Fitbit Charge 3Fitbit Inspire HR
Tech specs 
SizeDevice Dimensions: 18.3 mm x 11.8 mm x 38 mm (W x D x L)
One size (small and large bands included)
Device Dimensions: 16.2 mm x 12.6 mm x 37 mm (W x D x L)
Small band: Fits wrists 140 mm - 180 mm in circumference
Large band: Fits wrists 180 mm - 220 mm in circumference
MaterialBuilt of more lightweight material including an aerospace grade aluminum case and Corning Gorilla Glass 3 display. The housing and buckle are made of anodized aluminum.The housing is plastic. The classic band is made of a premium, comfortable silicone similar to that used in many sport watches, and the buckle is made of anodized aluminum.
ChargingUSBUSB
BatteryLithium-polymerLithium-polymer
Battery lifeup to 7 daysup to 5 days. Charge time (0-100%): Two hours.
Water-resistance5 ATMup to 50 metres (swim-proof) - 5 ATM
Weight29 grams20 grams
SensorOptical heart rate tracker, 3-axis accelerometer, altimeter, SpO2, vibration motor3-axis accelerometer, vibration motor, optical heart rate sensor
DisplayOLED full touchscreen, TFTGreyscale OLED Touchscreen
Screen size38 x 18.3mm37 x 16mm
ColorsMultipleComes in a number of different versions
OtherNFC (Special edition)
Connectivity: Bluetooth, WiFi
Charge 3 stores your stats and data for 7 days in between the times you sync your tracker.
- Saves 7 days of detailed motion data – minute by minute
- Saves daily totals for the last 30 days
Activity tracking 
StepsYesYes
DistanceYesYes
Calories burnedYesYes
ActivityYesYes
FloorsYes
SleepYesYes (light, deep, REM)
Heart rate24/7Yes (Stores heart rate data at 1 second intervals during exercise tracking and at 5 second intervals all other times)
Stress & recovery
UV exposure
Skin temperature
Galvanic skin response
Hydration level
Calorie intake
GPSConnected GPSConnected GPS
Running features
Swimming features
Other Guided breathing, Female Health TrackingVo2Max/Cardio Fitness Level, 15 goal-based exercise modes, as well as breathing exercises.
Non-fitness functions 
Smartphone notificationsYesCall, text and calendar notifications
On-board music storage
Connected payYes (special edition)
LTE
Links 
Affiliate link*Amazon | FitbitAmazon | Fitbit
Read moreReviewReview
*Disclosure: We are a professional review site that receives a small commission from sales of certain items, but the price is the same for you. See our affiliate disclosure page for more details.
**All tech specs and images on this page come from manufacturers. These may change over time as manufacturers sometimes update their devices. While we cannot guarantee absolute accuracy of information on this page, we promise to review this content regularly and do our best to bring you the most up-to-date information. To be absolutely sure of tech specs of a particular device, we recommend checking the manufacturer’s website.