Compound Interest Calculator — compounding + contributions.
Compound Interest Calculator
Project how money grows over time with compounding and periodic contributions.
Investment inputs
Projection snapshot
How compound growth works
Compound interest means earnings generate additional earnings over time. That effect is amplified when you add regular contributions, because each deposit has more time to compound and work in your favor.
This calculator uses a monthly contribution model and applies the selected compounding frequency to the account balance as the years pass. The result illustrates the power of consistent investing and reinvestment.
In real life, actual investment performance can vary due to market volatility, taxes, fees, contribution timing, and changes in annual return. This is a planning estimate rather than a guarantee of future results.
- Compounding increases returns as time grows.
- Monthly contributions accelerate growth.
- Higher rates and longer time horizons materially increase the outcome.
- Actual performance can vary with market conditions and fees.
Frequently asked questions
What is compound interest?
It is interest earned on both the original balance and prior interest, causing growth to accelerate over time.
How do contributions affect the result?
Regular deposits add to the account balance and give the investment more principal to compound, which can significantly raise the future value.
Does compounding frequency matter?
Yes. More frequent compounding means interest is added to the balance more often, which can slightly increase returns over time.
Is this a guarantee of investment returns?
No. This is a planning tool only and does not promise market performance, tax treatment, or investment outcomes.
Does it include inflation or taxes?
No. This estimate focuses on nominal growth and does not adjust for inflation, taxes, fees, or investment volatility.
Why use monthly contributions?
Monthly contributions are a common saving pattern and allow the model to reflect how regular deposits can add up over time.