Variation and ranking

[itsjustmal]

I couldn't find a place to post this question so I was advised to create a new thread. I'm looking for a formula to calculate the variation from a standard time set e.g. 20:30 (mm:ss). I have around 23 different times in a column and I want to put a formula next to it to find the variation and then rank it based on the the finding e.g. rank out of 23 based on distance from a standard time. Any help would be appreciated!