GMT vs World Time

Both show a second time zone. They do it very differently.

GMT

• Independent 24-hour hand.
• Best for tracking one other zone (home or office).
• Adjustable in 1-hour jumps on "true GMT" calibres (Rolex GMT-Master II, Grand Seiko SBGE).

World Time

• Rotating disc shows all 24 zones at once.
• Best for travellers who visit many zones a year.
• Iconic versions: Patek 5230, Frédérique Constant Worldtimer.

If you cross more than three time zones a quarter, world time. Otherwise, a GMT will serve you better and read cleaner on the wrist.