THIS WILL CALCULATE: If you know the loan amount and the periodic payments, this will calculate your return on investment.

EXAMPLE: You are willing to loan me $35,000 and I will pay you back in equal payments of $800 per month, for 5 years, what is your rate of return on this investment. (or in otherwords, what interest rate am I paying)

Please note:  The    key changes the 800 to a negative number.  With the HP12C all cash outlays should be entered in as a negative number.  The result of 1.10 is a monthly return on investment.  You must multiple by 12 to get your annual return of 13.20.