Compound Interest Calculator
Calculate compound interest with multiple compounding frequencies and regular contributions.
Region: Global
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Quick Tip
Enter your initial investment.
About This Tool
Why use Compound Interest?
Compound interest means you earn interest on your interest. This calculator uses the formula A = P(1 + r/n)^(nt) for your starting balance and adds regular monthly contributions, so you can see how saving consistently grows over time.
For example, 10,000 invested at 7% compounded monthly, with 100 added every month for 10 years, grows to about 37,405. You deposit 22,000 in total, so around 15,405 comes from compound growth.
Key Benefits
Compounding frequency
Compare annual, quarterly, monthly and daily compounding and see the effective annual rate.
Regular contributions
Model monthly deposits, the way most people actually save or invest.
Growth multiple
See how many times your deposits have multiplied by the end of the period.
How to use Compound Interest
- 1
Enter your initial investment.
- 2
Add the annual interest rate and number of years.
- 3
Choose the compounding frequency: annually, semi-annually, quarterly, monthly or daily.
- 4
Add a monthly contribution and compare the final balance with the total deposited.
Best use cases
Use compound interest during loan comparison when you need a quick answer without installing software.
It fits savings planning workflows where speed and clear outputs matter.
The tool is also useful for budget review when you want results in one place.
Because the interface is focused, it helps reduce manual busywork across financial planning and numeric decision making.
Compound Interest FAQs
What is the compound interest formula?
A = P(1 + r/n)^(nt), where P is the principal, r the annual rate as a decimal, n the number of compounding periods per year and t the number of years.
Does compounding frequency make a big difference?
It helps, but less than the rate and time. At 7%, monthly compounding gives an effective annual rate of about 7.23% compared with 7% for annual compounding.
What is the Rule of 72?
Divide 72 by the annual rate to estimate how many years it takes money to double. At 8%, money doubles in roughly 9 years.
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