Time difference as a percentage

[Fluffman]

Greetings ppls.

I need to calculate the difference between a start time/date and a finish time/date, and return the result as a percentage instead of a time value.

The end time would be equal to 100% and start time would be equal to 0%

The difference is usually always a maximum of 5 days only.

I've tried the simple formula of End time - Start time, but I don't know how to convert it to a percentage.

Thanks.

 

[mikerickson]

If you have Start Time in A1 and Stop Time in A2 and TimeOfNote in A3

=(A3-A1)/(A2-A1)

will return the percentage of the total duration that has passed at the TimeOfNote.