Doubt about IRR

[TMD_]

Hello everyone,

I have a litle problem at work and i have difficulty solving it.

Here it goes:

I am trying to use the IRR function (just like excel) to calculate what we call TAEG / interest rate.

The problem i using the IRR function in a pratical way.

Basically i have (for example) a stable monthly payout of 47.22 € and i want to use the IRR to calculate what kind of rate i will have after 72 months. The initial outlay is 2462.5 for example.

In sas i tried using the formula irr(12, -2462.5, 47.22, 47.22, 47.22, 47.22, 47.22, 47.22) and it returns -99€. 

What i assume is that i have to put 1 as the beginning value and put the monthly payout 72 times...but it is just not pratical, even more since i have more than one example. 

Isn't there a simpler way when you have a stable monthly payout? Should i try to do a cycle?

Thanks for the help guys.

[Kurt_Bremser]

If you want the yearly interest rate, do this:

data test;
init = 2462.5;
yearly = 47.22 * 12;
rate_percent = irr(1, -init, yearly, yearly, yearly, yearly, yearly, yearly);
run;

[TMD_]

Does not work completly

I am using this in excel : =+(1+IRR(G54:G174))^12-1 

Which means that in G54 to G174 there is in G54 the -2462.5 € and from G55 to G126 there is only the value 48.71€.

The final result is 13.18% .

In sas using the formula you gave me it hits 8.4560170962. 

What am i doing wrong? 

[TMD_]

Basically if i do irr(12, -initialpayout, monthly pay (n) to (n+1))  it works.

But i have 72 months, it is not very pratical....any work around?