what does the 1 stand for in a 5/1 arm?

I am about to refi on a HML–my guy is saying 5/1 ARM would be good way to go—is it worth doing the intersest only? I am thinking of getting some cash out. So this the scenario—7.5 interest only----99K. If i want cash —he says it will be around 8%-- for the 1st and—then closer to 12% for 24K HELOC. Any thoughts?


5/1 ARM

The first number (5) refers to the time period the rate is fixed
The second number (1) refers to how often the interest rate will adjust after the fixed period ends. One meaning (1) year.

So simple—thanks!