This compound interest calculator projects how a balance can grow when interest is added to principal over time.
Finance
Compound Interest Calculator
Project future value with monthly compounding and contributions.
Calculator
About this calculator
Formula notes
A common model is A = P(1 + r/n)^(nt), where P is principal, r is annual rate, n is compounding frequency, and t is time in years.
Worked examples
- Example: 10000 initial plus 500 per month at 5% for 10 years grows to about 94111, with 70000 contributed and about 24111 earned as interest.
- An initial $5,000 earning 6% annually with $200 added monthly grows to about $19,160 after 5 years with monthly compounding, depending on contribution timing.
How to use it
- Enter the starting principal and annual rate.
- Choose the compounding frequency and time horizon.
- Review the future value and growth.
Frequently asked questions
Does this include regular contributions?
Only if the tool inputs support deposits. Pure compound growth uses the starting balance alone.
Does a higher compounding frequency always matter a lot?
Not always. At modest rates the difference can be small, but it grows with rate, time, and balance. Fees may outweigh it.
Limits and interpretation
- The entered return is assumed constant and does not represent market volatility, sequence risk, taxes, fees, or inflation.
- Contribution timing and compounding frequency affect the result; match them to the actual account rules.