Compound Interest Calculator

Initial Sum	$
Contribution Amount you add regularly. A negative number is the amount you plan to withdraw.	$
Term	years months
Interest Rate	% a year
Compound Frequency Times per year that interest is added to the balance.

More options: yearly contribution increase, tax on interest, inflation

Yearly Contribution Increase For example 3 if you will add 3% more every year.	%
Tax on Interest The percentage withheld from every interest payment.	%
Inflation Shows what the balance will be worth in today's money.	% a year

Target Amount
Find the contribution, term or rate you need to reach it.

APR to APY Calculator

Convert annual percentage rate to annual percentage yield.

APR % compounding is

APY to APR Calculator

Convert annual percentage yield to annual percentage rate.

APY % compounding is

How It Is Calculated

If you invest a sum [tex]P[/tex] at an annual rate [tex]r[/tex] compounded [tex]n[/tex] times a year, after [tex]t[/tex] years you will have

[tex]A = P\left(1 + \dfrac{r}{n}\right)^{nt}[/tex]

The rate [tex]r[/tex] is written as a decimal: [tex]5\% = 0.05[/tex]. With continuous compounding, interest is added at every moment and the formula becomes

[tex]A = Pe^{rt}[/tex]

For example, $1,000 at 5% a year for 10 years grows to [tex]1{,}000 \times 1.05^{10} \approx 1{,}628.89[/tex] dollars with annual compounding and to [tex]1{,}000 \times e^{0.05 \times 10} \approx 1{,}648.72[/tex] dollars with continuous compounding.

Contributions are made at the start or at the end of every month, quarter or year, as you choose. Between two compounding dates, every deposit earns simple interest for the time it has been in the account, and that interest is added to the balance on the next compounding date. If the term ends between two compounding dates, the interest earned until then is added too. Tax is withheld from every interest payment.

The balance in today's money is [tex]\dfrac{A}{(1+i)^t}[/tex], where [tex]i[/tex] is the yearly inflation rate.

Borrowing instead of saving? The loan calculator shows the monthly payment, the APR and the amortization schedule of a loan.