See exactly how your savings and investments grow over time. Enter your starting amount, interest rate, monthly contributions, and time horizon — get your final balance plus a year-by-year breakdown.
Your numbers
$0.00
Final balance
$0.00
Total contributions (incl. principal)
$0.00
Total interest earned
Growth over time
Your money (principal + contributions)Interest earned
Year
Start balance
Contributions
Interest earned
End balance
Math note: interest is applied to the running balance and compounds at the frequency you select. Monthly contributions are added at the start of each month. Figures ignore taxes, inflation, and fees.
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Unlimited calculations, breakdowns, and charts. No limits, no trial.
How to use
1
Enter your starting amount
Type your initial principal — for example $10,000 in savings or an investment account.
2
Set the rate, contribution, and time
Add your expected annual interest rate, how much you will add each month, and how many years the money will grow.
3
Pick a compounding frequency
Choose monthly, quarterly, or yearly compounding — more frequent compounding grows your money slightly faster.
4
Review your growth
Read your final balance, total interest, the growth chart, and the year-by-year table. Copy the summary to share or save.
Features
Year-by-year breakdown
See start balance, contributions, interest earned, and end balance for every single year.
Visual growth chart
Stacked bars show how much of your balance is your own money versus interest earned.
Flexible compounding
Compare monthly, quarterly, and yearly compounding to see how frequency affects returns.
Monthly contributions
Model real savings habits by adding a fixed contribution every month.
Clean USD formatting
Every figure is formatted as US dollars with two decimals for easy reading.
Private by design
All math happens on your device. Nothing you type ever leaves your browser.
Frequently asked questions
How does compound interest work?
Compound interest means you earn interest not only on your original money but also on the interest already added. Each compounding period, interest is calculated on the full current balance — so growth accelerates over time instead of staying flat.
Which compounding frequency should I choose?
Pick the one that matches your account. Most US savings accounts and CDs compound daily or monthly; many investment projections use monthly. More frequent compounding gives slightly higher returns because interest starts earning its own interest sooner.
When are monthly contributions added?
Contributions are added at the start of each month in this calculator, so they earn interest for the full month. Real accounts vary, but the difference versus end-of-month contributions is small.
Does this include taxes, inflation, or fees?
No. The results are gross figures before taxes, inflation, and account fees. For long-term planning, remember that real purchasing power grows more slowly than the nominal balance shown here.
What is the difference between interest rate and APY?
The interest rate you enter is the nominal annual rate. APY (annual percentage yield) reflects the effective rate after compounding. Monthly compounding at a 7% nominal rate equals about 7.23% APY.
Is my financial data sent anywhere?
No. This calculator runs entirely in your browser with JavaScript. No data is uploaded, stored, or shared — you can even disconnect from the internet after the page loads and it still works.
