Compound Interest Calculator
Savings growth projection
Enter balance, contributions, and growth
Result
Calculation summary
Enter values to see the result
Growth preview
Projected balance by year
- Ending balance
- $100,133.64
- Total contributions
- $70,000.00
- Estimated growth
- $30,133.64
How to use this calculator
- 1Enter the starting balance and recurring monthly or annual contribution.
- 2Choose the annual rate, time, compounding frequency, and contribution timing.
- 3Optionally enter inflation to compare nominal growth with estimated purchasing power.
Formula
Future value = principal growth + compounded recurring contributions
The nominal annual rate is converted using the selected compounding frequency, and contributions are applied at the chosen beginning or end of each period.
Calculation steps
- Convert the nominal annual rate into the selected periodic compounding rate.
- Apply recurring contributions at the beginning or end of eligible months.
- Compound the balance through the selected number of months.
- Separate total contributions from estimated interest or investment growth.
- Discount the ending balance by optional inflation to estimate real value.
Worked example
An initial 10,000 with 500 added monthly for 10 years at a nominal 6% compounded monthly grows to an estimated balance of about 100,000.
Assumptions
- The entered return and inflation rates remain constant for the full projection.
- Contributions are made consistently at the selected timing.
- Taxes, fees, volatility, losses between periods, and provider rules are excluded.
- Changing currency changes formatting only and does not perform exchange conversion.
Sources
Frequently asked questions
What does compounding frequency change?
It changes how often the nominal annual rate is applied. More frequent compounding can produce a different effective annual rate.
What is contribution timing?
Beginning contributions earn growth during their contribution period; end contributions begin earning afterward.
Is the projected return guaranteed?
No. It is a mathematical projection using a constant entered rate, not an investment forecast or guarantee.
What does inflation-adjusted value mean?
It discounts the final nominal balance by the entered inflation rate to estimate future purchasing power in today’s terms.