change a compound-growth projection.
Focusing Only on the Final Balance
Review the starting amount, contributions, interest and assumptions rather than looking only at the projected ending value.
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COMPOUND INTEREST FAQ
Questions about compound interest
Compound interest is interest earned on an initial amount plus previously accumulated interest. This can allow the balance to grow at an increasing rate over time.
The calculator applies compound-growth mathematics to the inputs you provide, including the starting balance, interest rate, compounding frequency and investment period.
No. The calculator produces a mathematical projection based on the rate entered. Actual investment returns can differ substantially and are not guaranteed.
Compounding frequency determines how often interest is calculated and added to the balance. Different frequencies can produce different future values when other assumptions remain the same.
Yes. This calculator allows you to include recurring contributions and choose a monthly, quarterly or annual contribution schedule.
A longer timeframe provides more compounding periods. When returns remain invested, previously accumulated interest can participate in future growth.
START WITH YOUR OWN NUMBERS
Calculate Now
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See what compound interest could mean for your future balance
Enter your assumptions above and explore how starting capital, contributions, interest and time can affect the projection.