Working out my diff ratio

[shynsy]

I've got one of my drive shafts off at the mo on my 130S/5 while I was under the car I decided to check out my dif ratio. One out put shaft was locked so it didn't moved. I turned the input shaft and measured the number if turns it took to turn the output shaft one revolution.
I measured around 1.875 rotations of the input for one turn off the output. As one output was locked so it didn't move do I double the number. That would make the diff a 3.7:1.
Tim