Converting unix time into date-time via excel

Question

Trying to convert 1504865618099.00 Unix time into a readable date time. I tried this:

=(UNIX + (\"1/1/1970\"-\"1/1/1900\"+1)*86400) / 86400

Answer 1

If you have ########, it can help you:

=((A1/1000+1*3600)/86400+25569)

+1*3600 is GTM+1