Compound Interest Calculator
Project your investment’s future value with monthly contributions and different compounding schedules.
Inputs
Effective monthly rate: 0.5000%
Results
Future value
$100,134
Total contributions
$60,000
Total interest
$30,134
Effective annual rate
6.17%
Projected balance
See how your balance grows at the end of each year.
Email my calculations
Receive a printable breakdown (PDF) to revisit your calculations later.
Year-by-year breakdown
| Year | Start balance | Contributions | Interest | End balance |
|---|---|---|---|---|
| 1 | $10,000 | $6,000 | $785 | $16,785 |
| 2 | $16,785 | $6,000 | $1,203 | $23,988 |
| 3 | $23,988 | $6,000 | $1,647 | $31,635 |
| 4 | $31,635 | $6,000 | $2,119 | $39,754 |
| 5 | $39,754 | $6,000 | $2,620 | $48,374 |
| 6 | $48,374 | $6,000 | $3,151 | $57,525 |
| 7 | $57,525 | $6,000 | $3,716 | $67,241 |
| 8 | $67,241 | $6,000 | $4,315 | $77,556 |
| 9 | $77,556 | $6,000 | $4,951 | $88,507 |
| 10 | $88,507 | $6,000 | $5,627 | $100,134 |
source: calestimator.com/compound-interest-calculator
How to use the Compound Interest Calculator
Project how contributions, rates of return, and compounding frequency work together so you can set realistic savings goals.
- Enter the starting balance, planned contributions, and how often you contribute.
- Choose an annual return assumption that matches your investment mix.
- Set the compounding period (monthly, quarterly, annually) to mirror your account rules.
- Review future value, interest earned, and contribution totals to keep your plan on track.
Compound Interest Calculator key terms
Knowing how each field influences the results keeps the math grounded in reality.
Compounding frequency
How often interest is added to the balance. More frequent compounding accelerates growth.
Future value
The projected balance at the end of the time horizon, including contributions and earnings.
Real return
Growth after accounting for inflation. Use this to align projections with purchasing power.
Compound Interest Calculator planning ideas
Try running a few “what if” scenarios to translate the numbers into real-world decisions.
Catch-up savings
Increase contributions in later years to see how additional cash accelerates retirement milestones.
Market volatility stress test
Compare optimistic and conservative return assumptions so you know how resilient your plan is.
Lump-sum windfall
Add a one-time deposit to estimate the long-term impact of bonuses, inheritances, or asset sales.
Frequently asked questions
What return assumption should I use?
Base it on your asset allocation. Broad stock indexes historically earn around 7% after inflation, while bond-heavy portfolios may earn less. Consider running multiple scenarios.
Does the tool include taxes or fees?
No. Add a conservative buffer to your return assumption if you expect advisor fees or taxes to reduce performance.