Video made by Gauging Gadgets
Let's compare the Garmin Forerunner 245 and Forerunner 645. The Garmin Forerunner 245 is currently $300, with the music addition being $350. The 645 is $399 and the Music version is $450. Here we have $100 price difference between the 645 and the 245 Music with the 245 being even cheaper.
Both watches are protected by Gorilla Glass 3 making both very similar to the durability of the display. The most significant difference is going to be the stainless steel bezel on the 645. And then you actually have this black bezel which is made of a carbon fiber plastic but a very tough plastic at the first sight you might think it is metal.
The 645 is 1 millimeter thicker than the 245. There is no difference between the two when it comes to the watch bands, the same standard 20-millimeter watch band that came with them. You don't have the option of having a live heart rate on the 645 where you do have that on the 245. Both have the same resolution of 240 x 240. The heart rate data display right on the watch face 24 hours a day. The buttons look to be the same as well.
You can really see the difference on the back of the watches, there are the heart rate monitor and also the charging connector. So on the 245, you have the most up-to-date charging connector which is what is used on the fenix 5 the Instinct and the vivoactive 3. And you also have the newest heart rate monitor with the feature "pulse OX" which detects your blood oxygen level, the 645 does not have that feature.
Design difference: stainless steel bezel (645) vs. black bezel (245).
Garmin 645 has Garmin Pay which means you don't have to have your credit card, you can use the watch to make purchases at stores. The 245 is not compatible with Garmin Pay.
The Forerunner 645 supports Garmin Pay
The 245 allows determining your energy level through the day by using heart rate, sleep activity, etc.
If you want to store music, you have to buy the Music Edition of both watches, it allows storing up to 500 songs. They're both compatible with Spotify and beats all the different music apps that are available from Garmin. Regardless of which Edition you have, you still can control music storing on your phone.
Both support the same types of notifications and text responses. You can receive notifications from any app on your phone, with an Android phone, you can even respond to text messages using the watch. When you receive notifications, you can read the full text and even emojis are displayed. With the watches, you can reply to the messages.
The Garmin 245 has a newer cleaner look but in terms of settings, the watches are the same.
In terms of wifi, music, garment assistant, etc the watches are the same.
Activities and Tracking
Both have similar activities but the 645 has a lot more of the recreational activities. Both have basic workouts such as yoga, run/walk, bike, etc. The 245 has some activities that are not available in the 645 but the other way too. The 645 has HRV stress that measures the variations beat to beat with your heart. Those are not available on the 245.
Neither of these has hiking, but as an option, you can add activities, saying copy the walking activity and rename it into hiking. The 645 has an average speed which is not available on the 245.
When it comes to the elevation fields on the 245 the only option you have is just to show the elevation. But on the 645 you have tons of options in the elevation area. Like the 645 having a compass that is not available on the 245.
The 645 also includes muscle oxygen fields these do not look to be available on the 245 which is interesting. And then finally other fields which is going to be like battery and things like that sunrise sunset those are exactly the same on the two watches. Looking at alerts you have the ability for custom alerts you can have heart rate alerts, run-walk, pace, time, distance, cadence, calories.
The Garmin 645 has a thermometer, a barometric altimeter, and a gyroscope. Not available one the 245.
On SmartWatch mode, they are similar. When using it with daily activity, receive notifications, and stuff like that you will get 7 days for both. With GPS on, the 245 has a 24-hours battery life, where the 645 has 14-hours. With the Forerunner 245, you get an additional 10 hours.
Garmin Forerunner 245 lasts 10 hours longer with GPS on
Both of these watches are very similar with only some differences in the metrics. And then sensors that are available on them looks and size are also very sim with the biggest difference being the stainless steel bezel on these 645.