I am scheduling an online event that will be happening from 4-6pm Eastern Standard Time on a certain day. However, this online event will involve people from many different timezones, not just Eastern (I myself am in Central Time). And it's not just in America, it will involve people from Europe as well.
For the online invitations and other notifications (pretty much all digital) that I'm creating, I would like to make it as easy as possible for potential attendees to figure out what time the event will happen according to their local time. In other words, I'd prefer they not be forced to do the math or have to track down a converter website if they don't know how to figure out the start time in their local time zone.
Because of a wide range of time zones, I can't very well list them all. I had hoped there might be some way I can link to a website that would say "I detect that you're in X time zone, so the time 4-6pm EST is at Y time for you", but I can't find anything quite like that.
What is the best way to display the time of an international event in a way that is as easy for the user's experience as possible?
EDIT: I'm mostly talking about displaying a time in e-mail and online newsletters. I realize that on a website, I can just use some coding to detect the local time.