Set it up in Slack or give it a try below:

/tz
↵  
  • Chicago, US: 10:34 am CST, Wed Nov 20th
  • Chicago is 1 hour behind you
  • Los Angeles, US: 8:34 am PST, Wed Nov 20th
  • Los Angeles is 3 hours behind you
  • Paris, FR: 5:34 pm CET, Wed Nov 20th
  • Paris is 6 hours ahead of you
  • Mumbai, IN: 10:04 pm IST, Wed Nov 20th
  • Mumbai is 10.5 hours ahead of you
  • Chicago is 2 hours ahead of Los Angeles
  • Chicago is 7 hours behind Paris
  • Chicago is 11.5 hours behind Mumbai

Examples: