2019 Garmin Forerunner 45, 245M, 945 and Fenix 6S Pro Comparative Buyers Guide and Reviews

Article by Sam Winebaum

Garmin Forerunner 45, Forerunner 245 Music, Forerunner 945, Fenix 6s Pro


Introduction
Garmin's 2019  Forerunner series  and Fenix 6 series watches  have much in common.

• In my extensive testing on road and trail, one on each wrist (well only two at a time as I only have two wrists!) I found the critical basics of GPS distance, pace, and wrist heart rate accuracy to be for all intents and purposes extremely close to identical for all the watches here. In fact Garmin, tells us they share the same sensors with the only differences being the GPS antenna configurations
• While the 45 has a lower resolution screen than the others, all the screens were highly legible in bright light conditions and are the most legible of any of the many recent watches (Suunto, Polar, and COROS) I have tested.

• All feature 5 button operation with the layout functioning in the same way on all watches.
• All are extremely light and easy on my small wrist ranging in weight from 36g to 58 g and are  close enough in physical dimensions to be at time difficult to tell apart off the wrist.
• All have music control to your phone and Garmin's new Incident Detection and other safety features such as Live Track,
• All make identical use for all features they share in the Garmin Connect app.

If you have an older GPS watch such as a Forerunner 10, 15, 35,  230/235 you will find:

• improved battery life specs and run time  and also as your older watch likely now holds less charge
• improved GPS and wrist HR accuracy as there are new sensing modules in these models
• new features such as Incident Detection on all watches, on watch music storage and play (234M, 945, 6 Pro), on watch topo and road mapping (945, Fenis 6 Pro) as well as Garmin Pay (945, 6)
• new sleep and stress tracking

Where they differ is in price, battery life, and run features.  I run, hike, and nordic ski so this article is in that context and I have extensive tested all of them over the last several months,  I did not test the cycling and swimming features,

I have "painfully" tabulated all the data fields and run feature options  on each watch in the table here and will detail key ones in the article.

Garmin Official Specs here


Read on for all the details but to cut to the chase.. We tested the following models and this is how they differ:

• Forerunner 45 ($200), RTR video review) if budget is key and you just need basic distance, pace, and heart rate but do still want smartwatch features such as phone notifications, music control, sleep and step tracking. As the smallest and lightest ( and even available in a yet smaller lighter 32g 45S version) it is the best choice for very small wrists. (RTR Review)

• Forerunner 245 Music $350 ($300 w/o music)  if you need longer battery life and deeper training and physiology features along with the optional on the watch music capabilities including Spotify playlists.  With its breadcrumb navigation features, Pace Pro and now confirmed by testing 24 hour GPS/HR battery spec, it can function as a more than adequate trail and ultra watch. 

• Forerunner 945 ($600) if you need ultra worthy battery life, full multi-sport tri capabilities, deeper physiology and training effects features, along with what I have found very useful, especially off road, fully detailed maps with data overlays and turn indications. You also get Garmin's wallet less Garmin Pay and on board music including Spotify playlists. 

• Fenix 6S Pro ($700 and up) Update: Full in depth 6S review here. if you want all the features of the 945 in a more rugged case, more options to extend battery life, new Pace Pro (also to be an update to 945), ski area maps, a new highly informative default watch face and a new single screen summary of all daily info "Widget Glance"  of what is on the others here on multiple screens.  

Below each overview widget are detail screens. Additional widgets even Dog Track can be added.

Watch our YouTube on the Widget Glance and default watch face 

The Fenix line dramatically expands to 10 models in 3 sizes: 42mm(6S and 6S Pro)  47mm(6 and 6 Pro), and 51mm (6X Pro and Pro Solar) with option for each Pro of a Sapphire crystal, a solar powered version the 6X Pro Solar along with non Pro versions ($599) of the 6S and 6 but not the 6X. These non Pro versions do not include PacePro, Trendline Popularity and on board music  Confused yet?

Size/Weight Shape/Screen
The bottom line here is that the 45, 245, and 6S watches all have a 42 mm diameter cases with the 945 having a 47 mm diameter.  You get a 47mm diameter case in the Fenix 6 Pro and Fenix 6 and a 51mm diameter in the 93 g massive Fenix 6x Pro with no non Pro Fenix 6x available. Case size comes down to preferences and how much presence on the wrist you seek but generally speaking  larger diameter thicker cases are less comfortable and produce less accurate wrist HR results the smaller your wrist is.  I prefer the size, shape and weight of the 945 best with the 245 a close second but a bit on the small size and lacking in presence on even my relatively thin 6.5" wrist.

In the photo above the identical diameter Forerunner 45 (top) and Fenix 6S (bottom). After size all that separates them is more battery life, features, maps, and a $500 difference in cost

All 4 watches are relatively light and weight affects comfort and accuracy when combined with case size. 

The 45 weighs a minuscule 36 grams with a yet smaller diameter 45S version coming in at 32 g. 

The 245M weighs a mere 2.5 grams more yet has far superior battery life and features in the same diameter case.

The 945 comes in at a remarkable 50 grams with the 6S and its smaller than the 945's 42mm diameter metal case only adding 9 more grams to 59 grams. All are light enough and small enough to produce solid wrist heart rate results for me. 

The watches we tested all have a 1.2" / 30.4mm diameter screens with a 240mm x 240mm resolution, including the larger case diameter 945. The exception is the 45 which has a 1.04" / 26.3 mm diameter screen with 208mm x 208mm resolution. In my testing in all kinds of light conditions there was no appreciable difference in legibility and the slightly lower resolution of the 45, while visible, is not really a functional issue as the 45 does not have the topo or breadcrumb navigation of the others where higher resolution is useful,

Left to Right: Forerunner 45, 245M, 945, Fenix 6S

Case thicknesses differ.  The 45 comes in at a very slender 11.4mm, the 245M at 12.2mm, the 945 at 13.7mm and the 6S at 13.8mm. Case thickness is essentially a function of battery life and memory and to an extent materials as the 6S has more metal in its case vs. the plastics of the others. I find the 245M has the best balance of thickness, weight, and strap design but prefer the slightly larger presence of the 945 on my wrist. The 6S was noticeably thicker feeling and less comfortable initially than the others due to its more rigid strap and its rigid swappable strap connection in the first part of the strap. Over time the strap has softened and comfort has improved.

Sensing
All four are said to have a new GPS sensor and it is possible the exact same sensor as they all perform nearly identically but given different cases have different GPS antenna designs .

Left to Right: Forerunner 45, 245M, 945, Fenix 6S

All four have a new rear sensing unit for heart rate and in the case of 245, 945, and 6S also a pulse oximeter sensor although the two LED lights and two sensors appear the same on all units.

Battery Life
I have done extensive testing of the battery life of all models. 

6S: I am seeing approx. 22 hours in GPS/HR mode so a bit under the spec of 25 hours.

945: I have seen 32-36 hours in GPS/HR mode so a touch under the spec 36 hours.

245: Early in my testing back in August I notified Garmin that I was seeing 17-18 hours in GPS/HR mode. As a result they identified an issue. With the latest November firmware update I can confidently say that it now meets the spec of 24 hours in best mode. 

45: There is no numerical battery gauge on the 45 so it difficult to totally accurately judge the spec of 13 hours but my testing indicates it is close to or at spec. 

The 945 and 6S allow you to set remaining battery % as a data field one hundreds. The comparative data field list for all watches can be found here.  

Further the new Power Mode in the 6S shows the estimated remaining battery for 3 modes. When I took the pictures below the percentage remaining was 90% as shown above as a data field.

Normal: GPS, wrist HR, music and notifications.
Max Battery: turning off music, heart rate, and phone connection
Jacket: cleverly leaving music and phone connection on and as while the watch is over clothing turning off wrist heart rate.
Expedition: Accessed as a activity, all sensors and phone connections are turned off with the watch going into a lower power mode. A GPS track point is recorded once per hour. The estimated battery life in this mode is up to 20 days. I did not test.

I have not found a way to further tune the Power Modes directly in the Power Mode interface but you can of course change other settings such as backlight, etc..

The 245 shows you remaining battery percentage when you enter the activity selection screen while the 45 shows battery as a graphic with no numerical indications.

Watch Faces

The 6S default watch face is very informative with the data elements around the outside configurable for a vast selection of data points.

Data Fields
I have "painfully" tabulated all the data fields and run feature options found/configured on each watch in the table here and will detail key ones in the article.

The 45 has a very basic and limited number of data fields as shown below. 

The 245 adds far more variety and options as far as data fields including Pace Pro, physiology features including Performance Condition and basic breadcrumb navigation. You could stop at the 245 for most all run purposes.

The 945 and 6S as they have more memory, greater processing power and battery life and let's just say "marketing differentiation" and thus prices follow add a barometric altimeter and deeper navigation features with three key sets of features to consider.

Pace Pro
Pace Pro is a new feature of the Fenix 6 Pro series (but not Fenix 6), the 245 and the 945. It is based on courses in Garmin Connect you have run, created, or searched out (for example race courses). You create a PacePro strategy based on either splits (mile or km) or course elevation changes. The feature will calculate your course split paces based on your selected overall pace and  the terrain, automatically and can also be tweaked for a positive/negative 1st and 2nd half of course  pacing strategy  and/ or harder or easier uphill efforts.

In the example above I selected change in elevation with my course broken into three segments by the software,

As you are following a course and the Fenix 6S and 945 provide turn by turn directions during my first slower uphill 3.16 mile split it indicated a turn ahead as seen above.

At the beginning of every new split you will get your new pace and the distance for the split

The split above started with a steep downhill where I was faster than split goal pace which was OK. With a bit of an uphill to follow I ended up closer to the 9:07 per mile split target.  Your distance completed on the split is indicated by the blue bar and your overall time ahead is indicated at the bottom.

The final slight downhill to flats final split I guess I had set my target to slow as I ended up almost 2 minutes ahead of the target. I found the elevation based Pace Pro here quite useful as I worried less about my slower pace on the first slight uphill 3 mile segment then took advantage of the downhills to flats, The same course based on mile splits is below.


If a course is loaded to your watch you can initiate a Pace Pro  strategy directly on the watch setting a pace goal. Below I set one up for a trail run in Park City. That third split is a stout uphill climb on the Rambler Trail and the fourth a long smooth downhill,
The picture below shows my progress on the 1st split.

Where Pace Pro can get interesting is for a hilly marathon course such as Boston's. Below I asked it for a bit of a positive split and an easier push on uphills with a 3:40 goal time. Note how fast it has me going out at the start. I might wish for an "easier" on downhill option but after that the pacing seems logical

ClimbPro
As with Pace Pro, Climb Pro is based on courses you load to the watches and is available on the 945 and 6S, The example below is for a hike in the White Mountains of New Hampshire with lots of flats and one very steep climb. Courses with multiple climbs would each have not only an overall view of the course but will alert and apprise you of your progress for each individual climb.

In the photo above the 945 is telling me that Ihave covered 557 of climbing with 2738 feet to go with maximum and minimum altitudes also shown. I must say knowing how much more to climb is super cool and can be motivating, or discouraging!  I was real happy when I took the picture below a little later that day! The totals don't quite add up as my loaded course wasn't exactly what we did,

In the example below at my local park I loaded my usual course and took the picture at the start of the first of three climbs with the 945 telling me the climb is 0.33 miles with 186 feet of climbing. On shorter climbs I generally ignore the vertical speed,

The Fenix 6S will show exactly the same Climb Pro screens as the 945. The 245 and 45 do not have Climb Pro.

Performance Condition
I find that Performance Condition metric one of the most useful features. It is included on the 245, 945, and 6S but not the 45. Here is how Garmin describes it.
"The Performance Condition metric is a real-time assessment of your ability to perform compared to your average fitness level. This metric ranges from -20 to +20 with each point representing approximately 1% of your VO2 Max. During the first 6-20 minutes of an activity the device will alert you to your current Performance Condition. This can also be used as an indicator of fatigue level, especially at the end of a long activity. Performance Condition is calculated using the following for running: Pace, Heart Rate, Heart Rate Variability"

Assuming I get a solid initial wrist heart rate, I often adjust the intensity of the rest of my run after the first 7 or so minutes when my day's Performance Condition appears on the screen after some vibrations to alert me. If I see a +4 or +5 I know I can push my workout. If I see a minus value I take it easier than planned. I have never seen values much above +5 or below -5 so question the ranges presented above but must say my VO2 max is 48 or so due to my age which likely affects the range.

I think this metric is extremely valuable especially for those following training programs as it can reign in what might be an excessive effort if that is what was planned for the day or encourage a harder one if the values are positive. See those minuses to many days in a row you know you are overtraining or over tired.

 

I did not capture a live picture as the PC metric does not appear for long but you can see what it would have shown and where my condition started and then went in the screen shot above of a recent 1:39:01 half marathon race below. 

With a +5 or so I knew I would have a decent race and did!

After the Run

GPS and Optical HR Accuracy
I have found hardly any significant differences between any of the four watches, after all they all share the same sensors with the differences in their antenna arrays and case size.

Graphs: DC Analyzer

Above a half marathon where I wore the 245M on my non dominant wrist and the 945 on my dominant wrist. It was cold, low 40's and I was in short sleeves so the early high heart rate wobble for the 245M in blue is not unexpected in such conditions on my thinner lower blood flow non dominant wrist but settled down after 7 or so minutes. Note also the slight difference in elevation gain above. The 245M relies on GPS for elevation, the 945 a barometric altimeter. 

45 vs 245 on Trail


Heart rate was remarkably close for both above and they both tracked the winding single track very well below

I did note a difference in distance clocked with the 45 registering about 200 meters more over the approximate 9.5 km course. I have found the 45 somewhat "optimistic" compared to the others on many runs but well within reasonable.

Pulse Oximeter
The 245, 945, and 6S all have a pulse oximeter which measures the percentage of oxygenated blood (SpO2 %).

This feature is most useful to determine your acclimation to high altitudes. Even at 6900 foot Park City I have found it of limited utility.  

Navigation and Maps
The 245, 945, and 6S all have course navigation and maps with the  945 and 6 full topo and road maps and the 245 breadcrumb lines. The 45 does not have any course navigation. The 945 not only has navigation but also topo, road, and in the 6S you get ski area maps on board, all built into the watch.  You do not need to be following a course to see your location on the maps. Maps can be included as a screen for any activity and are also accessible from the main standby screen. You can zoom in and pan on the maps. See our Garmin maps article, based on the Fenix 5 Plus, here

Red (at the bottom of the photo above) indicates where you have come from, purple where you are headed, "215ft" a heads up for a turn ahead. Turns off road are generally sharp turns in direction, I estimate more than 90 degrees.  If you go "off course" I have measured ( and the watch will indicate distance off course) that the watch will notify you within 60-70 feet of  an off course, On road using road maps instead of topo maps, where essentially Garmin has baked in their auto GPS navigation system, the turn will be an actual road junction decision notification.

You can overlay two data fields of your choice over the map and there are hundreds to choose from in the 945 and 6S. For this hike I picked average pace (miles per hour or speed would have been better) and elevation.

In the photo above the final destination of the course, the peak, is clearly called out, and seen, at 0.11 miles ahead

The level of up to date detail is quite stunning. Above we can see all the trails in a recently built mountain biking trail complex near Sugarloaf Maine, and even if you are not following a specific course as above at junctions you can call up the map and decide which way to go,

The 245 does not include maps but does have the ability to follow "breadcrumbs" along a course. Below a course I set up for a trail run in Park City via the Intensity Heat Maps in Garmin Connect which show the intensity of use of a given trail or road or segment of those. Click to connect segments building your course and send to your device.


You can pan and zoom including on the run but as there is no topo as above the view is quite sparse, say in comparison to the Maine mountain bike trail complex shown above. The area I ran the course with the 245 is also a big trail complex yet all we see is the green line to follow.  On the 945 and 6S every trail and junction on this course is indicated on the watch maps, way more informative and useful . As with its bigger siblings it will notify you of turns and of an off course and provide you an ETA to complete.

It turned out part of my chosen course was closed so I went "off course" indicated by the black line above 

There is a screen showing how far you are of course, direction to get on course (straight line it seems,,,) and distance remaining if you get back on course. I will also note that the Pace Pro strategy I was following essentially locked up once I went off course as the course was no longer relevant. I did not check what happened to Pace Pro after I rejoined the course more than 2 miles later and will update when I next try the course with Pace Pro, avoiding closed trails!

The 45 does not have any navigation features.

Garmin Connect App and Website
Once your activities are complete they are synched to Garmin Connect, and if you choose, and set up automatically send of to other sport services such as Strava. Synching was highly problematic for several weeks after an iOS update for all 4 watches but is now solid, if as always with Garmin sometimes unpredictable as to when the activity will actually synch.

Once over at the Connect app all of your activity, steps, sleep, heart rate, stress, Body Battery, and I am sure I am forgetting a lot will be viewable. You can go deep on every item. What Garmin is still not as strong as Polar and its Polar Flow app in doing is giving you a long term perspective of your training progress.

Below more of what I see for today as I write, including yesterday and a 7 day trend. Please realize the duplicated runs are side by side tests of the watches in this review. The data is remarkably close between the $350 Forerunner 245M and the $700 Fenix 6S Pro for today's 5.87 mile run with a match up of 945 and 6S yesterday having the 945 a bit more optimistic as to distance for that 3 mile trail run. This said, for the basics of distance and heart rate,  all of the watches in this article perform, and well, with very similar results regardless of price. If I had been running the $200 Forerunner 45 side by side with the $700 Fenix 6S you would see pretty much the same agreement between watches. 

Conclusions

Given that the basics of screen legibility, GPS tracking, wrist heart rate, and even weight and size are essentially very close from the $200 Forerunner 45 to the $700 plus Fenix 6 Pro decisions come down to budget and features.

If budget is paramount and you just need the very basics for training on the watch with most all the other smart watch features such as (steps, sleep, notifications, music control, etc..) then the Forerunner 45 is a great choice.

If you want longer battery life, basic navigation, many more data field choices and physiological insights then the $300 Forerunner 245 (without music) or the $350 Forerunner 245 Music. It is a great value for a fully featured training watch in a 38.5 gram package with outstanding 24 hour battery life.

If a slightly larger wrist presence, the longest battery life by close to 10 hours, on board mapping and turn by turn directions, full multi sport capabilities, music on board and contactless payments all in a light 50 g package then for sure the Forerunner 945 which for a limited time is $100 off at $500 at our partners below is the ultimate hard core sports watch.

Fenix 6S Pro

If you want a rugged premium Garmin in a small diameter size, available in many stylish colors beyond our basic black and also in other sizes  and with all the features of the 945 then the Fenix 6S Pro  or its larger siblings Fenix 6 and 6X Pro and even Solar or for a little less money but without the mapping, Pace Pro, or Widget Glance the Fenix 6. And for a limited time the last generation Fenix 5 Plus also with mapping but as far as know without the Widget Glance, the new default watch case, or Pace Pro and a slightly smaller display and overall shorter battery life is $150 off at our partners below

Comparative Watches

Forerunner 45 : Basics and budget

COROS Pace (RTR Review), Polar Ignite

Forerunner 245 : Value full featured multi sport

Polar Vantage M (RTR Review), Suunto 5 (RTR Review), COROS Apex (RTR Review),

Forerunner 945: Hard core multi sport 

Polar Vantage V (RTR Review)

Fenix 6 and Pro : Full featured, long battery life, premium materials 

Fenix 5 Plus (RTR Review), Suunto 9 Baro (RTR Review), COROS Apex Pro (RTR Review) and Vertix (RTR Review)

Read reviewers' full run bios here. 

The products reviewed were provided at no cost. The opinions herein are the authors'.

Comments and Questions Welcome Below!

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