It’s called “Strava” and I used it today to track how fast I was going outside today for my brisk walk
. I went at a 3.2 miles per hour speed for more than an hour. A brisk walk is considered to be at a pace 3 to 4.5 mph.
You dont need to be connected to the internet either for it to track your exercise.
I highly reccomend it to anyone who is curious to know how fast they walk outside.
I use the free version.