To be fair, bezel utility doesn’t strictly count as a complication, as it works independently of the movement inside of the watch. Still, these tools have become so commonplace, most people that own more than one watch likely have one with an extra bezel function. As such, we’ve taken it upon ourselves to put together a collection of some of the most common bezel functions and have explained a little bit on how each works. The following article encompasses how to read a watch bezel.

Wearable timepieces (or wristwatches , as they are better-known), were created to give us an easy method by which to judge the time of day while on-the-go. What you might not know is that anything a watch can do operationally, outside of just telling normal time, is called a complication. Funny thing is, it’s seeming more and more that watches with complications are outnumbering those without, so we hoped to enlighten you as to the purpose, history, and functionality of these additional uses.

Now, most watch brands (especially the ones with larger catalogs) have at least one watch with secondary bezel functionality. A similar number, if perhaps a bit lower, also make watches in which the bezel utility is incorporated into the function of the movement of the watch. Whatever the case, one thing is for sure: the bezel as a watch tool is here to stay and we wouldn’t be surprised if you already own a wearable timepiece with a functional bezel.

It’s hard to trace back the exact origins of the watch bezel’s incorporation into watch functionality, but it likely started around the 1950s (the same decade in which the GMT watch was born). The idea was pretty brilliant in its simplicity: all watches have bezels, so why not use them for something other than simply to surround a watch dial? A bezel could have markings etched upon it to add utility to the watch without actually having to change how the watch operates. This increased the value proposition of a wearable timepiece by a great deal without actually increasing the cost to build it, so it should come as no surprise that the idea caught on.

Common Bezel Types And How They Work

As is the case with most watch functionalities, the type of wristwatch you get is going to determine how the accompanying bezel works. Now, this is not a strict law, but it’s a pretty good bet that if you have a dive watch – for instance – the included bezel will feature an elapsed time or countdown bezel. And that’s because the pairing makes sense – a dive watch is intended for diving and, as air-breathing mammals, we humans need to know when our scuba tanks are empty so that we might to resurface and avoid drowning.

It can also be said that, for some watches, the bezel functionality is inherent to the watch’s overall function – as is the case with most GMT watches. This is, however, much rarer than watch bezels with what one might call “bonus features.” Still, it’s important that you become acquainted with the types of watches available so as to ensure that you’re getting yourself one with the proper utility. In any case, the following are the most common types of watch bezels and how they work.

Compass

Casio Twin Sensor Digital Watch ($41)

While there are a small number of watches that have compass markings painted or engraved upon their bezel, you can actually use any analog wristwatch as a makeshift compass in a pinch – so long as it is daytime. Simply point the hour hand in the direction of the sun and take note of the distance between the hour hand and 12:00. Halfway between the markers is South, so long as you’re in the Northern Hemisphere. For the southern hemisphere, follow the same process, only you’ll want to use the 6 o’clock position rather than 12.

If you have a watch with an actual compass bezel, once you find south following the same process, you can simply twist the bezel so that the big S (you know, the one that stands for ‘south’) is pointed toward south. You’ll still have to check your bearings every so often to make sure you haven’t veered off course, but it’s still easier than doing it entirely manually. Just keep in mind that this will not give you exact or precise directions, as there’s room for human error and the position of the sun changes depending upon the time of year and your location, but it’s still helpful as a roundabout method of navigation.

Elapsed Time

Seiko SSC017 Prospex Dive Watch ($239)

Most commonly associated with dive watches, elapsed time bezels, most often, feature markings that line up with the minutes on the dial. They differ in that they don’t have hour numerals, but rather numbers that correspond with the minutes with which they line up (when in the neutral position). Dive watches also most frequently feature unidirectional movement – meaning they spin, but only counterclockwise, which works as a safety feature.

You see, dive watches were created before scuba gear featured timer dials – meaning anyone using one didn’t have an exact idea as to how much time they had left in their oxygen tanks. By using a dive watch, divers had a quick and easy reference on their wrist that could let them know how long they had until it was time to surface. The way to use it is simple: just rotate the bezel until the 0 marker lines up with the minute hand. This is your starting marker. Then you can just reference it whenever you want to see how much time has gone by. For reference, these bezels only rotate counterclockwise because, if you bump it while you are diving, the rotation will only reflect that more time has elapsed and not less – avoiding a potentially catastrophic accident, like running out of air because you thought you had more time.

Countdown Timer

Nixon Ranger Chronograph Watch ($400)

Functionally similar to an elapsed time bezel, countdown timer bezels have one very distinct difference: rather than the numbers counting up from 0 to 60 around the dial clockwise, they count down from 60 to 0. This is beneficial for anyone that needs to synchronize their watches with others – such as pilots, military, or police – and can also function as a racing timer for runners, cyclists, or anyone else trying to beat their best time. Countdown timers work virtually the same as elapsed time bezels, except for slight operational differences. For instance, countdown timers often rotate both clockwise and counterclockwise (whereas elapsed timers typically only rotate counterclockwise). It’s also important to note that, in order to use a countdown bezel, you’d want to set the bezel time you wish to track at the point of the minute hand. That means, if you want to measure ten minutes, you’d set the 10 position on the bezel to line up with wherever the minute hand is and, in ten minutes, the minute hand will point at zero.

GMT/2nd Timezone

Victorinox 241648 Infantry GMT Watch ($450)

GMT bezels are one of the few on this list that require cooperation with a watch’s internal movement in order to work properly. And this is for one simple reason: GMT dials – which allow you to track two timezones at one time – read on a 24-hour scale, whereas a normal watch dial works in 12-hour increments. So, most GMT watches feature an extra hand (in addition to hours, minutes, and seconds) that rotates around the dial once every 24 hours, indicating a corresponding time marked on the surrounding bezel.

Some GMT watches feature a stationary bezel with a zero marking at the 12 o’clock position and 1-23 markings around the watch ascending clockwise – these require you to set your GMT watch hand to the corresponding time, which is usually controlled mechanically via the crown. Other GMT watches feature a rotating bezel with the same 24-hour markings, except that you can alter the tracked timezone simply by rotating the bezel rather than the GMT hand. Just remember, either way, the secondary timezone will be read in 24-hours, so you’ll want to brush up on how to read military time if you’re looking to get a GMT watch.

Tachymeter

Shinola Limited Edition Rambler 600 Watch ($1,325)

One of the most common bezel types – due to its inclusion in many chronograph watches – the tachymeter is a clever addition that allows the user to track the speed of anything – most typically cars and/or airplanes – and can also track the rate of accumulation of anything, so long as the measured period occurs over the course of approximately 10 seconds and up to a minute – this is because the second hand (which is the measuring tool) rotates around the watch in 1-minute intervals and most tachymeter bezel markings start at around the 7.2-second mark. This is because anything that happens in less than that time is much too difficult to accurately measure by eyeballing it (a result of the rapidity of the action).

It works like this: the bezel of the tachymeter features counterclockwise-ascending markings around the edge, each a bit closer to the next than the last, which are typically marked in intervals of 1, 5, 10, 25, 50, and 100. And using them is actually quite simple, once you understand the formula. You just need one known factor – be it distance, speed, etc. For example, if you know that you are traveling for one mile, start your travel when the second hand hits the 0 position (you can use a splice function to stop the second hand at 0) and stop it again once you’ve reached a mile. Let’s say, for instance, that one mile of travel took you 30 seconds. Well, if you look at the 30-second position on the outer bezel, you’ll notice that the marking reads 120. This means you were traveling at a speed of 120 miles per hour.

Similarly, if you know your speed, you can track your distance using a similar formula. Say you are traveling at 80 miles per hour. Well, start your travel at the 0 position, wait until the second hand reaches the 80 position on the bezel (which corresponds to the 9 o’clock position on the dial) and then – so long as your speed remained constant – you’ve traveled exactly one mile. For fractional travel – for instance, a half-mile sprint – you just need to be sure to divide by the fraction. So, a 16 second half-mile would be 225 divided by 2, resulting in an average speed of 127.5 mph. Extrapolate that formula and you can figure out the rate of just about anything.

Telemeter

Alpina Alpiner Chronograph Watch ($1,072)

Similar in operation to the tachymeter, the telemeter was originally invented to give soldiers the ability to gauge the distance of enemy fire. That means it is used to calculate relative distance to something that can be both observed and heard. Today it is most commonly used by your average person to judge the distance of thunderstorms. It works like this: set your second hand at the 0 position, start it when you see a flash of light, and stop it when you hear the thunder boom. The reading along the outer bezel will give you the distance to the storm (or the enemy). Just remember that telemeter bezels are set measurements – so you can have one in kilometers, miles, or – on rare occasions – both, but they cannot be altered to measure in different units.

Pulsometer

Bell & Ross BR V2-94 Garde-Cotes Watch ($4,600)

Another fixed bezel measurement scale, the pulsometer dates back to around the 1940s with its original intended users being medical professionals. You see, the pulsometer (as its name might suggest) is used to measure one very specific thing: a persons pulse rate. Start tracking when the second hand reaches 0 and stop tracking when the number of beats hits the set scale – indicated on the bezel and typically somewhere between 10-30 beats. Once the pulse beats have reached that number, use the outer scale to gauge the pulse rate per minute. Nowadays, pulsometers are fairly few and far between, but you can still see them here and there on watches that are intended to be used by first responders and emergency personnel.

Slide Rule

Breitling Navitimer World Watch ($4,675)

The only bezel on our list that doesn’t incorporate the movement of the watch hands in its operation, the slide rule is an incredibly helpful calculation tool. It’s comprised of two parts, an inner fixed scale and an outer rotating scale that, when corresponded, act kind of like a wrist-mounted calculator. These are especially helpful for quick calculations that are needed when a smartphone or digital calculator are otherwise inaccessible.

For reference, let’s say you want to multiply 4 by 16 (for whatever reason). Line up the 16 marking on the outer bezel with the 10 marking on the inner bezel (this is the base conversion factor). Then, find the 4 marker on the inside bezel and look at the number opposite it: 64. Division follows a similar process and, in fact, a slide rule can actually be used to determine ratios, speed, mileage, square roots, and a whole lot more – so long as the necessary markings are included on the inner bezel ring. These functionalities, however, can get a bit complicated and require a good deal of mental hopscotch in order to gauge them properly.