HP-12C Viewing the manual shows the following when entering interest in a financial calculation.

   Assume the problem has a interest rate of 13%

   Enter 13 on the numeric keys.

   Enter control key "g"

   Press the interest key which enters "13%" divided by 12

      or 1.08333 which is correct as far as it goes.

   I have always been taught that 13% is = .13 decimal.

Hi. The interest rates on the 12c (and most financial calculators) are expressed as you see in the manual, i.e., 13% is 13; 10% is 10.

When you divide by 12, you will see 10/12 or 0.8333, etc.

The calculator always does the "divide by 100" when it uses the interest rate.

Gene is right. To put it a different way, the 12C only uses periodic interest rate (no assumption is made about how many payments are made per annum)

In contrast, most of the other HP financial calculators accept only an annual interest rate, and a separate entry must be made for how many annual payments occur.

Most (like the 10B) will default to 12 P/Y when reset.

True, but even those where you specify the interest rate take interest input as 10 and not 0.10.

:-)