Compound Interest Calculator
Calculate compound interest and investment growth over time.
Calculator InputsInstant Math
Results & Calculation SummaryVerified
Final Portfolio Balance
$1,628.89
Over 10 years with an initial principal of $1,000.00 and 5% interest compounded annually, your final balance will grow to $1,628.89, earning $628.89 in interest.
Initial Principal
$1,000.00
Total Deposits
$0.00
Interest Earned
$628.89
Yearly Growth Breakdown (First 5 Years)
| Year | Start | Interest | End Balance |
|---|---|---|---|
| Yr 1 | $1,000.00 | +$50.00 | $1,050.00 |
| Yr 2 | $1,050.00 | +$52.50 | $1,102.50 |
| Yr 3 | $1,102.50 | +$55.13 | $1,157.63 |
| Yr 4 | $1,157.63 | +$57.88 | $1,215.51 |
| Yr 5 | $1,215.51 | +$60.78 | $1,276.28 |
What is Compound Interest Calculator and How is it Calculated?
The CalcTower Compound Interest Calculator models how an initial investment or savings balance grows over time when interest compounds annually, monthly, quarterly, or daily, with optional recurring contributions.
A = 1000 * (1.05)^10 = $1,628.89 accumulated balance.
Model shows compounding growth on initial investment plus monthly additions.
Common Real-World Use Cases
Estimate how a retirement account balance could grow over decades given a steady contribution and an assumed annual return.
See how different compounding frequencies (monthly vs. daily vs. annually) change the final balance on the same rate.
Test how adding a fixed monthly deposit changes long-term growth compared to a lump sum left untouched.
How This Compares
Compound interest earns "interest on interest" because each period’s interest is added to the balance before the next period is calculated, so growth accelerates over time. Simple interest stays flat, calculated only on the original principal every period. If your loan or account explicitly states a flat, non-compounding rate, use the Simple Interest Calculator instead.
- 1Enter your Initial Principal amount.
- 2Specify the annual Interest Rate (%).
- 3Select Compounding Frequency (Annually, Semi-Annually, Quarterly, Monthly, or Daily).
- 4Set Investment Duration in years.
- 5Optionally add regular monthly or annual recurring contributions to see accelerated growth.
- •Compounding frequency significantly affects growth: more frequent compounding yields higher total returns over long horizons.
- •Adding even small monthly contributions dramatically increases long-term compound wealth.
- •Selecting the wrong compounding frequency for the actual account terms - a savings account that compounds monthly will not match a calculation run as annual compounding.
- •Entering a contribution amount without checking whether it should be monthly or annual - this changes the total contributed by up to 12x.
Results are estimates for informational and educational purposes and may differ from actual lender, bank, tax, or investment results.
Frequently Asked Questions
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