Calculator

Final Value
Total Contributions
Total Interest Earned

Growth Over Time

Example

Initial Investment: $1,000
Monthly Contribution: $100
Interest Rate: 8% per year
Time: 10 years
Compounding: Monthly

Final Value ≈ $19,500

Formula Used

A = P(1 + r/n)nt + PMT × [((1 + r/n)nt − 1) / (r/n)]

What is compound interest?

Compound interest is interest earned on both your initial investment and on the interest that has already accumulated. Unlike simple interest, which only applies to the principal, compound interest accelerates your growth over time.

Why it matters

Growth accelerates over time because each compounding period adds interest to a larger and larger base. The longer you stay invested, the more dramatic the effect becomes — this is often called the "snowball effect" of compounding.

Key factors

FAQ

What is compounding frequency?

Compounding frequency is how often interest is calculated and added to your balance. Monthly compounding applies interest 12 times per year, while yearly compounding applies it once.

Why is time so important?

Because compounding is exponential. The longer your money compounds, the faster it grows. Doubling your time horizon often more than doubles your returns.

Is this realistic?

This calculator assumes a constant rate of return, which is a simplification. In reality, returns fluctuate year to year. It provides a useful estimate, not a guarantee.

Does this include inflation?

No. The values shown are nominal. To account for inflation, you can subtract an estimated inflation rate (e.g., 2–3%) from your expected return rate.