What is compound interest?
Compound interest is interest calculated on the principal plus interest already added in previous periods.
Finance Calculator
Compound Interest Calculator
Use this compound interest calculator to estimate future value from a starting amount, annual interest rate, time period, and compounding frequency. Results are mathematical illustrations based on the values you enter.
Compound Interest Calculator
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Compound Interest Calculator
Use this compound interest calculator to estimate future value from a starting amount, annual interest rate, time period, and compounding frequency. Results are mathematical illustrations based on the values you enter.
This calculator is for informational and mathematical illustration only. It does not provide financial, investment, tax, or legal advice. Results depend on the values you enter and do not predict actual returns. Taxes, inflation, fees, changing rates, liquidity, and risk are not included unless you model them separately.
What Is Compound Interest?
Compound interest is interest calculated on both the original principal and the interest that has already been added to the balance. Over time, this creates a growth pattern where each period can start from a larger base than the previous one.
Compound Interest Formula
The standard compound interest formula is A = P(1 + r/n)^(nt). In this formula, A is the future value, P is the principal, r is the annual rate as a decimal, n is the number of compounding periods per year, and t is time in years.
How Compounding Frequency Changes the Result
Compounding frequency controls how often interest is added back to the balance. With the same annual rate and time period, monthly compounding usually produces a different future value than yearly compounding because the balance is updated more often.
Simple Interest vs Compound Interest
Simple interest is calculated only on the starting principal. Compound interest recalculates from the growing balance after each compounding period. The difference is usually small over short periods and can become more visible as the time period gets longer.
Compound Interest Example
If the principal is 1,000, the annual rate is 10%, the time period is 2 years, and compounding is yearly, the future value is 1,210. The interest earned in that simplified example is 210.
What This Calculator Does Not Include
The calculator does not automatically include taxes, inflation, account fees, commissions, variable interest rates, liquidity limits, or risk. If any of those factors matter for your real-world situation, treat this result as a math checkpoint and model those items separately.
Frequently Asked Questions
The FAQ below explains the main formula terms, how frequency affects the output, and why real-world results can differ from a simple compound-interest calculation.
Frequently Asked Questions
What is the compound interest formula?
The common formula is A = P(1 + r/n)^(nt), where A is future value, P is principal, r is the annual rate, n is compounds per year, and t is time in years.
What is the difference between simple and compound interest?
Simple interest applies only to the starting principal. Compound interest adds each period's interest to the balance so later interest is calculated from a larger amount.
How does compounding frequency affect the result?
More frequent compounding updates the balance more often. With the same annual rate and time period, monthly and yearly compounding can produce different future values.
Does the result include taxes, inflation, or fees?
No. The result follows only the values you enter. Taxes, inflation, fees, commissions, and other costs are not included unless you model them separately.
Can I use this calculator for savings or investments?
You can use it as a mathematical scenario tool for savings or investment-like growth inputs, but it does not evaluate products, risks, taxes, or suitability.
Is the compound interest result professional guidance?
No. The result is an informational math example based on your inputs and should not be treated as financial, investment, tax, or legal advice.
What is future value?
Future value is the estimated ending balance after applying the entered rate, time period, and compounding frequency.
What does principal mean?
Principal is the starting amount used in the calculation before any interest is added.
Why can actual returns be different?
Actual outcomes can differ because rates change, taxes and fees may apply, inflation affects purchasing power, and real-world products carry risks and liquidity limits.