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Compound Interest Calculator
See how your money can grow over time with the power of compounding.
Your Investment Summary
This calculator is for educational purposes only and does not constitute financial advice.
Year-by-Year Breakdown
| Year | Contributions (Year) | Interest (Year) | Total Contributions | Total Interest | Balance |
|---|
How Compound Interest Works
Compound interest is interest calculated on both the money you originally invested and the interest that money has already earned. Unlike simple interest, which only grows the original amount, compounding lets your earnings generate their own earnings — which is why the growth curve gets steeper the longer you stay invested.
The formula behind this calculator combines three moving parts: your starting balance, any regular contributions you add along the way, and how often interest is applied (daily, monthly, quarterly, or annually). More frequent compounding — and consistent contributions — both accelerate growth over time.
Start Early
Time in the market matters more than timing the market. An extra 5–10 years of compounding can outweigh a much larger starting deposit invested later.
Stay Consistent
Regular monthly contributions, even small ones, compound alongside your initial investment and often make up a large share of the final balance.
Mind the Frequency
Daily or monthly compounding will always outperform annual compounding at the same nominal rate — the difference grows with time.
Frequently Asked Questions
What is compound interest?
Compound interest is interest earned on both your original investment and on the interest that investment has already accumulated, causing your balance to grow at an accelerating rate over time.
How accurate is this calculator?
The calculator uses standard compound interest formulas and assumes a constant interest rate and consistent contributions. Real investments fluctuate, so treat the results as an educational estimate rather than a guarantee.
Does compounding frequency really matter?
Yes. More frequent compounding (daily or monthly versus annually) produces a slightly higher effective return on the same nominal interest rate, and the gap widens the longer money stays invested.
Should monthly contributions be included?
Including regular contributions gives a far more realistic picture for most savers, since ongoing deposits often account for a larger share of the final balance than the initial lump sum.
Is this financial advice?
No. This tool is provided for general education only. Speak with a licensed financial advisor before making investment decisions.
