Formula for Time to Seconds Isn't Calculating Correctly

I’m doing a simple spreadsheet to show backup speeds, times, bytes etc. My formula for converting time in hours:minutes:seconds is only working in the first field then when I drag the formula for the other dates it displays negative numbers that grow.

First image shows formulas, second image shows results.

What am I doing wrong?

Thank you for your time.

It might be that the start and end times were originally entered as dates. Dates and Times are treated as numbers where the whole number represents a day and the fraction is the time. When you use the HH:MM:SS display format you no longer see the day but it would still be used in the calculation.

You might see this by setting a cell equal to each of the times using a number format.

Thank you, that’s something else I’ll need to remember.

press the ctrl-key meanwhile youre pulling down the Starttime in Column B

That did it, thank you. I would never have thought to do that.