The Garmin Fenix 47mm and 51mm are quite alike, with many of the same features, but there are a few notable differences that can influence your decision. In this article, I’ll break down these key distinctions, from price and battery life to design and variant models. We’ll dive into how both models feel on the wrist and perform during daily use, so you can get a clear picture of which one suits your needs best. Let’s get started.
Table of Contents
Garmin Fenix 8 47mm vs 51mm: Verdict
 Go for the Garmin Fenix 8 47mm if: – You prefer a more lightweight smartwatch. – You don’t want a thick bezel around your screen. – You’re not an ultramarathon runner and just need a smartwatch for casual use. – You want the more affordable option. |  Go for the Garmin Fenix 8 51mm if: – You need a more rugged design with thicker bezels. – You’re willing to invest more for 9 extra days of use (compared to the 47mm). – You’re an ultramarathoner. – You want 33 more hours of GPS battery life (compared to the 47mm model). |
If you’re looking at the Garmin Fenix 8 47mm and 51mm, you’re actually considering six models:
The Garmin Fenix 8 47mm comes in three variations:
- AMOLED glass/steel – $999
- AMOLED sapphire/titanium – $1,099
- Solar Sapphire/titanium – $1,099
Much like the 47mm, the Garmin Fenix 8 51mm model also offers the same variations:
- AMOLED glass/steel – $1,099
- AMOLED sapphire/titanium – $1,199
- Solar Sapphire/titanium – $1,199
The main differences between these models are the materials for the bezel and lens, along with the solar charging feature. The 51mm versions are priced a bit higher because of these premium upgrades.
To keep things simple, I’ve decided to stick with the base models—the AMOLED glass/steel versions—for our Garmin Fenix 8 47mm vs 51mm comparison.
When it comes to these two, there are only 3 key differences—price, design, and battery life. The rest of the features like heart rate monitoring and GPS accuracy are identical. But if we were to see which one is the overall better, let’s dive into where each model has the edge.
We’ll break down the 3 major differences between the Garmin Fenix 8 47mm vs 51mm in more detail in the next section.
Best Overall: Garmin Fenix 8 51mm
If I were to choose, I’d go with the 51mm model. The thicker bezel gives it a more rugged look, and it offers much better battery life than the 47mm, though it’s a bit pricier. But with those upgraded features, you won’t have any doubts about the extra cost.
Best Budget-Friendly: Garmin Fenix 8 47mm
If you’re looking to save some money and want a smartwatch that’s a bit more lightweight with a thinner bezel, the 47mm model is the way to go. It delivers excellent performance and comfort at a more affordable price, without sacrificing key features.
Best Battery Life: Garmin Fenix 8 51mm
For ultramarathon runners, longer battery life is a must. The 51mm model gives you up to 13 days in smartwatch mode, compared to the 47mm’s 7 days. In GPS mode, the 51mm lasts up to 84 hours with gesture and 65 hours with the always-on display, while the 47mm maxes out at 47 and 37 hours, respectively.
Best Design (Personal): Garmin Fenix 8 51mm
Personally, I’d go for the 51mm model because I like the rugged feel that adds to its character. That said, it’s not set in stone that the more rugged the design, the better the smartwatch. The 47mm model has a slimmer bezel and is lighter—perfect for users with small wrists. It’s the more comfortable option for daily wear and is easier to sleep with.
Best for Casual Use: Garmin Fenix 8 47mm
For everyday use, the 47mm model is my pick. It’s comfortable, easy to wear, and doesn’t feel too bulky.
Best for Ultramarathon Runners: Garmin Fenix 8 51mm
For ultramarathoners, the 51mm model is the clear choice. Its larger battery is perfect for super long runs.
3 Major Differences Between Garmin Fenix 8 47mm vs 51mm
Garmin Fenix 8 47mm vs 51mm: Battery Life
As you can see below, both the Garmin Fenix 47mm and 51mm offer eight modes, and your battery life largely depends on which one you use. The battery life numbers might seem all over the place at first, but they start to make sense once you focus on your specific use case—after all, you’re probably not going to use all eight modes.
Here’s what each of these modes is all about.
- Most users stick with the Smartwatch mode for daily wear since it offers a good balance of features and battery life.
- Battery Saver Watch Mode maximizes battery life by disabling non-essential features and lowering display usage. This mode’s ideal for long trips or when you’re low on battery.
- You can use the GPS Only mode for activities where you need basic GPS tracking (like running or hiking) without extra satellite features.
- All Satellite Systems Mode is preferred for more demanding activities in areas with weak GPS signals, such as dense forests or urban environments.
- All Satellite Systems Plus Multi-Band Mode Combines multiple satellites and multi-band technology for the highest accuracy, even in challenging environments.
- All Satellite Systems with Music Mode tracks activity with full satellite accuracy while playing music directly from the watch. It’s most popular for runners or gym-goers who want music without carrying a phone.
- Max Battery GPS Mode is great for ultramarathons, long hikes, or multi-day outdoor activities. You’ll need this mode when setting off on super long hikes and runs. It’ll optimize GPS tracking to extend battery life for long-distance adventures.
Garmin Fenix 8 47mm vs 51mm: Design
The design differences between the Garmin Fenix 8 51mm and the 47mm version are noticeable in a few key areas. The most obvious one is the size.
- Size: The larger model measures 51x51mm with a thickness of 15.4mm, while the smaller version comes in at 47x47mm and is slightly thinner. Although the official specs say there’s only about a 2mm difference in thickness, on the wrist, the smaller watch feels considerably thinner.
- Weight: The 47mm model is significantly lighter, with the steel version weighing 59g and the titanium model coming in at 52g. The 51mm version is heavier across the board, with the steel case weighing 74g and the titanium version at 64g. That’s just the case weight—once you factor in the strap, the larger model feels even bulkier on the wrist.
- The Feel: Another thing to keep in mind is how these watches feel based on wrist size. On skinny wrists, the 47mm watch is simply more comfortable. It feels lighter, less bulky, and is easier to wear for long periods. That said, you still can get used to the larger watch over time. If you’re set on the larger model but worried about comfort, my years of using smartwatches have taught me that swapping the silicone strap for a nylon band makes a noticeable difference. The nylon strap helps distribute the weight better—your watch will feel less like a heavy object on your wrist.
Garmin Fenix 8 47mm vs 51mm: Price
The 51mm Garmin Fenix 8 is $100 more than the 47mm Fenix 8, regardless of the model type (AMOLED, Solar, Steel, Sapphire, Titanium).
If you’re not specifically looking to save money, the 47mm model offers a better value:
- For the same price as a steel 51mm Fenix 8 with a glass screen, you can get a Sapphire Titanium 47mm version, which has a more durable and scratch-resistant sapphire crystal screen.
This means choosing the smaller watch could get you higher-end materials without spending extra.
3 Great Alternatives to Garmin Fenix 8 47m and 51mm
Aether X Limited Edition Designer Smartwatch
Link to Product: Aether-X
Price: Subscribe and leave a refundable deposit to reserve for just $255 (regularly $355).
The limited edition Aether X smartwatch is a luxury watch with a modern design and advanced health features. It has a metallic body, a genuine red patina leather strap, and a variety of health-tracking features, including 45 sports modes, sleep tracking, and stress management. Only 10,000 pieces will be available, and the watch comes with free shipping and up to 25% off.
Looking to discover more innovative products? Check out Prelaunch Marketplace for the latest projects and exclusive offers!
Garmin Instinct 3
Best for No-Frills GPS and Durability
Link to Product: Garmin Instinct 3
The Garmin Instinct 3 is a tough GPS smartwatch built for outdoor lovers, with a rugged design, long battery life, and solid health tracking. It comes in two sizes (45mm and 50mm) and offers either an AMOLED or Solar-powered display. Prices start at $399.99 for the Solar model and $449.99 for the AMOLED version. You can check it out and buy it on Garmin’s official website.
Samsung Galaxy Watch 6
Best for Samsung users
Link to Product: Samsung Galaxy Watch 6
Price: $299 for the 40mm version and $329 for the 43mm version
This one’s the top pick for Samsung users. It stands out with health tracking features like body composition analysis and snoring detection. Plus, with personalized workout tips and sleep coaching, it keeps you on track with your fitness goals. The large display and smart features make it a practical yet stylish everyday companion, and it works seamlessly with your Samsung devices.
Conclusion
Choosing the Garmin Fenix 8 47mm vs 51mm isn’t as hard as it seemed, right? It really comes down to what matters most to you in terms of design, battery life, and price. After all, their core features like heart rate monitoring and GPS tracking are identical, so you’re left with figuring out those three.
I’d personally go with the 51mm model since I love the rugged feel with a thick bezel and extended battery life. So if you’re on the same page, the 51mm is your top choice.
That said, if you want a smartwatch for casual use and won’t be running ultramarathons, the 47mm model would be a smart decision. It also feels and looks better on small wrists.
