Models & Tools
Compound Interest Calculator
Explore how time, regular contributions, and compounding shape your investment balance.
Example inputs — replace with your own
Final balance
$170,619.05
Total contributions
$70,000.00
Includes your initial investment
Total interest
$100,619.05
How this works / Assumptions
Monthly rate = (1 + r/n)^(n/12) − 1 Balanceₘ = Balanceₘ₋₁ × (1 + monthly rate) + contribution
Returns are constant nominal annual rates, converted to an effective monthly rate using your compounding frequency. Contributions are added at month end. No taxes, fees, inflation, or market volatility are modeled. Years are whole years; daily compounding uses 365 periods per year.
Educational tool. Results are estimates based on your inputs and do not constitute financial advice.