Hi Mel,

There is nothing wrong with your formula, it works just fine as is.
It sounds like you are getting a very large number from it.
Excel only handles numbers up to 15 digits. After that
it just adds zeroes, that's what the E+12 is all about.
Whatever the number is move the decimal point
12 places to the right substituting zeroes after you
run out of numbers.

HTH
Martin