What is the difference between a flyer and a caller GMT?

On a flyer, or 'true' GMT, the crown jumps the main hour hand in one-hour steps, so you change local time when you travel without stopping the watch. On a caller or office GMT, the crown jumps the 24-hour GMT hand instead, which suits keeping track of a colleague's time zone while you stay put.

How do I read the GMT hand?

Read it against the 24-hour scale on the bezel or dial. It goes round once a day, so 18 means 6 p.m. in that time zone.

Can I track three time zones?

Yes, with a rotating 24-hour bezel: turn the bezel by the hour difference of the third zone and read the GMT hand against it.

How to Use a GMT Watch: Set and Read Two or Three Time Zones

How to use a GMT watch

A GMT watch has an extra hour hand that goes round once a day. Set the normal hands to where you are and the GMT hand to home, and you can read both at a glance.

Setting it

Unscrew the crown if it screws down.
Pull it to the time position and set the hour, minute and GMT hands to your home time. The GMT hand reads against the 24-hour scale, so 3 p.m. is 15.
Push the crown to the middle position. On a flyer GMT, this jumps the main hour hand an hour at a time: move it to local time, and the date follows forwards and backwards.
On a caller GMT, the middle position moves the GMT hand instead: set it to the second time zone you want to follow.
Push the crown in and screw it down.

Flyer or caller?

Most expensive GMTs, such as the Rolex GMT-Master II and Tudor Black Bay GMT, are flyers: built for travellers who change local time often. Many affordable GMTs using the Seiko NH34 or similar movements are callers: easier to make, and fine if you mostly stay home and track one other zone. Neither is better; check which one you're buying.

A third time zone with the bezel

If the 24-hour scale is on a rotating bezel, turn it by the hour difference to a third zone. The GMT hand now reads the third zone on the bezel while the main hands show local time, and the GMT hand against the 24-hour track on the dial, if there is one, still shows home.

Affordable GMT watches

The least expensive current GMT watches in our catalog:

Timex Q Timex GMT 38mm TW2V38000, $269
Dan Henry 1963 Pilot GMT 'Pepsi' DH63-K11, $390
Seiko 5 Sports Field GMT SSK023, $450
Orient Kamasu GMT RA-BC0001B30B, $495
Seiko 5 Sports SKX Sports Style GMT SSK003, $495

See all GMT watches, or how a GMT compares with a world timer.

Questions

What is the difference between a flyer and a caller GMT?: On a flyer, or 'true' GMT, the crown jumps the main hour hand in one-hour steps, so you change local time when you travel without stopping the watch. On a caller or office GMT, the crown jumps the 24-hour GMT hand instead, which suits keeping track of a colleague's time zone while you stay put.
How do I read the GMT hand?: Read it against the 24-hour scale on the bezel or dial. It goes round once a day, so 18 means 6 p.m. in that time zone.
Can I track three time zones?: Yes, with a rotating 24-hour bezel: turn the bezel by the hour difference of the third zone and read the GMT hand against it.