Interest Rate Calculator

Compound / Simple Interest Calculator

Starting Amount (PV)?:
Annual Interest Rate?:
Number of Days? (#):
Start Date? (m/d/y):
End Date? (m/d/y):
Compounding Frequency?:
Days In Year?:

Interest Earned:
Future Value (FV):
Annual Percentage Yield (APY):
Daily Interest Rate?:
This free, online interest calculator (c) 2010 Pine Grove Software, LLC All rights reserved.

Enter an amount and a nominal annual interest rate.

Date Math: If you change either date, the number of days between the two dates will be calculated. If you enter a positive number of days, the end date will be updated. If you enter a negative number of days the start date will be updated.

The above means you can calculate interest for a specific number of days and not worry about what the dates are. If you need to know the interest for 31 days, then enter 31 for the number of days and don't worry about the dates.

Set the compounding and the rate basis. Click "Calc". The interest will be calculated for the exact number of days. Additionally, the future value is calculated (Initial amount plus the interest.) The annual percentage yield is used for comparing investments. It is the rate institutions must quote in the US for interest bearing accounts. The holder of such an account can use the APY to compare accounts.

Interest may be calculated based on a unit of time, say a month. In that case, a month's interest is always the same for the same interest rate and same principal balance regardless of the length of the month. Given $10,000 principal and an interest rate of 6.75% the interest will be the same for February as it will be March.

There is also exact day interest. Interest is calculated based on the exact number of days. This calculator calculates exact day interest and the future value.