See How Your Money Could Grow Through Compounding.
Calculate potential compound interest growth using your own starting amount, regular contributions, interest rate and investment period. Explore how compounding can affect your savings or investments over time.
Enter Your Figures
Use your own numbers to calculate a personalised compound interest projection. Nothing is pre-filled.
Potential Future Value
This calculator provides an illustrative mathematical projection. Actual savings and investment returns can vary, and interest may not be fixed.
What Is Compound Interest?
Compound interest is interest calculated on an amount that includes previously accumulated interest. Instead of growth being calculated only on the original amount, previous interest can also contribute to subsequent growth.
Your Starting Amount
The initial amount provides the starting capital on which future compound growth can be calculated.
Regular Contributions
Additional contributions increase the amount of capital that can potentially benefit from future compounding.
Interest Rate
The assumed interest rate directly influences how quickly the mathematical projection grows over time.
Time Horizon
A longer period gives compound growth more opportunity to build on previously accumulated interest.
Compounding Frequency
Interest can be calculated at different frequencies. More frequent compounding can change the mathematical outcome.
Growth on Growth
The key feature of compounding is that accumulated interest can itself become part of the amount used for future calculations.
How Compound Interest Is Calculated
The standard compound interest formula for a lump sum is used to calculate the future value of an amount when interest is compounded at regular intervals.
P represents the principal amount, r represents the annual interest rate, n represents the number of compounding periods per year and t represents the number of years.
When regular contributions are included, the calculation also accounts for additional money being added during the investment period.
Calculation Summary
Your summary will update after you calculate the projection above.
See How Different Interest Rates Can Affect Growth
Once you calculate your result, these scenarios use your own amount, contributions and time period to show how different assumed interest rates can change the mathematical projection.
4% interest
A lower assumed rate can demonstrate a more conservative compound-growth projection.
7% interest
A mid-range assumption helps demonstrate the effect of changing the rate over a longer period.
10% interest
A higher assumed rate can create a significantly different mathematical projection over time.
Four Factors That Can Influence Compound Growth
Compound growth is affected by more than the interest rate alone. Understanding the relationship between these factors can make projections easier to interpret.
Starting Capital
The amount you begin with determines the initial base from which compound growth is calculated.
Regular Additions
Consistent contributions can increase the amount available to generate potential future interest.
Time
The longer money remains invested or saved, the more opportunities there may be for accumulated interest to compound.
Rate & Frequency
The assumed rate and frequency at which interest is compounded both affect the mathematical result.
Use Compound Interest Calculations as a Planning Tool
Compound interest calculations can help you understand how money may grow under a particular set of assumptions. They are useful when comparing different savings or investment strategies.
However, a mathematical projection should not be treated as a promise of future returns. Real interest rates and investment performance can change, while fees, inflation and taxation may affect the amount you ultimately receive.
Running several scenarios can give you a broader perspective than relying on one expected rate.
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Compound Interest Calculator FAQs
Find answers to common questions about compound interest, contributions, compounding frequency and long-term growth.
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