Polar Grit X or Garmin Fenix 6? Comparison of important Differences

Our Polar Grit X or Garmin Fenix 6 comparison shows important differences and gives tips on choosing the right model. We have been reviewing these sports watches for quite some time now and know where the important differences between them lie, even those that cannot be found out through the manufacturer’s website.

Here you can find our detailed individual reviews:

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Polar Grit X or Garmin Fenix 6?

As our Polar Grit X versus Garmin Fenix 6 comparison will show in a moment, the two sports watches Polar Grit X and Garmin Fenix 6 cannot be compared easily. While the Grit X has only one fully featured model to choose from, athletes are spoiled for choice with the Fenix 6 from an entire model series, because there are numerous variants available, which differ from each other in hardware and software features. All in all, both products offer many features that would go beyond the scope of this article. We will therefore go into the most important aspects and compare the smartwatches in a detailed table at the bottom of the article.

Comparison: Polar Grit X versus Garmin Fenix ​​6
Comparison: Polar Grit X versus Garmin Fenix ​​6

If in the end the interest in a Fenix ​​6 predominates, the prospective customer may take a closer look at the available variants. But also for this we offer below a comparison of the most common model variants. In addition, more details can be found in the separate Garmin Fenix 6 comparison, which takes a closer look at the variants and breaks them down very precisely.

If you are more interested in the Polar Grit X, you can alternatively choose the comparable multi-sport watch Polar Vantage V. However, the Grit X offers significantly more features (hardware and software) except for the features Recovery Pro and orthostatic test, which are only available on the Vantage V. Together with the Polar H10 HR Chest Strap, a recovery analysis is created, which is especially interesting for professional athletes. It helps to find the right balance between training and recovery. For these models we also offer a separate Polar Grit X versus Vantage (V and M) comparison with important differences.

Polar Grit X versus Garmin Fenix 6 (short overview)
 Polar Grit XGarmin Fenix 6
Polar Grit XGarmin Fenix 6
Weight (gram)64starting from 58
WaterproofWR100 (100 m)10 ATM (100 m)
Battery life
Watch Mode | GPS
7d | 100h9d - 21d | 25h - 148HRS
(depending on model)
Our ReviewPolar Grit XGarmin Fenix 6
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Design and Size

All of high quality

Let’s start with the Polar Grit X versus Garmin Fenix 6 comparison of look and feel. All models appear high-quality and very well manufactured. Due to the material selection of the manufacturers, all models are also suitable for intensive outdoor activities.

While the Grit X is equipped with a robust stainless steel housing and a fiberglass-reinforced polymer back cover, the materials used for the Fenix 6 series are model-specific. The display of the Grit X is a laminated gorilla laminated glass with anti-fingerprint coating. There were actually only a few smear marks on the display in our review.

The bezel of the Fenix 6 series can be either stainless steel, titanium or titanium with DLC coating and the case material can be fiber reinforced polymer with metal case on the back or also stainless steel, titanium or steel with DLC coating. Furthermore, the Fenix 6 offers a choice of scratch-resistant sapphire crystal or Corning Gorilla Glass 3. These combinations have a strong impact on the Fenix 6’s price.

A lot of choice with the Fenix 6

If you want the model with the largest case and display, the Fenix 6X Pro is the right choice. With a display size of 35.56 mm diameter (1.40 inches), it also towers above the Grit X (1.2 inches). Its resolution is also significantly higher at 280 x 280 pixels. A Fenix 6 Pro, for example, offers 260 x 260 pixels, the Grit X or Fenix 6S 240 x 240 pixels.

For those who have a narrower wrist or want a less bulky housing, the flatter and smaller Fenix 6S or 6S Pro is perfect. This was developed by Garmin especially for this purpose without saving on features. So they offer everything that the larger versions also offer. It should be noted that the battery life is a bit shorter, because the built-in battery is also smaller. The Grit X is only available in one size, which is comparable to the Fenix 6 Pro.

All models have 5 mechanical buttons that come with a good pressure point. The Grit X, however, has a slight advantage because its keys are covered with a ribbed structure. This makes the keys adhere better to the skin and is very easy to feel.

All variants are delivered from the factory with sports-suitable, interchangeable (silicone) bracelets with a quick-release mechanism. This makes them more flexible and allows them to be exchanged in the twinkling of an eye without tools for almost any watch strap with matching spring bars.

We summarize

  • All models offer a high-quality look, the workmanship is excellent
  • The look of all can be quickly adjusted with the help of Quick Release wristbands
  • Some variants of the Fenix 6 offer more noble materials for housing and display
  • Among the variants of the Fenix 6 there is always a suitable model for the wrist
  • The Grit X offers the best control buttons

Display and Operation

In the Polar Grit X or Garmin Fenix 6 comparison we also look at the differences in the displays. The color displays of all models are comparable. Although there are differences in resolution and size (see table), they feel great outdoors and in bright environments. There they are very good and easy to read. In very dark environments the displays are a bit harder to read, but they are supported by a backlight that can be activated. An automatic system switches them on reliably with a corresponding arm movement. All models have a permanently switched on Always-On-Display, which is almost always immediately readable.

The Grit X is the only one in the field to offer a touch display that makes the smartwatch easier to use, especially in everyday life. Due to the touch display, a second operating option is thus available. Wiping on the display can be more pleasant – although sometimes only at the second attempt – especially when navigating through the menus for a longer time. During sports, the touch function is switched off, so that the display is operated via the keys, as with the Fenix 6.

The menu navigation is a bit better on the Fenix 6, but overall all models offer quite intuitive operation after a period of getting used to them.

We summarize

  • All models are equipped with 5 very good mechanical keys
  • All models offer a very good color display for outdoor activities
  • All models offer a backlight
  • The Grit X has a touch display
  • The Fenix 6 offers different technical display features depending on the size

Grit X or Fenix 6 Comparison: Battery Life

Let’s take a look at the battery life in the Grit X or Fenix 6 comparison. These are sometimes quite different.

Polar Grit X

With the Grit X, the battery life characteristics can be summarized quite simply. In normal watch mode with all available features (activity tracker, sleep tracker, 24×7 heart rate measurement, smartphone messages) and every 2 to 3 days of training at about 30-45 minutes with animated FitSpark strength exercises or GPS activities, 6 to 7 days are possible.

In training mode, several configurable energy saving options are available to extend the battery life to up to 60, 65 or even 100 hours including GPS. Energy saving options that can be influenced include settings for the GPS recording rate and the integrated heart rate monitor. In addition, a kind of screen saver can ensure a minimum of display activity by only showing the time during activities.

Once a change has been made, the smartwatch will show the effect on the remaining battery life. This means that athletes can quickly estimate how long the watch will last. Depending on the selected option, less GPS tracking points (1 minute, 2 minutes or off) are recorded, less data is shown on the display or the optical heart rate sensor is deactivated completely. Alternatively, a more energy-saving Bluetooth HR chest strap can be permanently integrated. If the screen saver has been activated, all training data can still be accessed for 8 seconds if necessary before they disappear from the display.

Garmin Fenix 6

The battery life of the Fenix 6 is highly dependent on the choice of model. However, the Fenix 6 series is ahead overall. Because even the smallest model Fenix 6S is 9 days in clock mode and all available features. The larger models even manage up to 21 days.

In training mode including GPS, between 25 and 148 hours are also possible depending on the model. The Fenix 6 also offers a power manager for energy saving options. This is available on all models. Just like the Grit X, the remaining estimated battery life is recalculated and shown in real time on the display.

If extremely long battery life is an important criterion, you should actually keep an eye on the not exactly cheap Fenix 6X Pro or even the 6X Pro Solar (both 51 mm), as their battery life is considerably better, but the smartwatch is bigger and heavier. The solar model has a special power glass display, which under certain conditions can improve the battery life with the help of solar energy.

We summarize

  • All models offer a power manager
  • The battery life in training mode is very good to excellent for all
  • The Fenix 6 series offers the better battery life

Alarms, Sensors and Interfaces

In the Polar Grit X versus Garmin Fenix 6 comparison, the models of the manufacturer Garmin are ahead of the others. Some of the similarities are:

  • GPS, GLONASS, Galileo for the positioning functions
  • Acoustic, visual and vibration alarms and alerts
  • Bluetooth Smart for the coupling of running sensors, HR chest belt sensors, bike speed/cadence sensors
  • Bluetooth Smart for smartphone connectivity/synchronization with the app/smartphone notifications
  • Accelerometer
  • Compass

The Fenix 6 series offers the following additional features compared to the Grit X:

  • ANT+ for the coupling of running, cycling and HR chest belt sensors, power meters, speed/cadence sensors and more
  • Bluetooth Smart for Power Meter pairing
  • Sensors for the detection of a fall ((automatic) accident notification assistant)
  • WLAN for synchronization with Garmin Connect (past the smartphone)
  • Pulse oximeter, which can estimate the oxygen saturation of the blood (SpO2) directly on the wrist. The measurement can be taken automatically if required or during sleep. The measurements can provide indications of sleep disturbances/sleep apnea, so that if there is any suspicion, this can be examined more closely by a specialist.
  • Fenix 6 Pro models: integrated music memory and the option to connect Bluetooth headphones directly to the smartwatch. This allows the smartphone to stay at home during sports.

We summarize

  • In terms of sensors and interfaces, the Garmin Fenix 6 is clearly ahead.

Accuracy of GPS and heart rate sensor

For the Polar Grit X or Garmin Fenix 6 comparison, we also have data from our individual tests on the accuracy of the GPS and heart rate sensor. The Grit X has 10 active LEDs: 5 red, 4 orange, 1 green. Especially the red and orange LEDs promise better results for darker skin types.

Polar Grit X

Polar Grit X (red) vs HR10 chest strap (blue)
Polar Grit X (red) vs HR10 chest strap (blue)

With constant running units, the Grit X leaves a good impression. At the same time, the Polar H10 chest strap was worn for a first jogging unit to counter measure. The result can be seen in the graphic. As can be seen, the almost training-free time has left its mark in the crisis of 2020. It is praiseworthy that the Grit X pulls along properly from the beginning.

Polar Grit X: HR-Measurement accuracy
Polar Grit XPolar H10
HR  Average (S/min)156156
HR Max. (S/min)168169

With the Polar Grit X, we are still lacking comparative measurements to interval training, which is because it is still comparatively new. We will provide these data as soon as we have more.

Let’s have a look at how the Polar Grit X processes GPS data. All in all, it maps routes properly and stays within the 10 to 15 meters of tolerance allowed to GPS receivers in the consumer segment.

Garmin Fenix 6

Garmin Fenix 6 Pro Test: pulse/heart rate accuracy (Fenix 6 Pro: purple, Polar H10: blue)
Garmin Fenix 6 Pro Test: pulse/heart rate accuracy (Fenix 6 Pro: purple, Polar H10: blue)

Also during the Fenix 6 Pro testing, our Polar H10 HR chest strap was also present. This allows us to check if the smartwatch measures the heart rate accurately. The two measurement curves superimposed on each other over time look almost identical, as can be seen in the graphic (Garmin Fenix 6 Pro: purple, Polar H10: blue). All in all, this all-rounder does not afford to make any major mistakes. However, the Fenix 6 has some HR tops that do not belong there.

Garmin Fenix 6 Pro: HR-Measurement accuracy
Garmin Fenix 6 ProPolar H10
HR  Average (S/min)158156
HR Max. (S/min)180178

With the Fenix 6 we could observe good to very good measurements during a small interval training, except for a few spots. The Fenix 6 performs well especially during the increases in intensity and only shows delayed readings in the breaks, when the heart rate gets slower and slower.

Garmin Fenix 6 Test Interval Training: blue: Fenix 6, red: Polar H10 HR-chest strapt
Garmin Fenix 6 Test Interval Training: blue: Fenix 6, red: Polar H10 HR-chest strapt

The average values look very good. The Fenix 6 shows itself at its best during interval training and proves that proper training is possible without a chest strap:

Garmin Fenix 6 Pro: HR-Measurement accuracy interval training
Garmin Fenix 6 ProPolar H10
HR  Average (S/min)146145
HR Max. (S/min)165165

In a test over 7 km running the Fenix 6 Pro shows what it can do from a GPS point of view. It only allows itself very few inaccuracies (for example at the very beginning of the training in the first meters) and convinces for the most part. A large part of the total distance looks like this:

Garmin Fenix 6 Test: GPS Accuracy
Garmin Fenix 6 Test: GPS Accuracy

We summarize

  • Polar Grit X and Garmin Fenix 6 provide comparably good results regarding heart rate monitor and GPS accuracy. All details can be found in the individual tests.
  • The Polar Grit X promises better results for darker skin types, especially due to its high number of red and orange LEDs.


Sports and Fitness

Polar Grit X and Garmin Fenix 6 support structured training plans and calendars. These can be loaded directly onto the smartwatch and followed from there. For running, there are particularly good training options for all of them, so that it is possible to prepare for a competition or the goal of increasing the performance level.

A multi-sport mode is also available on all smartwatches, which is very popular with triathletes, for example. It allows different activities to be recorded as a coherent unit. All smartwatches also feature animated fitness exercises for in between.

But there are also many differences in the features. The Polar Grit X offers some new features for outdoor activities that are currently exclusive to the Polar Grit X:

  • Running Power on the wrist: provides insight into the intensity of running units without additional sensors.
  • Hill Splitter: Uphill and downhill analysis of an activity. It automatically recognizes ascents and descents using various metrics such as speed, distance and altitude data and divides them into an uphill and a downhill sequence. The Hill Splitter provides a detailed overview of the performance during strenuous altitude-heavy activity sequences. The corresponding performances can thus be compared and improvements made visible.
  • FuelWise: a configurable assistant, which supports you to take care of your energy reserves and to refill calories and fluids in time, especially during longer sports activities. The Fenix 6 offers only manual tracking of water consumption or during activities simple, self-created memories.
  • Komoot support: Plan routes and use them for turn-by-turn navigation on the display.

The Garmin Fenix ​​6 series also offers many features that are not found on the Grit X. Below are just a few of them:

  • Customizability: Sports profiles, data fields, display layouts and alarms can be configured in detail. Above all, alarms can be used to track even the most individual goals: Various heart rate alarms, speed, time, distance, cadence, performance alarms, user-defined alarms such as drinking, eating, turning around, going home.
  • Full size cards: (Pro versions only) Pre-installed TopoActive Europe map for perfect orientation and navigation and over 41,000 international golf courses. New are additional 2.000 ski area maps worldwide with slope information and difficulties.
  • More navigation options (Pro variants only) such as point-to-point navigation or round trip routing
  • Pace Pro (Pro variants only): A dynamic pace setting that takes into account the route profile and whether you want to tackle the climbs moderately or ambitiously.
  • ClimbPro: Automatically obtains data on gradient, distance and altitude before steep climbs.
  • Pulse Ox Sensor: Estimate the oxygen content in the blood to check the acclimatization at altitude or to detect possible breathing difficulties during sleep.
  • Expandable with Sport apps from our own Garmin Store
  • Smartphone messages also possible during an activity. This is not possible on the Grit X.
  • Power Glass (solar version only): transparent solar charging lens through which the watch absorbs sunlight under certain conditions and charges the battery while the watch is in use.

We summarize

  • With the features offered, everyone has to see for themselves what they really need
  • Structured training is possible with all sports smartwatches
  • Advanced analysis of training load is available for all
  • The adaptability and expandability of the Fenix 6 is very good
  • For skiers, golfers, water sports enthusiasts and anglers, the Fenix 6 is more interesting due to its features
  • If you want it to be easier, you should rather look at Grit X

Polar Grit X or Garmin Fenix 6: detailed comparison

Finally, we will compare the Polar Grit X and the most popular Garmin Fenix 6 variants directly with each other and compare the most important differences in table form:

Polar Grit X vs Garmin Fenix 6s vs Fenix 6 vs Fenix 6s Pro vs Fenix 6 Pro vs Fenix 6X Pro (Detailliert)
Weight (gram)645880618393
Housing size (mm)474247424751
Display diagonal1,2" | 30,4 mm1,2" | 30,4 mm1,3" | 33,02 mm1,2" | 30,4 mm1,3" | 33,02 mm1,4" | 35,56 mm
Display resolution (pixels)240 x 240240 x 240260 x 260240 x 240260 x 260280 x 280
Lens materialGorilla laminated glass with anti-fingerprint coatingGorilla Glass 3Gorilla Glass 3Gorilla Glass 3 | SaphirGorilla Glass 3 | SaphirGorilla Glass 3 | Saphir
MaterialsExtremely robust stainless steel housing, glass fiber reinforced polymer back coverBezel: stainless steel
Housing: Fiber reinforced polymer with metal housing at the back
Bezel: stainless steel
Housing: Fiber reinforced polymer with metal housing at the back
Bezel: stainless steel
Housing: Fiber reinforced polymer with metal housing at the back
Bezel: stainless steel, titanium or titanium with DLC coating
Case: stainless steel, titanium or titanium with DLC coating
Bezel: stainless steel, titanium or titanium with DLC coating
Case: stainless steel, titanium or titanium with DLC coating
Waterproof (meter)WR100 (100m)10 ATM (100 m)10 ATM (100 m)10 ATM (100 m)10 ATM (100 m)10 ATM (100 m)
WristbandsExchangeable (Quick Release/ without tools)Exchangeable (Quick Release/ without tools)Exchangeable (Quick Release/ without tools)Exchangeable (Quick Release/ without tools)Exchangeable (Quick Release/ without tools)Exchangeable (Quick Release/ without tools)
Integrated heart rate monitorYesYesYesYesYesYes
Integrated heart rate monitor under waterYesYesYesYesYesYes
Battery life
  • Smartwatch up to
  • GPS
  • GPS + Music
  • Max Battery GPS Mode
  • GPS expedition mode
  • Battery saving mode

  • 7d
  • 40h
  • -
  • 100h
  • -
  • -
  • 9d
  • 25h
  • -
  • 50h
  • 20d
  • 34d
  • 14d
  • 36h
  • -
  • 72h
  • 28d
  • 48d
  • 9d
  • 25h
  • 6h
  • 50h
  • 20d
  • 34d
  • 14d
  • 36h
  • 10h
  • 72h
  • 28d
  • 48d
  • 21d
  • 60h
  • 15h
  • 120h
  • 46d
  • 80d
Power ManagerYesYesYesYesYesYes
Suitable as 24x7 activity tracker (steps, sleep, heart rate)YesYesYesYesYesYes
Puls OxNoYesYesYesYesYes
Max. Number of data fields466668
Suitable for runnersYesYesYesYesYesYes
Pace ProNoVia Garmin Connect AppVia Garmin Connect AppYesYesYes
Running Power on hand wristYesNoNoNoNoNo
Suitable for cyclistsYesYesYesYesYesYes
Suitable for swimmerYesYesYesYesYesYes
Pre-installed mapsNoNoNoYesYesYes
Turn-by-turn NavigationYes
(via App Komoot)
Full maps on the displayNoNoNoYesYesYes
Golf mapsNoNoNoYesYesYes
Ski mapsNoNoNoYesYesYes
ANT+ (for HR chest strap, Power Meter, speed/cadence sensors, etc.)NoYesYesYesYesYes
Bluetooth Smart (for HR-chest strap, Power Meter,speed/cadence sensors, etc.)YesYesYesYesYesYes
Respiration rateYesYesYesYesYesYes
Heart Rate VariabilityYesYesYesYesYesYes
Analysis of general fitness conditionYes
(Nightly Recharge)
(Body Battery)
(Body Battery)
(Body Battery)
(Body Battery)
(Body Battery)
Accident Notification AssistantNoYesYesYesYesYes
Extend functionality with appsNoYesYesYesYesYes
Smartphone NotificationsYesYesYesYesYesYes
Smartphone Notification in sports modeNoYesYesYesYesYes
Weather display and forecastYesYesYesYesYesYes
Control of the music player of the smartphoneNoYesYesYesYesYes
Integrated music storage + pairing of Bluetooth headphonesNoNoNoYesYesYes
Musik Apps (Spotify, Amazon)NoNoNoYesYesYes
Internal memoryn/a64 MB64 MB32 GB32 GB32 GB
Smartphone AppYesYesYesYesYesYes
Desktop AppYesYesYesYesYesYes
ModelGrit XFenix 6SFenix 6Fenix 6S ProFenix 6 ProFenix 6X Pro
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