hi yonkers, it's 8:30 pm on a Friday nite in NZ and I'm writing this on a crappy PDA lying in bed, so plz xcuse any typos or weird characters.

I'm glad you find my formula useful. don't know why it throws the #value error, though. if I were to do it, I'd create range names for the start and end time columns and use these in the formula. If you're using daily logs where the number of cells in a column changes all the time, look into dynamic range names that are defined with a combination of OFFSET(9) and COUNTA() to always include all populated cells in a column.

If you use range names you'll greatly reduce the risk of errors in the ranges used of the formula.

I'm keen to know how you're doing. This has been an intriguing challenge and I'd like to know if you managed to solve it to meet your requirements.

So, plz keep me updated and let me know if I can be of any more help. I'll be offline until Monday morning NZ time, though. My family needs me too.
cheers & have a gr8 weekend

teylyn