Compound Interest Calculator — See Your Money Grow Over Time
Calculate compound interest with regular contributions and see how your money grows with daily, monthly, or annual compounding. Free, instant results and charts.
By Konstantin Iakovlev · Updated April 2026 · Source: SEC
Future Value
$300,850.72
Total Contributions
$130,000.00
Total Interest Earned
$170,850.72
Summary
| Initial Deposit | $10,000.00 |
| Monthly Contribution | $500.00 |
| Interest Rate (monthly) | 7.00% |
| Total Contributions | $130,000.00 |
| Total Interest Earned | $170,850.72 |
| Future Value | $300,850.72 |
Growth Over Time
| Year 5 | $49,972.70 |
| Year 10 | $106,639.02 |
| Year 15 | $186,970.62 |
| Year 20 | $300,850.72 |
Use the Compound Interest Calculator — See Your Money Grow Over Time above to calculate your results. Enter your values and see instant results — all calculations run in your browser.
Disclaimer: This calculator is for informational purposes only and does not constitute tax, financial, or legal advice. Results are estimates based on the information you provide and current rates. Always consult a qualified tax professional or financial advisor for advice specific to your situation.
How It Works
Compound interest is what lets a modest balance grow into a meaningful one, and seeing it laid out year by year makes the effect tangible. Plug in your regular contributions and pick a compounding frequency — daily, monthly, or annually — to project where your savings are headed. With 2026 inflation running near 2.5%, knowing whether your returns are outpacing rising costs matters more than ever.
Behind the projection sits the standard formula A = P(1 + r/n)^(nt) + PMT * [((1 + r/n)^(nt) - 1) / (r/n)]. Here A is the future value, P the starting principal, r the annual interest rate, n the number of times interest compounds each year, t the number of years, and PMT each periodic contribution. Combining the growth of your principal with ongoing deposits gives a realistic picture of how the balance accumulates.
A few caveats keep the numbers honest. These figures are projections, and real returns shift with market swings and changing interest rates, so the output is a guide rather than a guarantee. The flip side is easy to overlook: small, steady contributions compound into surprisingly large sums when given enough years to work.
Example: Saving for a Down Payment on a House by 2036
- 1 Imagine you start with a principal of $10,000, contribute an additional $200 per month, and earn an average annual interest rate of 6% compounded monthly. You want to see how much you'll have in 10 years, by 2036.
- 2 Using the formula, with P=$10,000, PMT=$200, r=0.06, n=12, and t=10, the calculator meticulously computes each month's interest and contribution. The interest earned is added to the principal before the next period's calculation, demonstrating the compounding effect.
- 3 After 10 years, your initial $10,000 investment plus your $200 monthly contributions, earning 6% compounded monthly, would grow to approximately $44,796.85. This significant growth highlights the power of consistent saving and compounding.
- 4 This example shows that by consistently investing, even modest contributions can lead to substantial wealth accumulation over time. This $44,796.85 could be a significant portion of a down payment for a house in 2036, illustrating the long-term benefits of disciplined financial planning.
Source: SEC · Last updated: April 2026
Frequently Asked Questions
How does compound interest differ from simple interest?
How often should interest compound for the best return?
What is the Rule of 72?
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