What is GMT time and how can you use this function on your watch?
Not every watch shows just one time – some can do much more. The GMT function allows you to track time in two, or even three time zones simultaneously, making it perfect for travelers, pilots, and people working internationally. Before you learn how it works and what the GMT time zone actually is, it's worth knowing its history – from London's Greenwich to modern watches with the most advanced mechanisms.
GMT – what does it mean? Discover the fascinating history of time from which the whole world counts
Although you don't think about where the time you see on your watch dial comes from on a daily basis, it's worth knowing that it all starts with GMT, or Greenwich Mean Time. This term refers to mean solar time on the prime meridian, which runs through the London district of Greenwich. It was this point on the map that became the baseline from which all other time zones began to be measured.
This is where the name GMT time zone came from, which for decades has been the reference point for the entire world – in shipping, aviation, and everyday life. In practice, if you hear that someone operates in GMT+2 time, it means their local time is two hours ahead of London. It's a simple system, but extremely important for synchronizing work, travel, and global communication.
It's worth knowing that GMT's history dates back to the 17th century, when the Royal Astronomical Observatory was established in Greenwich. It was there that it was determined that the meridian passing through this point would be considered "zero." Over time, the system was adopted by other countries, and in 1884, at an international conference, it was established as the official standard. Interestingly, France long opposed these arrangements, preferring its own Paris meridian – it wasn't until 1911 that it officially recognized Greenwich. Today, GMT serves mainly a historical function, as it was replaced in the 1960s by the more accurate UTC (Coordinated Universal Time), but for watch users and in everyday language, the concept of GMT is still alive. It was this concept that became an inspiration for watchmakers who began creating models that allow tracking more than one time zone.
Zeppelin Atlantic GMT 8442-3 is an elegant men's watch that values classics and functionality in a modern edition. With a navy blue dial, leather strap, and GMT complication, it's perfect both for travel and business meetings, emphasizing the style, class, and precision of German watchmaking craftsmanship.
How the GMT function works in a watch – discover how to read time in two (or even three) time zones simultaneously
The GMT function in a watch is something many consider one of the most practical mechanical complications. Its operation is simple but extremely useful. On the dial, you'll find an additional hand – often ending with a characteristic triangle-shaped arrow. This is the GMT hand, which makes a full rotation once every 24 hours, not twice like the standard hour hand. This makes it easy to distinguish whether it's day or night in the second time zone. Usually, the dial or ring (called the bezel) features a 24-hour scale that allows you to read the time in another part of the world. In practice, you can simultaneously track, for example, local time and time in the country you're from.
Some watches go a step further – they're equipped with a rotating bezel that allows reading even a third time zone. Simply turn the ring forward or backward by the appropriate number of hours, and you'll know what time it is in Tokyo or New York, for example. This solution is appreciated by both travelers and people who collaborate with partners from different parts of the world. With the GMT function, you don't have to calculate hours "in your head" or check time differences on your phone – you have everything on your wrist. Moreover, GMT time displayed this way is extremely readable and allows you to immediately orient yourself in time regardless of which part of the globe you're in.
Gerlach PZL P.50 Jastrząb GMT is a tribute to Polish aviation and technical precision, inspired by the legendary fighter from the 1930s. Equipped with an automatic movement with GMT function, it combines military character with elegance and solid craftsmanship, creating a watch ideal for history and aviation adventure enthusiasts.
True GMT or Caller GMT? Check which type of watch suits your lifestyle
Not every watch marked GMT works the same way, so it's worth knowing that there are two main types – True GMT (Flyer GMT) and Caller GMT (Office GMT). The difference between them is subtle, but significant for the user. In True GMT models, the main hour hand moves independently, allowing you to quickly adjust local time without interfering with the GMT hand, which remains set to home time. This solution was created with frequent travelers who cross different time zones in mind – it takes just a moment to adjust the watch to a new location.
On the other hand, Caller GMT works better if you don't physically change time zones but want to track time in another place – for example, when you work with international clients or have family in another country. In this type of mechanism, the GMT hand is adjusted independently, while local time remains unchanged. This makes it easy to set the appropriate time in, for example, New York, Tokyo, or Sydney, without needing to change the main clock. This is why watches of this type are often called "office" watches – ideal for people who constantly function between different time zones but don't necessarily travel. Both types have their advantages, and the choice between them depends primarily on whether you want a watch ready for travel or rather for remote contacts. Both types – True GMT and Caller GMT – can be found in our online watch store, where models await that are suited to both the traveler's lifestyle and people working remotely with partners from different parts of the world
GMT time zone in practice – how to set and use the GMT function in everyday use
Understanding how the GMT function works is one thing, but only its practical use shows how much it can make life easier. Most watches with this complication have three crown positions: the first – for everyday wear, the second – for setting the date and GMT hand, and the third – for adjusting the main time. In practice, setting is straightforward: first you set local time, and then, using the second crown position, you adjust the GMT hand to the second time zone. If the watch has a rotating bezel, you can use it to read yet another time by rotating the ring forward or backward by the appropriate number of hours.
Such a GMT time zone in a watch is a tool you'll appreciate not only during intercontinental flights. It will also be useful if you collaborate with people in other parts of the world, follow sporting events broadcast from another continent, or simply want to know what time it is where someone close to you lives. Interestingly, in many modern GMT watches, this function is not only practical but also aesthetic – the fourth hand and 24-hour scale add character to the dial. Thanks to this, a GMT watch becomes a combination of utility and timeless design that has more to offer than simply measuring time. In our store, you'll find both men's watches and women's watches with GMT function that combine time measurement precision with elegant design and practical application in everyday life.
Krzysztof Szopa
Watch Expert
An expert associated with the WestWatches.pl brand, a place that has been providing watches for every occasion for years. Thanks to many years of experience in the watchmaking and jewelry industry, he passionately shares his knowledge, offering professional advice both in the online and physical store. He specializes in selecting original watches, watch accessories, and jewelry products that combine exceptional quality with competitive prices. His goal is to help customers find the ideal product that will meet their expectations and emphasize their style.
See popular articles
How to Change a Watch Strap? A Simple Step-by-Step Guide
Changing a watch strap is easier than you think – all you need is the right tool, a few careful moves and a new strap that fits the case. On classic models you have to release the spring bars, while a quick-release system lets you do it without any extra tools. The whole process can take just a few minutes, and the result? Your watch gets a completely new look. Find out how to remove the old strap, fit a new one and avoid scratching the case.
Fabric Watch Straps – How Do Perlon, Canvas, Rally and Bund Differ?
A good strap can completely change the look of a watch – but which one should you choose? Perlon is light and breathable, canvas stands out with its woven texture, rally catches the eye with sporty perforations, and bund gives a watch an aviation character. Although they are often mentioned together, not all of them are fabric straps – a rally strap is usually perforated leather, and a bund is a design with an additional pad. Find out how these four styles differ and which one suits your watch best.
NATO Strap – How to Fit It and How Does It Differ from a Zulu? A Practical Guide
A NATO strap is a lightweight fabric watch strap that threads under the case instead of attaching separately on each side. You can fit it yourself in a few simple steps. Compared with a Zulu strap, it is usually thinner, has flatter hardware and an extra layer of material under the watch. Find out how to fit a NATO strap correctly, how the two designs differ and how to choose the right size.
Types of Watch Bracelets – Oyster, Jubilee, President and Mesh. Which One to Choose?
Oyster works for everyday wear, Jubilee adds elegance, President emphasises a luxury character, and mesh offers lightness and flexibility. Each of these constructions sits differently on the wrist and changes the look of the watch. The differences are not just about the number of links, but also about comfort, weight and the type of clasp. Discover the main types of watch bracelets and find out which one best suits your style and your watch case.
GADA – One Watch for Work, Weekends and Travel. How to Choose It?
One watch can go with a shirt, jeans, a blazer and even the swimming pool. That is the whole idea behind GADA (Go Anywhere, Do Anything). Instead of several models for different occasions, you choose one that combines comfort, durability and a timeless look. The safest choice is a steel case of 36–41 mm, 100 m water resistance and a legible dial in a neutral colour. Find out what to look for to choose a watch you will actually wear every day.
Tuxedo Watch – Black Tie and White Tie Rules
Zegarek do smokingu można nosić, ale nie każdy model pasuje do wieczorowej elegancji. Przy dress code black tie najlepiej sprawdzi się cienki zegarek na czarnym skórzanym pasku, schowany pod mankietem koszuli. White tie wymaga większej powściągliwości – do fraka tradycyjnie wybiera się zegarek kieszonkowy albo całkowicie rezygnuje z odmierzania czasu na nadgarstku. Sprawdź, jak dobrać zegarek, żeby zachować zasady etykiety i uniknąć modowego faux pas.
316L, 904L and surgical steel – what is your watch made of?
Most steel watches, from affordable models to luxury constructions, are made of 316L steel. 904L steel contains more nickel, chromium and molybdenum, and therefore offers higher corrosion resistance, but in itself it does not mean greater scratch resistance. The term “surgical steel”, in turn, does not point to one strictly defined alloy. In watches it most often refers to 316L, but without a specific material designation it may simply be a marketing name. If you are choosing a watch for years, look therefore not only at the words “stainless steel”, but also at the grade of steel, which components are made of the given material and how they are finished.
Japanese or Swiss watches? We compare quality, movements and prices
If you are wondering whether Japanese or Swiss watches are better, the name of the country alone will not give you a good answer. In both cases you will find simple models for relatively little money, solid mid-range automatics and designs belonging to the world's watchmaking high end. Far more about quality will be told to you by the specific movement, the way the case and bracelet are made, the crystal, quality control, accuracy and price. Check how Japanese watches really differ from Swiss ones and what to pay attention to before you choose a model for yourself.
The lifespan of a quartz watch – how long does it really last, and when is it no longer worth repairing?
We value quartz watches above all for their accuracy, convenience and modest day-to-day demands. That does not mean, however, that they can run indefinitely and need nothing more than a new battery once every few years. Over time, the components of the movement itself also wear out, and the moment a watch starts giving trouble can look completely different depending on the model, the way it is used and the availability of parts. So how long can a quartz watch last, what wears out in it most often and when does repair still make sense? Check what its lifespan really depends on.