Garmin 645 vs Fenix 5 Comparison and Review

Smartwatches have always been a revolutionary product. Not only can you use a smartwatch to track time but it comes with features that allow you to keep track of important stats like the amount of calories that you’ve burnt, your pace, heart rate, and so on. That’s why today we’re reviewing two of the best smartwatches on the market; the Garmin 645 vs Fenix 5.

A sports watch is ideal for athletes or anyone who wants to stay active and fit through physical activity. Aside from well-known smart watch brands like Fitbit and Apple, Garmin is considered the crème de la crème of the industry and a pioneer in this field.

Garmin 645 vs Fenix 5 Reviews

So, Garmin 645 vs Fenix 5; which option is best for you? Well, that largely depends on your needs but we can say with confidence that we’ve chosen these two smartwatches because they are two of the best.

So, either way, you’ll be satisfied with your choice knowing that you’ve made an informed decision.

1. Garmin Fenix 5 Review

First up we have the Fenix 5, another fine specimen from Garmin. This stylish watch is suitable for everyday wear and yet it’s useful in a wide variety of training applications from paddle sports to golfing, skiing, swimming, cycling, and running.

It provides the wearer with smart notifications to let you know what your important stats are when it comes to the particular sports activity that you’re engaged in. This includes longitudinal ratio and oscillations, speed, distance, stride length, lactate levels, and VO2 max.

The data makes it that much easier for you to keep track of your performance and progress. Plus, you don’t need a chest strap to go along with this watch in order to benefit from its heart rate tracking features.

In addition to all the notifications mentioned above, this smartwatch will also keep track of your calories and sleep patterns as these variables affect your physical capabilities. It’s worth noting though that all of these features come at a price, as this watch is on the heavier side, weighing in at 2.4 ounces with dimensions of 0.6 by 1.9 by 1.9 inches.

The Fenix uses Bluetooth technology to connect to other devices which you can then use to track and read all of the data recorded by your phone in real time. Alternatively, you could opt for the Sapphire version of the Fenix 5 which comes with internet connectivity so that you may connect to the IQ store as well.

  • The display is easy to read even in direct sunlight
  • Waterproof for up to 10 atmospheres
  • Comes with changeable wristbands
  • You can customize its various features via the IQ store
  • Comes with advanced data that enables you to track your progress
  • It’s suitable for a wide variety of sports activities
  • It doesn’t have a music playback feature
  • You have to purchase the Sapphire version to enjoy Internet connectivity

2. Garmin Forerunner 645 Music Review

Next in our Garmin 645 vs Fenix 5 comparison, we’re going to review the Garmin Forerunner 645. It’s known as a multi-sports watch because it comes with the requisite features that you need to ensure superb performance.

It’s suitable for use in indoor and outdoor physical activities including cycling, running, hiking, and swimming. If you know how to use this smartwatch then it can provide you with all the data that you need to improve your performance.

This includes counting the number of steps that you’ve taken, your heart rate levels throughout the day, longitudinal oscillation and ratio, the amount of calories burnt, and ground contact time. You can also switch between different modes to get more customized updates such as strokes and speed which are unique to swimming mode.

The great thing about this smartwatch is that it’s Wi-Fi enabled and has the capacity to store up to 500 songs at once which means that you can listen to music and podcasts both on and offline.

This is in addition to the contactless payment feature which means that you don’t have to burden yourself with a wallet and your phone when going out. Simply press one button and purchase anything you want.

  • It comes with a convenient contactless payment feature
  • You can use it to play music on and offline
  • It can store up to 500 songs
  • It’s WiFi-enabled
  • Apps are available from the Garmin IQ store, which you can use to customize the smartwatch
  • Offers different modes for activities like strength training, running, cycling, and swimming
  • Designed to help you improve by providing you with advanced data
  • It’s pricey

Garmin Forerunner 645 and Fenix 5: Where Do They Differ?

Well, now you get the gist of what the Garmin 645 vs Fenix 5 have to offer. Now, it’s time to highlight the main differences between these watches so that it’s easier to make that final decision.


You may have noticed going through this Garmin 645 vs Fenix 5 comparison review that the Fenix 5 is weightier than the lightweight Garmin 645.

So, it’s obvious which one is more comfortable to wear on those long rides.

Sport Activities

There are many sports activities that you can track with the Garmin 645, from swimming to strength training, running, and cycling. The best part is that you don’t need a chest trap to collect any of this data.

However, if you really want to make the most out of this watch, then you’ll need to add the chest strap.

The Fenix 5 offers way more functionality. It comes with the ability to track more sports such as running, golfing, swimming, skiing, and even paddle sports!

It’s a great watch to have for anyone that wants to improve their performance and it offers superior data collection capabilities.

The Fenix is also hardier and can handle more water pressure compared to the Garmin 645.


Although both watches are powered by the same CR2 battery, one lasts longer than the other. Basically, if you choose the Garmin 645 then expect it to last up to 7 days.

The Fenix 5 battery can last for up to 14 days in smartwatch mode while setting it to GPS mode yields an impressive 24 hours. This is perhaps because the Fenix 5 doesn’t have a music playing feature so that’s why its battery lasts longer.

Either way, you want to ensure that your smartwatch has a long battery life before you use it on outdoor activities. In most cases you won’t have access to charging stations so it must be able to survive for long periods of time.


So, you’ve come to the end of our Garmin 645 vs Fenix 5 comparison. Which one did you like best? If you were to ask us for advice, we would recommend the Fenix 5.

Variety is the spice of life and if the ability to track more activity and collect more data is important to you then you should definitely opt for the Fenix 5.

It doesn’t need a chest strap, it comes with all the features you want and none that you don’t need, and it has a long-lasting battery. What more could you ask for?

Shailen Vandeyar

A proud Indian origin Kiwi who loves to plant trees and play with my pet bunny when not out doing about every kind of biking and experiencing the occasional tumble. Ready to share the ride with you.

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