Inflation Calculator
See what an amount is worth over time at any inflation rate.
Compound Interest Calculator
Grow a balance with regular contributions and any compounding frequency.
| Year | Deposits to date | Interest to date | Balance |
|---|
Final balance
—
Starting balance—
Total contributed—
Total interest earned—
Interest as % of final
What made the balance
Your money
Interest
Quick Tool Overview
The Compound Interest Calculator grows a starting balance with an optional regular contribution at any compounding frequency, and separates in a year-by-year table what you paid in from what the interest earned — the number people consistently underestimate.
- What it does
- Projects a balance with compounding and regular contributions
- You give it
- A starting balance, a rate, a term and a contribution
- You get back
- The final balance with a year-by-year deposits versus interest split
- Best for
- Savings goals, pensions, ISAs and long-term planning
About the Compound Interest Calculator
Enter a starting balance, an annual rate, a term and an optional regular contribution to see how the balance grows. The year-by-year table separates what you paid in from what the interest earned, which is the number people underestimate.
Compounding rewards time far more than it rewards size. A contribution made in year one earns interest for the entire term, and interest on that interest for almost as long, while the same amount added near the end barely compounds at all. That asymmetry is why the total interest line curves upward rather than rising steadily, and why the calculator plots it separately from your deposits.
Key features of the Compound Interest Calculator
Deposits and interest separated
The table splits what you paid in from what the money earned, which is where the real story is.
Regular contributions supported
Model monthly or annual paying-in rather than a single lump sum sitting still.
Time beats size
A contribution made in year one earns interest for the entire term; the same amount added near the end barely compounds at all.
Any compounding frequency
Annual, monthly or daily, so the projection matches the product you actually hold.
The curve made visible
Total interest is plotted separately from deposits, which is why it curves upward rather than rising steadily.
How to use the Compound Interest Calculator
-
1
Set your starting balance
Enter what you are beginning with, or zero if you are starting from nothing.
-
2
Add regular contributions
Enter a monthly or annual amount you plan to keep adding.
-
3
Choose rate, term and frequency
Set the annual rate, how many years, and how often interest compounds.
-
4
Read the split
The table shows total deposits against total interest each year, so you can see when interest overtakes contributions.
Frequently asked questions
A equals P times (1 + r/n) to the power of n times t, where P is the principal, r is the annual rate, n is the number of compounding periods per year and t is the number of years. Regular contributions add a future value of annuity term on top.
A quick estimate of doubling time: divide 72 by the annual percentage rate. At 6 percent, money roughly doubles in twelve years. It is an approximation, but a good one for rates in the normal range.
Yes, from the moment each one is made. That is why starting early matters more than contributing more later — an early deposit has far longer to compound.
No, the result is a nominal figure. To see it in today's money, run the total through the inflation calculator, and remember that interest may be taxable depending on the account and jurisdiction.
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