Compound Interest Calculator
See how savings grow with regular contributions and compounding.
The projection is computed inside your own browser and nothing you enter is uploaded; the only value kept is your currency choice, stored on this device.
Two compound interest calculators can return answers thousands apart from the same handful of inputs, because they quietly disagree about what the rate means and when the money arrives. This one states its convention rather than hiding it. The rate you enter is a nominal annual rate, compounded daily, monthly, quarterly or yearly according to the setting you choose, and the rate applied to each period is that annual rate divided by the number of periods in a year.
More about Compound Interest Calculator
Contributions are made either monthly or yearly, at the start or the end of each period, and each contribution grows at the effective rate for its own period. A contribution timed at the start earns one extra period of interest, which is why the start and end settings do not agree. Along with the final balance, the tool reports how much you put in, how much of the balance is interest, and the effective annual rate, which is what your nominal rate is actually worth over a full year once the compounding frequency is taken into account.
The projection assumes the rate never moves and every contribution is made on time. It models no inflation, tax, fees, day-count conventions or partial periods, so the balance it shows is an estimate rather than financial advice.
- The rate is treated as a nominal annual rate, compounded daily, monthly, quarterly or yearly.
- Contributions can be monthly or yearly, timed at the start or the end of each period.
- The effective annual rate is reported next to the balance, so the compounding choice is visible.
- Final balance, total contributions and interest earned are kept separate rather than merged.
- Projections run from one to sixty years.
- The assumptions in force are printed under the results in plain words.
- Seven currencies are supported, and every figure has its own copy button.
How to use it
- 1Enter your starting amount, or zero if you are beginning from nothing.
- 2Enter the annual rate, then choose how often it compounds.
- 3Enter how much you add regularly, and whether that happens monthly or yearly.
- 4Choose whether each contribution lands at the start or the end of its period.
- 5Set the number of years, then read the final balance, the interest earned and the effective annual rate.
Questions
Why does another calculator give a different number?
Almost every difference comes down to the compounding frequency and the contribution timing, which many calculators never disclose. Match the compounding setting, the contribution frequency and the start or end timing, and the two answers should line up.
What is the effective annual rate?
It is what the nominal rate is actually worth over a full year once compounding is applied, calculated as (1 + r/n)^n − 1 for a nominal rate r compounded n times a year. A 5 percent nominal rate compounded monthly comes out slightly above 5 percent.
Does it account for inflation, tax or fees?
No. The balance is a nominal figure, so its real purchasing power will be lower, and any tax or platform fee has to be subtracted separately.
Can I rely on this projection for a real decision?
No. It projects one fixed rate forward for the whole period, which is not how real investments behave.
Can I model saving from nothing?
Yes, set the starting amount to zero and enter a regular contribution instead. At least one of the two has to be above zero, otherwise there is nothing to grow.