Thank you JulieS, U R my

But (there is always some kind of but)!
Between jan 1st and feb 1st result is 31.88 days.
That .88 is from feb 1st till 17:00 (i can see that on Gant)
Is there solution to make some kind of 24/7 calendar with working times 0-24?
In that case Gant will be from jan 1st at 0:00 till feb 1st 0:00.

And another 100... thnx for your time and efort.