Want the full breakdown? Read Compound Interest: Complete Guide
Calculator #
Compound Interest Calculator
See how your money grows over time with compound interest
Your Investment Growth
Final Balance
$0
Total Contributions
$0
Interest Earned
$0
Contributions
Interest Earned
50%
50%
Growth Over Time
Input Fields #
| Field | What to Enter | Typical Values |
|---|---|---|
| Initial Investment | Starting lump sum | $0 - $50,000 |
| Monthly Contribution | Regular monthly amount | $100 - $2,000 |
| Time Period | Years to grow | 10 - 40 years |
| Annual Return | Expected yearly return | 5% - 10% |
| Compounding Frequency | How often interest compounds | Monthly (most common) |
tip
Use 7% for inflation-adjusted S&P 500 returns. Use 10% for nominal (before inflation).
Example #
| Input | Value |
|---|---|
| Initial | $5,000 |
| Monthly | $500 |
| Years | 25 |
| Return | 7% |
| Frequency | Monthly |
Result: $436,311 final balance — $155,000 contributed, $281,311 earned from compounding.
Quick Tips #
- Be conservative — Markets don’t return 7% every year
- Account for inflation — $436K in 25 years buys less than $436K today
- Factor in fees — 1% annual fees cost tens of thousands over decades
- Start now — Time matters more than timing
Related Calculators #
- FIRE Calculator — When can you retire?
- SWR Calculator — Safe withdrawal rates
- Emergency Fund Calculator — How much safety net?
Learn the math: Compound Interest: Complete Guide