Product Comparison: Garmin Forerunner 15 vs Polar M400

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General Specifications
About the Product
Run with all your heart. Forerunner 15 captures essential stats from your run like time, distance and pace. When paired with a heart rate strap¹, it also records your heart rate and heart rate zone so you'll know when you hit your target.
Developed for runners who want a comfortable and durable running watch with sporty design and advanced GPS and training features. Track and record running as well as your other exercise, and monitor your performance accurately. Connect with the Polar Flow mobile app and stay active and motivated.
Forerunner 15
Key Specs
Display Type
Monochrome LCD
Monochrome LCD
Display Size
0.98" x 0.94" (55 x 32 pixels)
0.94" x 0.94" (128 x 128 pixels)
Built-In GPS
Other Sensors
Optical heart rate monitor
What customers say about "Key Specs"
Garmin Forerunner 15 GPS Running Watch
  • The watch is easy to use (I did not have to help her learn to use it at all), and she says that the display is easy to read with all of the info she needs in a quick glance.
  • The display is easy to read and the buttons are easy to push.
  • It has a large display for time and distance that makes it easy to catch a quick glance.
  • Nice product, with on-line site to display map of running route, complete with elevation and pace.
  • If you are looking for a budget gps running watch then look no further. The reason I did not give it a full five-star rating is for two minor reasons.
Polar M400 GPS Smart Sports Watch
  • The GPS work perfectly & quickly & accurately 100% of the time but this device has a large, easy-to-understand, perfectly user-friendly display!!
  • Perfect GPS, very occurate, very stable!
  • I love that display, convinient size and good colors!
  • GPS is a little finicky at times, takes a while to lock into the signal and controls could be better.
  • I always have a GPS finding issues, so frustrated!
Size & Weight
2.25 in.
2.2 in.
1.79 in.
1.96 in.
0.62 in.
0.47 in.
1.5 oz.
1.7 oz.
Tracking Features
Time, Distance, Pace, Step counter, Auto goal, Calories burned
Pace, Distance
Vibration Alerts
Clock Features
Time/date, Alarm
Time/date, Alarm
7 activities
30 h training with GPS and heart rate depending on your language settings
What customers say about "Functionality"
Garmin Forerunner 15 GPS Running Watch
  • Main screen with display time and then across the bottom you can scroll through: Date/ month, steps, goal, miles, and calories
  • This is a functional runners watch that ticks most of the boxes.
  • Overall, it functions accurately and is a band-aid solution to my need for a watch with a longer battery life.
  • Great simple GPS watch for those who don't want/need a multi-function fitness tracker/smart watch. I had a FR10 for many years and loved it.
  • It provides basic watch functions such as time, date, and alarm. Also, the watch includes a step counter.
Polar M400 GPS Smart Sports Watch
  • It is pretty cool. It gives you all kinds of info with maps, graphs, and charts.
  • This device records a ton of data and displays all of that data on the screen for you, and it even has a daily diary right on the screen.
  • The best part may be that I can set two interval timers to count down and alarm in continuous cycles, so I don't have to keep stopping and starting them during my run.
  • Like everyone else, I find the beep alerts hard to hear and wish it would vibrate, but I'm glancing down often enough that it isn't much of a problem.
  • The thing that I don't like is that it doesn't vibrate and it's kind of hard to hear it beep when Im running.
USB / Bluetooth
USB / Bluetooth
Android, IOS
Android, IOS
Water rating - 5 ATM
Water rating - 5 ATM
Wristband Material
Battery Type
Rechargeable lithium-ion
Rechargeable 240 mAh lithium polymer
Battery Life
5 weeks in watch mode; 8 hours in training mode
Battery duration up to 8 hours of training time with GPS and optical heart rate. Daily training session, continuous heart rate tracking and notifications: 5 days No training sessions, no notifications, continuous heart rate tracking: 14 days
Garmin Connect™ compatible, Compatible with foot pod³ for recording distance indoors
Running Program, Running Index, Continuous Heart Rate, Smart Calories, Sleep Plus, Training Load, Recovery Status
What customers say about "Features"
Garmin Forerunner 15 GPS Running Watch
  • Water resistant up to 50 m ( took my kids to Soak city all day and showered in it- no problem)
  • It's stood up to accidentally being dropped in a sink filled with water.
  • On the plus side, it did survive one obstacle race with a fair amount of mud and water submersion.
  • Longer battery time-8 hours training on garmin 15 versus the 5 hours on the Garmin 10, but will go around 8 weeks in fitness tracker mode.
  • Battery is rechargable but you have connect the cradle which is not always feasible.
Polar M400 GPS Smart Sports Watch
  • It has full support for the Mac computer, so you can plug it into your Mac, and it will sync to the Polar website.
  • Battery life is fantastic. I have never had trouble charging/syncing this watch.
  • I've been happy with battery life so far, it will generally last for a week of workouts no problem.
  • Battery life is pretty good, good purchase!
  • I have one complaint it's that the battery is only lasting 2-3 days.
Warranty / Certifications
Manufacturer Warranty
1 year(s)
2 year(s)
Other Information

Price History

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