Need context? Read our investing and compounding guide for assumptions and strategy.
Read the guide| Year | Contributions | Interest | Balance |
|---|
Compound interest guide
Use this calculator to estimate how savings or investments grow with regular contributions. The projection assumes a constant rate and reinvested gains.
Time is powerful
Longer timelines allow interest to compound on itself, creating larger gains later.
Rate assumptions
Small differences in assumed return can lead to large differences in outcomes.
Consistent contributions
Adding money regularly often matters more than chasing short-term performance.
How compounding works
- Interest is earned on both your original principal and previous interest.
- More frequent compounding produces slightly higher totals.
- Regular contributions increase the base that earns interest.
Real-world adjustments
- Taxes, fees, and inflation can reduce real returns.
- Markets fluctuate, so actual returns may be uneven year to year.
- Revisit assumptions as your risk tolerance changes.
How to use the results
- Compare different contribution levels and time horizons.
- Use conservative rates for planning and upside cases for sensitivity.
- Set milestones to track progress over time.
Compound interest calculator FAQ
Is the interest rate guaranteed?
No. The rate you enter is an assumption. Actual investment returns can vary each year and may be higher or lower than expected.
What compounding frequency should I use?
Use the frequency that matches your account terms. Many savings products compound monthly or daily, while some investments effectively compound as returns are reinvested.
Does this calculator include taxes or inflation?
No. The results are nominal and do not account for taxes, fees, or inflation.
How often should I contribute?
Consistent contributions are typically more important than frequency. Choose a schedule you can maintain, such as monthly or per paycheck.