AmazFit Stratos vs Garmin Forerunner 645 vs Fenix 5 detailed comparison

AmazFit Stratos vs Garmin Forerunner 645 vs Fenix 5

The Amazfit Stratos is certainly a fitness watch that offers some great features and some decent fitness tracking, but how does it stand up to a long-standing brand like Garmin? So in this article, I will match up the Amazfit Stratos vs Garmin Forerunner 645 vs Fenix 5 in the ultimate fitness watch showdown.

After recently testing the Amazfit Stratos for the review I recently completed, I used the Fenix 5x has the benchmark. I had a number of comments on the Active JR YouTube channel saying the Fenix 5x is a watch with some many in-depth features, that it was unfair to compare the Fenix 5x with the Amazfit Stratos. So whilst the Amazfit Stratos did well in the fitness tests, I thought it was only fair to do a comparison with a similar watch the Garmin Forerunner 645 music and included the Fenix 5

So why did I chose the FR645 and the Fenix 5 too compare with the Amazfit Stratos?

Garmin Forerunner 645 music: I choose the Forerunner 645 music to compare with the Amazfit Stratos simply because they offer similar features and specs. Both devices have music support built in and offer similar fitness features.

Read the Review

Garmin Fenix 5: I choose to include the Garmin Fenix 5x simply because the Garmin wearable is a very capable fitness watch and offers Firstbeat fitness technology. Whilst the Fenix 5x is a huge price increase on the Amazfit Stratos, I think it is important to compare how a budget-priced fitness watch like the Stratos can compete against it. 

Read the Review

AmazFit Stratos vs Garmin Forerunner 645 vs Fenix 5 review video

AmazFit Stratos vs Garmin Forerunner 645 vs Fenix 5 deals

AmazFit Stratos deals

Garmin Forerunner 645 music deals

Garmin Fenix 5 deals

AmazFit Stratos vs Garmin Forerunner 645 vs Fenix 5 design

When it comes to the design of each of the fitness wearables, they look pretty much the same, but each have different materials used in the build along with slightly different screens.


Amazfit Stratos

Garmin Forerunner 645

Garmin Fenix 5


45.72 x 45.72 x 12.7mm

42.5 x 42.5 x 13.5 mm

47 x 47 x 15.5 mm


70 g

42.2 g

87 g

Case material

Glass-reinforced Polycarbonate

fiber-reinforced polymer

fiber-reinforced polymer with stainless steel rear cover


Ceramic bezel

Stainless steel

Stainless steel

Screen size





320 x 300 pixels

240 x 240 pixels

240 x 240 pixels

Screen material

Corning® Gorilla® Glass 3

Corning® Gorilla® Glass 3

Sapphire crystal





Strap material

Silicon (Third party available)

Silicon (Third party available)

Silicon (Third party available)

Removable strap

Yes, Quick release

Yes, Quick release

Yes, QuickFit

Strap size


20 mm


Button material

Stainless steel

Stainless steel

Stainless steel

So as you can see the key differences between the Amazfit Stratos vs Garmin forerunner and Fenix 5 in terms of materials used in the design and the screen, but let me take a view moments to give you my take on the important aspects of the design and buildAmazfit Stratos vs Garmin forerunner 645 vs fenix 5 side view

Screen is important

The screen on a wrist-based wearable is important and you need to consider this when comparing the Amazfit Stratos vs Forerunner 645 vs Fenix 5. The screen material used on the Amazfit Stratos and the Garmin Forerunner 645 music is Corning® Gorilla® Glass 3 and on the Garmin Fenix 5 its Sapphire crystal. Whilst Corning® Gorilla® Glass 3 is strong and is scratch resistant, it will scratch if enough force is applied, whereas the Sapphire crystal display on the Fenix 5, it will take a lot of abuse. So when you choosing between the various fitness watches, consider what activities you are going to be performing and how you expect the screen to get touched.Amazfit Stratos vs Garmin forerunner 645 vs fenix 5 design

The other important thing to consider when it comes to touchscreens is the touchscreen aspect. The Amazfit Stratos is touchscreen, whereas the Fenix 5 and Forerunner 645 are not. My personal choice is not to have a touchscreen due to the fact when the screen gets wet, most are not very responsive

The last point on wearable screens is resolution and clarity. You are in luck with all 3 fitness watches as they all offer more or less the same specification screen with the Fenix 5 and the Forerunner 645 offering a 1.2’ 240 x 240 pixel screen and the Amazfit Stratos offering a 1.3” 320×320 pixel screen. Based on my testing all perform very well in sunlight and when you are performing an activity.

AmazFit Stratos vs Garmin Forerunner 645 vs Fenix 5x design verdict

In the design area, I think the Garmin Fenix 5 slightly pips the post on this one, the main reason is the sapphire crystal screen used to offer greater protection for the screen and the QuickFit bands that are easier to fit. However that being said, it does come down to personal choice on the design of each one and the Amazfit Stratos is a very close second in terms of design and looks.

AmazFit Stratos vs Garmin Forerunner 645 vs Fenix 5 activity tracking

All 3 fitness wearables come with activity tracking that will help you track steps, calories, heart rate, distance. However, all 3 don’t offer the same level of activity tracking or accuracy based on my testing of all 3 wearables.

Starting with the Amazfit Stratos which supports

  • Steps
  • Calories Burned
  • Heart rate, resting, average, max
  • Sleep tracking
  • Move reminders

During my testing of the Amazfit Stratos, the calories and normal heart rate tracking were accurate enough. However, the step tracking was often out when comparing it the Fenix 5 and the forerunner 645.

I also found the sleep tracking was not accurate with it giving incorrect sleep start and end times and numerous occasions. However that being said, I also take the relevance of the sleep tracking data on any fitness wearable with a pinch of salt.Amazfit Stratos step tracking

The Amazfit Stratos also features move reminders you get in most fitness trackers now, however it does not alert you if you have cleared the move target, unlike Garmin devices.

Moving onto the Forerunner 645 music and Fenix 5 as they both offer the same activity tracking features

  • Steps
  • Calories Burned
  • Floors climbed
  • Distance travelled
  • Heart rate, resting, average, max
  • Sleep tracking
  • Move reminders
  • Intensity minutes
  • Move IQ
  • Stress tracking

As you can see from the list above the Forerunner 645 has a lot more activity tracking built in and based on my extension testing most of them are accurate when comparing the FR645 to other activity trackers.

Just touching on a couple of key call outs, the first being MoveIQ. MoveIQ is built in activity tracking to automatically detect if you are performing an activity such as running, cycling or walking and records it automatically for you. The 2nd point to call out is stress tracking. Thactivityity tracking feature tracks your all-day stress and gives you useful feedback. I have found this to be useful both in testing and when I have been wearing the Fenix 5X as my everyday wearable.

AmazFit Stratos vs Garmin Forerunner 645 vs Fenix 5 activity tracking verdict

Both the Garmin Fenix 5 and the Forerunner 645 take the first place in this area. Both fitness watches have the same capability and based on testing work really well. The Amazfit Stratos has some basic activity tracking, but the step and sleep tracking let it down and it does not have the same depth of activity tracking as the Garmin wearables.

AmazFit Stratos vs Garmin Forerunner 645 vs Fenix 5 fitness features

A fitness wearable would not be complete without fitness features and tracking and all 3 used in this Amazfit Stratos vs Garmin Forerunner 645 vs Fenix 5 comparison, feature impressive fitness features.

Amazfit Stratos fitness features

The Amazfit Stratos supports, running, walking, cycling, swimming, triathlon, elliptical machine, mountaineering, trail running, triathlon, tennis, soccer and skiing. In my view this is a great start for a fitness watch at this price point and based on my testing it does swimming, cycling and running really well.

The Stratos also features an Optical heart rate sensors and for activities like running it works really well. For activities like cycling or sports involving the wrist, the optical heart HR sensor does not perform that well, but that is the same with most including the Forerunner 645 and the Fenix 5.Amazfit Stratos vs Garmin forerunner 645 vs fenix 5 HR

You also get FirstBeat technology built into the Amazfit Stratos, which up until now was only featured in high-end fitness GPS watches from the likes of Garmin with the FR645 and the Fenix 5 series.

FirstBeat brings a wealth of detailed performance metrics to the watch including maximum oxygen consumption (VO2max), Recovery Time Advisor and Training Load. You’ll also get your Real-Time Performance Condition for running, a very useful metric 

Limitations of the Amazfit Stratos for fitness workouts

  • The Stratos supports workout data fields, but these cannot be edited like you can on a Garmin
  • Workouts like running or cycling do not have auto pause, so you have to remember to pause a workout, you can do this on a Garmin
  • You cannot view the stats on the device when you have paused a workout. So not useful when you are resting on a ride and want to view average speed ect. You can do this on a Garmin
  • Surprisingly the Stratos does not feature a gym workout mode

Garmin Forerunner 645 & Fenix 5 fitness features

When it comes to the Garmin devices, like the activity tracking the fitness tracking features are pretty similar. Both Garmin wearables feature a load of fitness profiles from running, swimming, cycling and many many others.Garmin Fenix 5 vs Amazfit Stratos firstbeat

The Forerunner 645 and the Fenix 5 also feature gym workout profiles along with strength tracking that tracks how many reps you have performed during a workout. I personally cannot see why the Amazfit Stratos cannot track reps as it has the hardware, but the software would need to be updated.Garmin Fenix 5 training status

Just like the Stratos, the Forerunner 645 and the Fenix 5 feature FirstBeat technology and both of them offer pretty much the same features as the Amazfit Stratos and both work really well.

Key differences between the Fenix 5 vs the Forerunner 645 fitness features

  • The forerunner 645 does not support power meters
  • Whilst the forerunner 645 supports training load and status, it does not include workouts with no HR data. So swimming would not be included
  • The Forerunner 645 does not support Garmin HR Tri or Garmin HR run for advanced data, you can still connect them, but you would get advanced data from them
  • The Forerunner 645 does not have an open water swimming mode nor does it support triathlons
MUST READ  Amazfit Stratos bluetooth pairing process

Strava integration

All 3 feature the ability to upload your workout to Strava once you have completed it, however, the Forerunner 645 and the Fenix 5 feature Garmin live segments right on the watch to give you a real-time view of how you performing on that segment.


Each of the fitness wearables features various sensors to aid activity and connect to third-party sensors and the table below gives you a breakdown:

SensorAmazfit StratosForerunner 645Fenix 5
Wrist-based HRYesYesYes
Barometric AltimeterYesYesYes

Amazfit Stratos only supports Bluetooth heart rate sensors and Bluetooth headphones at this time. No other external Bluetooth sensors are supported you can see from the list above that more or less each fitness watch features a lot of the same sensors, however, a few call outs are needed.

  • Whilst the Forerunner 645 supports ANT+, it does not support power meters or the advanced data in the Garmin HR TRI.
  • The Amazfit Stratos does not support ANT+

AmazFit Stratos vs Garmin Forerunner 645 vs Fenix 5x fitness tracking verdict

Both Garmin devices earn the top spot for the fitness features, but if I really had the call it I would say the Fenix 5 just edges ahead due to the support for power meters and advance data from Garmin HR tri. However please in mind that the Amazfit Stratos performed equal to the Garmin devices in the tests for the areas it did support, so if you don’t need all the features of the Garmin devices the Stratos is a great choice.

MUST READ  Google Pixel smartwatch release date, features, what we know so far?

AmazFit Stratos vs Garmin Forerunner 645 vs Fenix 5 companion apps

Companion apps with any fitness watch are just as important as the device itself and this is down to the fact that most people want to look at the data post workout and analyze it and it all depends on the levels you want to go to in this regard.

Amazfit Stratos companion app

The app’s default screen is an overview of the day’s activity. Tapping on pretty much any metric will take you through to a more detailed overview. Along the bottom are tabs that allow you to cycle between activity stats, sports and profile. Depending on which of these you choose, you can view your daily summary.Amazfit Stratos english software

The Amazfit Stratos companion app based on my testing offers everything that the average user would want and it gives you data like a map, pace, speed, elevation and numerous other data points depending on the workout performed. You also get graphs of a number of data points within the workout

The Amazfit Stratos also has Firstbeat built into the device software which gives you data like Vo2 max, although this is only for running and training state which tells what condition you are in based on recent workouts. 

Overall the Amazfit Stratos companion app will be ok for most users, it does need a lot more work to give it polish around the edges and to put it into the same league as Garmin connect.

Garmin Connect for Forerunner 645 and Fenix 5

When I started writing this article, I already knew based on my testing that the Garmin Connect mobile app and the Garmin Connect web app was going to win this category and this is down to the depth of the app and this is the result of years of development.

Must read guide: Connect IQ store

Due to the extensive nature of Garmin Connect, I don’t have enough time to go into detail about the app and all the features, but unlike the Stratos app, Garmin has put fitness data front and centre of the app. The options to edit the device like changing watch faces or customisation options are hidden in sub-menus and the user experience is all about getting to the data and understanding what it means.Garmin Connect Mobile

Garmin has also included a web app that you can log into to access your data and its within this app you can create training plans and download plans that Garmin has already created. You can also export data to perform analysis in apps like Golden Cheetah or carry out analysis of the data right in the app itself.

AmazFit Stratos vs Garmin Forerunner 645 vs Fenix 5 companion apps verdict

It is no surprise the. Garmin Connect app is the winner here and that is down to the years of development and resources available to Garmin. Don’t get me wrong the Amazfit Stratos app does a good job and is good enough for most users, but those wanting advanced features would prefer the Garmin Connect app

AmazFit Stratos vs Garmin Forerunner 645 vs Fenix 5 smart features

No fitness smartwatch these days come with smartwatch features and the Garmin Forerunner 645, Fenix 5 and the Amazfit Stratos are no exceptions. All 3 wearables offer text, call, email, calendar alerts right on the wrist, however, none of them allows you to reply to them. in addition to the smart alerts, all 3 wearables also feature weather summaries.

Based on my testing all 3 fitness watches worked well when it came to smart notifications, but as I have said in previous articles I am not a massive fan of these features and often have them turned off unless I am looking at these features for the review of a watch

Amazfit Stratos vs Forerunner 645 music differences

First off, the Fenix 5 does not support music and it never will and I talk more why in this article. But luckily you do have a music option with the Forerunner 645 and the Amazfit Stratos, but they both offer different capabilities when it comes to music support.Amazfit Stratos vs Garmin forerunner 645 music

  • The Amazfit Stratos and the Forerunner 645 only support music that is DRM free. In short, this is not music that is protected from services like iTunes ect.
  • You cannot stream music with the Amazfit Stratos, but you can stream music with the Forerunner 645 from Deezer and iHeartRadio.
  • You can pair Bluetooth earphones with both the Forerunner 645 and the Amazfit Stratos

Wearable payments

Out of the 3 fitness wearables, the Forerunner 645 is the only one that supports payments via Garmin Pay. I have not had a chance to test this feature out due to yet to be launched in the UK

AmazFit Stratos vs Garmin Forerunner 645 vs Fenix 5 smart features

The bottom line on this one is that the Forerunner 645 along with the Amazfit take the led here and this is down to the music support on both wearables. All 3 fitness watches feature the same smart notifications. What you need to decide is if you want streaming or the ability to load music from a computer.

AmazFit Stratos vs Garmin Forerunner 645 vs Fenix 5 battery life

When it comes to a fitness watch, battery life is a just as important as its fitness features and all 3 offer varying levels of battery life.Amazfit Stratos vs Garmin forerunner 645 vs fenix 5

Amazfit Stratos battery life

  • Battery life: 5 days regular use
  • 11 days basic use

The Amazfit Stratos has got an ok battery life in real-world testing. The battery was lasting about 3 days with a reasonable amount of GPS usage.

Garmin Forerunner 645 music battery life

  • Smartwatch Mode: Up to 7 days
  • GPS mode without music: Up to 14 hours
  • GPS mode with music: Up to 5 hours

The battery on the Forerunner 645 was lasting about 5 days during my testing, but it would dip under than with music playback

Garmin Fenix 5 battery life

  • Up to 14 days in smartwatch mode (depending on settings)
  • Up to 24 hours in GPS mode
  • Up to 60 hours in UltraTrac battery saver mode

I have used the Fenix 5x has my daily watch and I get about 8 days of battery and that is with a mixture of sports tracking both GPS on and off.

Why buy the Amazfit Stratos over a Garmin?

You should buy the Amazfit Stratos over a Garmin if you are looking for a budget fitness watch that offers some comparable features. The Stratos is pretty much inline with accuracy when it comes to fitness tracking and offers triathlon support. However, take note that the companion app is not as good as Garmin Connect Mobile for features and data analysis.

Why buy a Garmin Forerunner 645 over an Amazfit Stratos?

The Forerunner 645 music is more expensive than the Amazfit Stratos offering similar features, however, Forerunner 645 offers more fitness profiles including strength and gym workout profiles and ANT+ which the Stratos does not. The FR645 also has Garmin support if anything goes wrong along with the powerful Garmin Connect Mobile app.

Why buy a Garmin Fenix 5 over the rest?

Whilst the Amazfit Stratos and the Forerunner 645 music will be adequate for most fitness people. The Garmin Fenix 5 is a step above with ANT+ and support for power meters and more sensors that both the others don’t support. The Fenix 5 also supports loads of sports profiles including open water swimming and gym workouts. The bottom line with the Fenix 5 is that its a watch that most people will never outgrow in terms of feature set and with most people not using it to its full.

Last word

As I say with all my articles and videos when it comes to buying advice, you need to buy based on what you think is right for you. Hopefully, this buyers guide between the AmazFit Stratos vs Garmin Forerunner 645 vs Fenix 5 has helped you, if it has please share it and if you have a comment or question, please leave it below

If you want to subscribe to our mailing list for the latest from Active JR

  • 1

Support Active JR

black Friday deals


  1. Stratos has floor counter feature that’s hidden in one of its basic watch faces and you can see it in the application. Also it has auto pause option during work out under the menu setting and yes the odd position of this feature is again due to software. Surely, it has compass. The last thing is that are you sure of the dimensions of stratos? I have the feeling that it is bigger than 45 mm.

  2. Hi, thanks for this interesting and very useful comparison. I have a Fenix 3HR and generally I am still very happy with this watch. But what bothers me a bit is that under low light conditions (indoors) I find that incoming notifications are very hard to read. Certainly reading glasses would help, but not very convenient while exercising… Fenix 5 seems to display the text in a bold font, which is better. But I don’t think this only would justify the upgrade. The Amazfit Stratos is a lot more budget friendly. How does the Amazfit Stratos screen perform indoors in your opinion? How are notifications displayed? Is it possible to change the font? Could you upload/send some pictures please? Thank you very much!!!

Leave a comment or ask a question

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Jon Ratcliffe
I have a huge passion for technology having worked in the sector for over 18 years in a variety of roles. I cover Wearables, tech and smart home. My reviews and information will talk about how the product works in reality and not just what the marketing departments want you to think.

Subscribe to Active JR social Channels


Latest Reviews