Compound Interest Calculator
Calculate compound growth with monthly deposits or convert equivalent compounding rates.
Convert nominal interest rates between compounding frequencies without changing effective annual yield.
Result
How to use this calculator
Convert nominal interest rates between compounding frequencies without changing effective annual yield. Enter amounts in the units shown, select the applicable options, and click Calculate. Use Reset to restore the starting values.
Calculation formula
Effective yield = (1 + r/m)^m − 1; equivalent nominal rate = n × ((1 + yield)^(1/n) − 1).
Assumptions and accuracy
Review timing, rates, fees and result notes when comparing scenarios. Future returns and rates are assumptions rather than guaranteed outcomes. Monetary display follows the currency’s precision; intermediate calculations retain additional digits.
Choose what to calculate
Compound interest calculator with monthly contributions
Project the ending balance, total deposits and net earnings. This compound interest calculator with monthly deposits also supports annual contributions and beginning- or end-of-period timing.
Related searches: Compound interest calculator with inflation
Open this calculationCompound interest calculator daily
Project the ending balance, total deposits and net earnings. This compound interest calculator with monthly deposits also supports annual contributions and beginning- or end-of-period timing.
Open this calculationCompound interest calculator monthly
Project the ending balance, total deposits and net earnings. This compound interest calculator with monthly deposits also supports annual contributions and beginning- or end-of-period timing.
Open this calculationUnderstanding this calculation
Use the compound interest calculator with monthly contributions to project a savings balance, total contributions and net earnings. The separate Equivalent Interest Rate mode preserves effective yield when converting quoted rates.
Worked examples
Convert 5% nominal monthly compounding to an annual rate
Input interest rate 5%; input compounding Monthly; output compounding Annually.
- Monthly periodic rate = 0.05 ÷ 12.
- Effective annual yield = (1 + 0.05/12)^12 − 1.
The equivalent annually compounded rate is approximately 5.1162%.
Try these inputsCompound growth with monthly contributions
Start with 1,000 USD; deposit 100 at each month end for one year; 5% nominal annual rate compounded monthly; no tax or inflation adjustment.
- Monthly rate is 0.05 / 12.
- Ending balance = 1,000 × (1+0.05/12)^12 + 100 × ((1+0.05/12)^12 − 1)/(0.05/12).
Ending balance is approximately 2,279.05 USD; total contributions are 2,200 USD.
Try these inputsCommon questions
Where can I calculate compound growth with deposits?
Use Compound Growth on this page for starting money, monthly or annual contributions and a time horizon. Contribution timing controls whether deposits earn during their first period.
Does changing the frequency create extra return here?
In Equivalent Interest Rate mode, the quoted rate changes to preserve yield. In Compound Growth mode, changing compounding while holding the nominal rate fixed can change growth. These are different questions.
Scope and assumptions
Growth uses a constant nominal annual rate and its selected compounding equivalent; monthly and annual contributions are distinct cash streams. Tax and inflation adjustments are simplified. The conversion mode instead changes the nominal rate to preserve effective yield. Neither mode guarantees returns.
Sources
Calculation notes checked . Examples are mathematical checks under the stated assumptions.
Calculation methods and formulas
Equivalent Interest Rate
Convert nominal interest rates between compounding frequencies without changing effective annual yield.
Effective yield = (1 + r/m)^m − 1; equivalent nominal rate = n × ((1 + yield)^(1/n) − 1).
Compound Growth
Project the balance, contributions, and earnings over time.
Balance grows at the equivalent periodic rate, with contributions added at the selected timing.
See our calculation methodology and review status for data versions, rounding and validation limitations.