The biggest difference between the Fitbit Surge and Fitbit Blaze is that the Surge has built in GPS, while the Blaze can use your phone's GPS. To answer some common questions, here are the facts.
1. Both trackers use the same PurePulse™ Heart Rate Technology. - Continuous, automatic heart rate tracking right on your wrist—only from Fitbit.
2. Both have exercise shortcuts for: Walk, Run, Cycling, and Elliptical. What's important to keep in mind is that the Surge can use it's on-device GPS for Walk, Run, and Cycling; while the Fitbit Blaze depends on your phone's GPS to map out these workouts.
Some of the less apparent differences about the Blaze include:
-Call/text notifications and music control only require a single Bluetooth bond (Surge requires a separate bond for each).
-On-device FitStar workouts.
-The Blaze can control music volume.