Calculate world time based on timezone

[MrVon]

have table world countries and GMT/UTC timezone for each.
Now i need to check what time is in all this countries when its 11am in USA (+8gmt)
how can i do so?

e.g. in russia is +3gmt

I tried 3+8+11 = 22pm in russia when in us is 11 but when country has minus zone it does not work for me someone know how to do it?

 

[GlennUK]

I thought that USA was -8gmt ( or thereabouts depending on what part of USA ). How is it that you have +8gmt?