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Garmin Forerunner 945 vs fenix 6 – Which is Right for You?

As you advance in your running, your expectations ab out gear also evolve. Those department-store running shoes are no longer up-to-snuff. Your running shorts now need to be just right. Not just any hat will do. You even start to get picky about gel flavors. As you get more experienced, you realize that everything need to be just right.
This preference for excellence can also impact what you expect from your running watch. While there are many great options that provide a wealth of running and training data, what do you do when you start expecting more? You turn to the top-of-the-line options, and for Garmin, that means the Forerunner 945 and the fenix 6.

Garmin’s Forerunner 945 and fenix 6 are both excellent watches that sport many impressive features. They provide a wealth of data in many different ways, and they do it all well. If you are training or racing, and are looking for a watch that can exceed your expectations and help you crush goals, these are great options.

With the release of the Garmin fenix 6 in 2019, and the Forerunner 945 just a few months prior, Garmin is offering two premium watches with the latest and greatest technology. But they both come at a high price point.

The FR 945 has a smooth look and user experience, additional training features, and improved safety features with incident messaging. The fenix 6 is a rugged, versatile watch that looks as good in the office as it does outside.

If you are a runner, swimmer, cyclist or triathlete who wants a robust watch for a lot of different activities, with detailed stats and features, look no further than these two choices.

Physical description

While the physical size of the watch and user experience are similar, I prefer the looks of the FR 945. Although it only comes in black, the watch face is sleeker, and it weighs less. 

The fenix 6 comes in a variety of sizes, materials, and colors. However, in this review we’ll mostly focus on the fenix 6 (vs the 6S and 6 Pro). The fenix 6’s more industrial look, with metal and exposed screws, isn’t as sleek as the slimmer, plastic FR 945. But if you need a more rugged watch and prefer metal construction, then the fenix is your better option.

The silicone straps on both are very comfortable, but so far there aren’t many aftermarket bands with Garmin’s signature quick-release convenience. It’s also a bit of a pain to change out the bands.


The fenix 6’s rugged build results in a watch that is a little heavier than average. Although they look similar in size, at 80 grams it is noticeably heavier than the 50-gram FR 945. 

Both of the watches are very comfortable to wear, but the weight of the fenix 6 can be noticeable when you are moving around during a workout.

Screen size & resolution

The Forerunner 945 has a screen resolution of 240 pixels and a 1.2-inch screen. The fenix 6 has a 260-pixel resolution and a 1.3-inch screen.

The fenix 6 is also a shade thicker at 14.7 mm, compared to the FR 945 at 13.7 mm.

Battery life

The short answer is that battery life on both models is about the same.

But once you dig into some of the advanced battery features on the fenix 6, things get a little more nuanced.

If you just use each watch as a smartwatch, you’ll get up to 14 days of battery life with each. Switch over to GPS mode and you’ll get 36 hours. GPS with music (only available on the fenix 6 Pro) reduces battery life further to about 10 hours.

But new in the fenix 6 are power management options to customize which features you want turned on or off. This means you can see which features are the biggest battery drains, and turn those on and off. Even better, you can do this on the fly if you are running low on battery during a workout.

With so much customization, the battery life swings in the fenix 6’s favor. Because all things being equal, having the option to choose what features you want and don’t want in order to preserve power is a step above the (still great) battery in the 945.

One other feature to mention is solar power, found exclusively in the fenix 6X Pro. We’re mainly focusing on the fenix 6 in this article, but if you upgrade to the 6X, it has solar strips to charge on the go. This won’t fully charge or prevent battery drain – but it will extend the life of the battery for longer use.

Forerunner 945

Buttons and user experience 

The user experience is similar between the FR 945 and fenix 6. The software interface has been improved slightly on the FR 945. However, the button interfaces are the same. You have 3 buttons on the left side of the watch and 2 on the right. They are easy to press but not overly sensitive. 

The interface is similar across the Garmin line, so if you’ve used a Garmin before, you won’t need much adjustment. 

The left buttons act as start (top left) and stop (bottom left). The buttons on the right side scroll up and down, respectively.  

You have a lot of different watch faces to choose from, and you can customize almost everything about the display, from the layout to adding photos from your phone. Note that neither watch is touchscreen. 

You can also customize how you want your apps and widgets to display. With so many options, I recommend setting up which ones you will be using the most and moving those to the top of the list to make navigating through the menu easier. You’re able to display up to 4 data fields on a screen for tracking workouts.


I love the versatility of both the FR 945 and fenix 6. If there is an activity you want to track, it can probably do it.

If there isn’t a preset, you can set up a profile for a custom activity. But the preset probably already exists. Check out the Connect IQ store to download apps like the 7-minute full-body workout.

There are a few activities pre-loaded onto the fenix 6 that you don’t find on the 945. This includes mountain biking, jumpmaster, and tactical. Jumpmaster and tactical are commonly used for military personnel (jumpmaster is for use while skydiving and tactical provides enhanced waypoint navigation).


Both watches have four different run profiles to select before your workout: running, indoor track running, treadmill running, and trail running.

For outdoor runs, standard stats include GPS-based distance, time and pace. You’ll also get cadence (steps per minute) and a comparison between your current stats (during an intense run) and your average fitness level. 

Garmin switched over to a Sony GPS chip to extend the battery life of their watches. The GPS is decent overall, but some runners complain of small inaccuracies for outdoor runs (it should be noted that all consumer GPS devices are slightly inaccurate to varying degrees). You’ll get a summary of your workout that includes training effect, VO2Max, recovery, and training status. 

For indoor running, GPS is turned off. Your speed, distance, and cadence are all calculated with the accelerometer, which when we tested, was very accurate. You can also calibrate treadmill runs after you run at least a mile.

A new feature for the fenix 6 is PacePro. Note: this feature is slightly different on the fenix 6 vs 6 Pro. But they essentially do the same thing by offering customized pace guidance based on elevation and personal preference. Anyone who has tried to maintain a regular pace on a hilly course knows it’s impossible to run even splits. 

PacePro helps you figure out what pace you should be running based on how long and steep your climb is. 

You can control how hard you want to run hills as well as whether you are aiming for negative splits. PacePro will determine which pace is right for you.

fenix 6


The cycling maps are slightly better on the FR945. Otherwise, you get all the same features. 

Both watches are compatible with ANT+ accessories such as a cadence sensor or power meter. 

It’s worth noting that if you turn off GPS while cycling, you won’t get speed or distance data without additional sensors.


Garmin armed both watches with great features for both indoor and outdoor swims. The watches are similar in terms of swimming features. The main difference is the rated water depth. The sturdier fenix 6 is rated to 100m, while the FR 945 is rated to 50m.

No matter where you swim, both watches will recognize your stroke type. For indoor swims, lap and distance tracking come standard.

For serious training in the water, you get Garmin’s drill mode feature on both watches. This ensures that you still count your laps when arm stroke is impacted by later manually entering or confirming the distance after your swim. 

For heart rate monitoring, the advantage goes to the fenix 6, which can track wrist heart rate underwater.

For the 945, you’ll need either the ANT+ accessory HRM-TRI for open water or HRM-SWIM for indoor swimming. 

One additional detail is that the HRM straps store your heart rate info, but you can’t view it in progress. With the fenix 6, you can view heart rate in real-time.


Triathlon mode allows you to quickly transition to each sport, so you can run, cycle, and swim by simply transitioning at the push of a button. Both watches work well for triathletes; however, the fenix 6 is thicker, making it fractionally harder to pull a wetsuit over during a race.


With the new navigational waypoints loaded for both watches, you will have no problem exploring on a walk or hike without getting lost. The Auto climb feature also allows you to detect changes in elevation automatically.


You can track a variety of different activities in the gym with both watches. From strength training to cardio and elliptical training, stair-stepping, indoor rowing and even yoga profiles, you’ll accurately capture your workouts.


Garmin beefed up their sensors in both the FR945 and fenix 6, focusing on the optical heart rate monitor.

Heart rate monitor

Garmin added the ELEVATE optical heart rate sensor on both watches. It is very accurate, and provides users with new features.

Pulse OX is a niche but nonetheless useful new feature. This measures your blood oxygenation levels every 15 minutes for acclimating to altitude training. This is especially helpful when you’re pushing yourself, so you can tailor your workouts to increase your body’s VO2 max. Key stats to watch out for include your SPo2 falling below 95%. You also get advanced sleep statistics from this feature. 

Aside from SPo2 levels, you get a lot of different features when it comes to using your heart rate information. These include autodetecting your maximum heart rate, heart rate reserve, and lactate threshold heart rate, giving you an idea of when your muscles start to fatigue, and helping you run smarter. 

You can set heart rate alerts for leaving your target heart rate zone, but be sure to do so before your run.

My favorite feature on these watches is the recovery time estimator, showing you how much time you need between hard efforts. There’s even a stress test to give you an estimated stress level in the form of a graph over the past 4 hours. I like the related breathing activity as a relaxation technique.

And as mentioned above, wrist heart rate works underwater on the fenix 6, but not the Forerunner 945.


The accelerometer on both watches is very accurate. It’s self-calibrating, and the accuracy of your speed, distance, and cadence all improve the more you use it for running with GPS turned off.

With the built-in altimeter and compass on both watches, you also get extremely accurate elevation and direction data.


Both the FR 945 and fenix 6 have really good training features to help improve your runs. Garmin has added a few training features to the FR 945, but for the most part, they are similar.

Interval training and advanced workouts

If you’re at a point in your running where you need either one of these watches, you surely know the benefits of interval training. Both watches make it easy to create workouts based on distance or time. Once you set up a custom workout, your watch will keep that version until you make another. The open interval option helps you with track workouts or for a set distance. 

Access to Garmin Coach is included with both watches, giving you professionally-designed workouts and training plans for running goals from 5k and 10k up to full marathons. Your plan adjusts dynamically based on your performance, and even with a missed workout. You’ll also get videos and running tips in the Garmin Connect app. 

While this only applies to running right now, many athletes have asked for cycling workouts, so it could be around the corner.

Training status & load

Both watches have training load, letting you look at the past 7 days or 4 weeks. The watches balance out your workouts to focus on a mixture of intensity and distance, and actually tell you what kind of runs you should add to your routine. 

They also have heat and altitude acclimation features that tell you how long it will take to adjust to higher elevation or temperatures. If you travel a lot, this is a great feature. The VO2Max takes into account the heat and altitude, and adjusts based on where you are. This is great for race predictions, as you’ll get estimated times for your 5k, 10k, half-marathon and marathon runs.

Training effect also goes into more detail than before, telling you your specific training load for an individual workout, as well as the aerobic and anaerobic benefits.

Virtual partner

Also available in both watches is the Virtual Partner training feature. Designed to help you meet goals, the virtual partner lets you race against yourself for distance, time, pace, or speed goals. 

You can choose a desired pace or race against something you already recorded. It shows you how far ahead or behind you are, giving you real-time feedback about whether you are meeting your goal.

Mapping / Navigation

The fenix 6 and FR 945 have full-color, detailed topographical maps for the region where you purchased the watch. You can see the terrain around you as context from your surroundings with points of interest, which is very helpful for hiking. 

For running and cycling, with the round trip features the watches will calculate 3 different possible courses based on how far you want to run or bike. 

If you are following a predetermined course, both watches will give you instructions on when to turn and tell you when you’ve gone off route.


These watches both come with some great extra features. For starters, being able to go for a run without carrying cash is a great option with Garmin Pay, their NFC payment feature.

Phone notifications

As soon as you connect to your phone, you’ll start receiving notifications. This feature is standard across Garmin devices. They pop up over everything, but are easy to dismiss. You can also open the notification to get more detail. 

The new privacy mode on these watches keeps notifications private. They won’t appear unless you press a button or turn the watch towards you.

Music storage/playback

Another favorite part about these watches is the ability to leave your phone behind and still play music.

While music support is not available with the fenix 6, you can get it with the fenix 6 Pro. The FR 945 has 14.5 GB worth of storage – you can expect to access about 40-50% of this total storage for music. The fenix 6 Pro measures this by saying it holds 2,000 songs. 

You simply preload your watch with your own music, and play the music through a Bluetooth device. You can also load iHeartradio, Spotify, and Deezer in advance, downloading through wifi. If you connect to your phone via Bluetooth you can control music playing from your phone. 

Some runners have noted spotty issues with Bluetooth headset connectivity, especially if the Bluetooth receiver of your headset is opposite the wrist you wear your watch on (ie: you wear your watch on your left wrist and have Bluetooth headphones with a receiver on your right ear).

Safety and tracking features

The tracking features are pretty much the same for these two watches. 

The FR 945 and fenix 6 automatically detect if you collapse while running or crash your bike, and sends a message to your predefined emergency contacts. It is key to note that you must have your phone for these features to work. 

You can also set up a message ahead of time to send at the click of a button. Live tracking will automatically start after this message has been sent. 

Live tracking is enabled with both watches, so you can choose who to share your location with, and they can see your position in real-time. Keep in mind they can also see your distance, speed, elevation, and any additional sensors recording data. 

I really like the group track feature with Garmin. As long as you both are connected via Garmin Connections, have your phone with you, and have cell service, you can keep track of training partners through position sharing.

Compatible Accessories

Accessories and sensors are identical between the FR 945 and fenix 6. There’s a wide range of options, and that includes everything ANT+ you could want.

Running Dynamics Pod

You need the HRM-Run accessory, but once you connect a running dynamics pod, you get great information on how you run with both watches.

The stats you can track include your ground contact time and balance (for running symmetry), stride length, vertical oscillation and ratio (how much bounce is in your running motion with a cost-benefit ratio).

Paying special attention to symmetry, you can learn about your form and what improvements to make, from the length of your stride to how quickly you step.


We’ve chosen to focus on the fenix 6 and Forerunner 945 because they currently cost the same amount: $600. As we’ve alluded to, other variations of the fenix 6 including the 6 Pro and 6X Pro offer more features than both of these, but come at a steeper price. 

While these watches are very similar, how you use the watch will determine your best buy. You can predict performance, analyze training, and understand your form with both watches.  

If you want a sleek everyday-wear watch that’s lightweight, then the FR 945 is your go-to. If you need more rugged construction, opt for the fenix 6.

Garmin Forerunner 945

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Garmin fenix 6

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The Wired Runner