Overview

  • All-day Stress Detection
    Recognize stressful events, manage them and move on with our new continuous EDA sensor on Fitbit Sense 2. It helps detect stress events so you can start to see how and when your stress is triggered. Use of the cEDA sensor may affect battery life.
  • Stress Management Score
    Get a handle on your stress. Higher score? You’re showing fewer signs of stress. Lower score? Time to find better balance–try a meditation or go for a walk.
  • Sleep Stages & Sleep Score
    Learn about the quality of your previous night’s sleep with a personalized Sleep Score. See a breakdown of time in light, deep & REM sleep to see what’s impacting your rest.
  • Google ECG App & Irregular Heart Rhythm Notifications
    There are two ways to uncover Afib, right at your fingertips. With the ECG app, you can take an assessment on demand. Plus, use irregular heart rhythm notifications to look for signs of Afib while you’re still or sleeping.³
  • High & Low Heart Rate Notifications
    Your heart rate is a key indicator of health, so Fitbit Sense 2 keeps you informed when it’s above or below your set resting threshold.
  • Daily Readiness Score
    Enhance your workout routine with a Daily Readiness score that reveals if you’re ready to push or should focus on recovery.
  • Active Zone Minutes
    Get the results you want from every workout. Active Zone Minutes uses your heart rate to guide you toward your desired intensity level–then helps you get there.
  • Built-in GPS
    See your real-time pace & distance without your phone using built-in GPS during outdoor activity, then see a map of your workout route in the Google Health app.
  • 40+ Exercise Modes
    Fitbit Sense 2 tracks more exercises than ever–like skiing, golf, stand-up paddle boarding and more–and see all your stats in real time.
  • Notifications
    Get notifications for calls, texts, calendar events and apps like Gmail and Venmo–plus send quick replies and voice replies right from your wrist.⁴
  • Calls From Your Wrist
    Use the built-in mic and speaker to take Bluetooth calls hands-free, send callers to voicemail and adjust volume.⁴
  • Google Maps
    With Google Maps on your Fitbit watch, navigation is easier than ever. Explore a new route confidently with turn-by-turn directions on your wrist.⁴
  • Google Wallet
    Tap your wrist to pay everywhere Google Pay is accepted. The quick, secure and contactless way to check out with your watch.
  • Built-in Voice Assistant
    Use Amazon Alexa Built-in to get quick news and weather, set bedtime reminders and alarms, control your smart home devices and more–just by speaking to your watch.⁵
  • Unlock three months of Google Health Premium
    A health coach built with Gemini to deliver proactive, personal, and adaptive guidance for the whole you.²,⁶

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Specifications

Capacity & configuration

Band Type
Infinity
Display Type
AMOLED
Alert Type
Vibration
Replaceable Battery
No

Dimensions & weight

Product Name
Fitbit Sense 2 Advanced Health Smartwatch - Works with Android and iOS
Maximum Depth of Water Resistance
164 feet
Product Height
0.4 inches
Product Width
1.59 inches
Product Weight
0.083 ounces
Product Length
9.79 inches
Product Type
Activity tracker

Features

Color
Pale Gold - Aluminum - Infinity - Blue Mist, Graphite - Aluminum - Infinity - Shadow Grey, Platinum - Aluminum - Infinity - Lunar White
Brand
Google
Case Shape
Rounded square
Band Color
Blue Mist
Display Screen
Yes
Screen Size
40.5 millimeters
Touch Screen
Yes
Color Display
Yes
Clock Display
Yes
Backlit Display
Yes
Adjustable Brightness
Yes
Customizable Watch Faces
Yes
Operating System Compatibility
Android
App Compatible
Yes
Voice Assistant Built-in
Amazon Alexa
Data Plan Required
No
Wireless Connectivity
Bluetooth
Built-in Storage
0 gigabytes
GPS Enabled
Yes
Global Positioning
GPS
Mobile Notifications
Yes
Silent Alarm
Yes
Built-In Microphone
Yes
Metrics Measured
Activity vs. inactivity
Multi-Sport Tracking
Yes
Sensors
Accelerometer
Protective Qualities
Water resistant
Minimum Operating Temperature
-14.0 degrees fahrenheit
Maximum Operating Temperature
113 degrees fahrenheit
Minimum Wrist Size
139.7 millimeters
Maximum Wrist Size
220.98 millimeters
Size
Adjustable
Band Size
Adjustable
Rechargeable
Yes
Charging Interface(s)
USB-A
Battery Chemistry
Lithium-polymer
Band Material
Silicone
Case Material
Aluminum
Form Factor
Wristwatch
Year of Release
2022
Series
Sense 2
UPC
810073611436, 810073611429, 810073611443

Power & warranty

Model Number
FB521GLBM-US
Model Family
Fitbit Sense 2
Warranty - Parts
1 year limited
Warranty - Labor
1 year limited

Warranty & protection

Included manufacturer warranty

See manufacturer documentation.

Register your product with the manufacturer within 30 days of delivery.

Warranty service

Manufacturer warranty claims are handled by the manufacturer. We are happy to help you find the right contact: (888) 419-6820.

Customer reviews

Write a review
AnnetteMNov 4, 2026 · Verified purchase ★★★★★

Great watch! - Love all of the features! Battery lasts about a week before it needs to be charged. Features are easy to use and understand. Highly recommend

SUSANSNov 2, 2026 · Verified purchase ★★★★★

Fitbit Sense 2 - It is easier to maneuver than previous versions. I especially like that I can set the alarm directly on the Fitbit without syncing it with my phone.

BRYCEOct 30, 2026 · Verified purchase ★★★★★

Great product! - Awesome product, great apple watch alternative if you don't like wearing another phone on your wrist

BBshopperOct 28, 2026 · Verified purchase ★☆☆☆☆

Preowned it’s didn’t work smh - Bought multiple “excellent condition” preowned watches and had to return them all. Bad software and never connected. Geek squad couldn’t even help get them to work.

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Questions & answers

Ask a question

Email [email protected] or call (888) 419-6820 during business hours.

Free U.S. shippingOn every order. Leaves our store in 1–2 business days, arrives in 3–5 business days.
Free returns for 30 daysNo restocking fee. We email you a prepaid return label.
We can install it tooOptional in-home delivery, installation and haul-away on large appliances.
Talk to our team(888) 419-6820 · Mon–Sat