Compound Interest Calculator
Compound Interest Calculator
See how your money grows with compound interest. Enter an initial investment, monthly contributions, interest rate, and time period to project your future balance — with a year-by-year growth table.
Year-by-year growth
| Year | Invested | Balance |
|---|
How to use the compound interest calculator
- Enter your initial investment and optional monthly contribution.
- Set the expected annual interest rate and the number of years.
- Choose how often interest compounds — monthly, quarterly, or yearly.
- See your projected balance, total invested, and interest earned, plus yearly growth.
Why compounding matters
Compound interest earns returns on your returns. At 8% with monthly contributions of 5,000 on top of a 100,000 start, 10 years grows to roughly 1.13 million — of which about 430,000 is pure growth. The longer the time horizon, the more compounding dominates.
Tips
- Start early: time matters more than the rate for long horizons.
- Stay consistent: regular contributions beat lump sums for most savers.
- Mind inflation: this calculator shows nominal growth; subtract inflation for real purchasing power.
- Taxes and fees are not included — actual returns will be lower after both.
Frequently asked questions
What is a realistic interest rate? It depends on the investment — savings accounts pay little, diversified market portfolios have historically averaged higher but with volatility.
Monthly vs yearly compounding? More frequent compounding grows slightly faster, but the difference is small compared to rate and time.
Is this financial advice? No — it is a projection tool. Talk to a qualified advisor for personal decisions.