Select your home city and travel city to see the exact hour difference.
Then follow clear instructions to set a true GMT hand or a 24-hour rotating bezel.
Calculate Offset
How to Set a True GMT Hand
On a true GMT watch the 24-hour hand (often a coloured arrow hand) can be set independently or jumps in one-hour steps.
1. Set the normal hour and minute hands to your local (travel) time.
2. Set the GMT / 24-hour hand to your home time on the 24-hour scale.
3. Example: if home is London and it is 14:00 there, point the GMT hand at 14 on the 24-hour track.
Many modern “traveller” GMT watches let you jump the main hour hand in one-hour steps while the GMT hand and minutes stay fixed — ideal when you land in a new time zone.
How to Use a 24-Hour Rotating Bezel
This method works on any watch that has a 24-hour bezel (or a 12-hour bezel used carefully).
1. Set your watch to local time as usual.
2. Look at the current home time.
3. Rotate the bezel so that the home-time hour number sits under the hour hand (or under the 24-hour marker if present).
4. You can now read home time from the bezel while the hands show local time.
Always confirm whether your bezel is a 12-hour or 24-hour scale. A 12-hour bezel only works unambiguously for offsets up to 12 hours and needs AM/PM awareness.
GMT vs Dual-Time vs World-Time
True GMT – Independent 24-hour hand. Best for tracking one home time zone while travelling.
Dual-time – Usually two separate hour hands or a subdial for a second time zone.
World-time – City disc or multiple zone indications so you can read many time zones at once.
Important DST Note
Some cities observe Daylight Saving Time and shift by one hour for part of the year.
The offsets in this tool are standard (non-DST) values. Always double-check the current time difference on the day you travel if either city uses DST.
Frequently Asked Questions
Which time should the main hands show?Most travellers set the main hands to local time (the time where they currently are) and use the GMT hand or bezel for home time.
What is the advantage of a true GMT watch?You can read a second time zone at a glance without doing mental arithmetic, and many modern GMT watches allow easy one-hour jumping of the main hour hand when you change zones.
Can I use a normal dive bezel as a GMT bezel?A standard 60-minute dive bezel is not ideal for long-term dual-time tracking. A 24-hour bezel is far clearer for this purpose.
Why do some GMT watches have a 24-hour scale on the dial?The 24-hour track lets the GMT hand tell you unambiguously whether home time is day or night.
Do I need to adjust for DST manually?Yes. When either home or destination city starts or ends daylight saving, you must adjust the corresponding hand or bezel by one hour.