 The Museum of HP Calculators

HP Forum Archive 20

 Problem with Interest entryMessage #1 Posted by Don Griffith on 15 June 2011, 11:33 a.m. 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.``` Nowhere can I see that the 12C automatically converts the % decimal. Am I missing something? Thanks for your answers

 Re: Problem with Interest entryMessage #2 Posted by gene wright on 15 June 2011, 4:46 p.m.,in response to message #1 by Don Griffith 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.

 Re: Problem with Interest entryMessage #3 Posted by Allen on 15 June 2011, 7:52 p.m.,in response to message #1 by Don Griffith 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.

 Re: Problem with Interest entryMessage #4 Posted by gene wright on 16 June 2011, 8:24 a.m.,in response to message #3 by Allen True, but even those where you specify the interest rate take interest input as 10 and not 0.10. :-) Go back to the main exhibit hall