What is a GMT watch? How to use one (with a live demo)

A GMT watch has an extra hand that turns once every 24 hours and points to a 24-hour bezel or scale, so it can show a second time zone alongside local time. With a rotating bezel it can track a third. GMT stands for Greenwich Mean Time; the most famous GMT watch is the Rolex GMT-Master, created with Pan Am for pilots in the 1950s.

GMT means	Greenwich Mean Time
Extra hand turns	Once every 24 hours
Time zones shown	2, or 3 with the bezel
Early 24-hour pilot's watch	Glycine Airman, 1953
Most famous	Rolex GMT-Master ("Pepsi"), with Pan Am
Affordable entry	Seiko 5 Sports GMT, about $500

Live GMT watch demo

The white hands show your local time. The red 24-hour hand shows a second time zone; read it against the red-and-blue 24-hour bezel, red for daytime and blue for night. Pick a zone:

Second time zone

How a GMT watch works

A GMT watch has a fourth hand that goes around the dial once every 24 hours instead of twice. It points to a 24-hour scale on the bezel or the dial, so there is never any AM/PM confusion: if the GMT hand points at 23, it is 11 PM in that zone. GMT stands for Greenwich Mean Time, the old world time standard. UTC replaced it as the world standard in the 1960s and 1970s, but watchmakers kept the name.

"True" GMT vs "office" GMT

	Flyer or "true" GMT	Caller or "office" GMT
What you adjust	The local hour hand jumps in one-hour steps	The 24-hour GMT hand jumps on its own
Best for	Travelers: land, click the hour hand to local time, and home time stays on the GMT hand	People at home who call or work with another zone
Date	Usually follows the local hour hand forward and back	Must be set separately
Examples	Rolex GMT-Master II, Tudor Black Bay GMT, Grand Seiko, Longines Spirit Zulu Time	Many affordable GMTs with Swiss Sellita or Japanese movements

How to use a GMT watch, step by step

Set the GMT hand to home time, or to UTC if you are a pilot, using the 24-hour scale.
Set the hour and minute hands to local time. On a flyer GMT, just jump the hour hand when you change zones.
For a third zone, turn the bezel. With the bezel at its normal position (24 at the top), the GMT hand reads zone two. Rotate the bezel by the time difference, one hour per notch, and the same hand now reads zone three against the bezel. Example: if the GMT hand shows London at 14:00, turning the bezel 9 hours puts 23 under the hand, which is Tokyo time.

Not sure of the difference? Our time zone converter and world clock do the math.

History: pilots, Pan Am and the "Pepsi" bezel

Jet airliners in the 1950s crossed time zones faster than anyone before, and pilots needed to read home time and UTC at a glance. Glycine's Airman of 1953 had a 24-hour dial for exactly that. Then Pan Am worked with Rolex on the GMT-Master, reference 6542, released in the mid-1950s (sources say 1954 or 1955). Its red-and-blue bezel showed day and night hours, and its nickname, "Pepsi", stuck. The first GMT-Master II, the 16760 nicknamed "Fat Lady", followed in 1983.

Rolex GMT nicknames

Pepsi: red and blue bezel.
Coke: red and black.
Batman: black and blue, on an Oyster bracelet (2013). Batgirl: the same on a Jubilee (2019).
Root Beer: brown and gold.
Sprite, or "Destro": green and black with the crown on the left side (2022), Rolex's first left-handed production watch.

Best-known GMT watches and prices

Watch	Type	US price (approx.)
Rolex GMT-Master II (Pepsi, Batman, Sprite)	Flyer	$11,800 to $12,000 list; often well above on the secondary market
Tudor Black Bay GMT / Black Bay 58 GMT	Flyer	about $4,400 to $5,300
Grand Seiko GMT (e.g. SBGM221)	Flyer	about $4,900
Longines Spirit Zulu Time	Flyer	about $3,000 to $3,200
Christopher Ward C63 Sealander GMT	Caller	about €1,350 to €1,600
Seiko 5 Sports GMT (SSK001)	Caller-style	about $500

Prices are approximate 2024 to 2026 list or dealer prices and change often.

Questions people ask

What does GMT mean on a watch?

Greenwich Mean Time. On a watch it means a 24-hour hand for a second time zone. The world standard is now UTC, but the name stuck.

How do you read a GMT watch?

Read local time from the normal hands, and the second zone from where the 24-hour hand points on the 24-hour bezel or chapter ring. If it points at 18, it's 6 PM there.

What is a true GMT watch?

One where the local hour hand can be jumped in one-hour steps without stopping the watch, while the 24-hour hand stays on home time. It is ideal for travelers.

Can a GMT watch show three time zones?

Yes. Rotate the bezel by the hour difference and read the GMT hand against the bezel for a third zone, while the fixed inner scale (if there is one) still shows the second.

What is the Rolex Pepsi?

The nickname for the GMT-Master and GMT-Master II with a red and blue bezel, red for daytime hours and blue for night.

Sources

Last updated October 18, 2026. Prices are auction hammer-plus-premium results or published list prices as reported by the sources below; retail prices change, so check an authorized dealer before buying. Brand and model names belong to their owners and are used here only to identify the watches; onlineclock.app is not affiliated with any watch brand. Found an error? Tell us.