Fitbit Charge 3 vs. Fitbit Flex

Charge 3
 FitbitCharge 3Buy NowFitbitFlexBuy Now

Basic Info

Suggested Price$150$100

Activity & Fitness

Cycling (Bicycling)


Duration7 days5 days


Windows PhoneNA
WindowsNot yet




Resolution66 x 18NA
Size.721 inchesNA


Audio Speaker


Barometer or Altimeter
Ultraviolet Sensor
Water Resistance5 ATM1 ATM




Operating SystemNANA

Comparing Flex and Charge 3

The Fitbit Charge 3 and Fitbit Flex are two fitness trackers worth considering, especially for those looking to prioritize their health and activity goals. While both track basic activities such as steps, distance, and calories burned, their features diverge quite a bit as well. Navigating which one is right for your needs can be a challenge.

Choosing the right fitness tracker can make or break your commitment to staying active and reaching your fitness objectives. To make it easier, a detailed comparison of the Fitbit Charge 3 and Fitbit Flex is presented here, outlining design, features, user interface, pricing, and value. First, let’s look at Fitbit as a brand.

Fitbit has been synonymous with health and fitness wearables since its founding in 2007. Known for their reliable, user-friendly apparatuses, Fitbit has become one of the most trusted names in the wearable technology industry.

This comprehensive comparison will delve into the similarities and differences between the Fitbit Charge 3 and Fitbit Flex, evaluating the pros and cons of each device based on key aspects that can help you make an informed decision.

Design and Build

Fitbit Charge 3

The Fitbit Charge 3 features an aerospace-grade aluminum body and a flexible, durable wristband. It’s designed with a slim profile, weighing just 30 grams. The device has a grayscale OLED touchscreen display measuring 0.721 inches with a resolution of 66 x 18 pixels. The Charge 3 is water-resistant up to 5 ATM.

Fitbit Flex

On the other hand, the Fitbit Flex is a simpler, more lightweight design with a wristband made of elastomer material. It does not have a traditional display screen. Instead, it features a basic LED light indicator system to display progress. The Flex is also water-resistant but only up to 1 ATM.

Comparison of Design and Build Quality

Comparing the design and build quality of the Charge 3 and Flex, it’s clear the Charge 3 is the more robust option. With its aluminum body, touchscreen display, and better water resistance, the Charge 3 outperforms the Flex in terms of design and durability. The simpler design of the Flex, however, may appeal to those seeking a minimalistic approach.

Features and Functionality

Fitbit Charge 3

The Fitbit Charge 3 is packed with features, including heart rate monitoring, sleep tracking, and dedicated tracking modes for various activities like cycling and swimming. It has a 7-day battery life on a single charge and is compatible with Android, iOS, and Windows Phone devices. Other notable features include text, email, and phone notifications, Bluetooth connectivity, and NFC (in select models).

Fitbit Flex

The Fitbit Flex is a more basic fitness tracker with a focus on steps, distance, and calories burned. It also includes sleep tracking but lacks advanced features such as heart rate monitoring or specific workout modes. The Flex has a battery life of 5 days and is compatible with Android, iOS, Mac, and Windows devices. It also has Bluetooth connectivity and vibration for alerts and alarms.

Comparison of Features and Performance

When comparing features and performance, the Fitbit Charge 3 stands out due to its comprehensive suite of activity tracking capabilities and longer battery life. The Fitbit Flex may be a good option for those seeking a more basic fitness tracker without the bells and whistles of more advanced models.

User Interface and User Experience

Fitbit Charge 3

The Charge 3's user interface consists of a touchscreen display with customizable clock faces and app shortcuts. Fitbit’s proprietary operating system ensures seamless navigation between features and compatibility with a variety of smartphone devices. Its compatibility with Fitbit’s wide range of apps further enhances the overall user experience.

Fitbit Flex

With no touch display, the Fitbit Flex relies on LED light indicators and vibrations to provide feedback and progress updates. Paired with the Fitbit smartphone app, users can track their activity and set goals using the familiar and user-friendly interface of the mobile app.

Comparison of User Interface and User Experience

The more advanced nature of the Fitbit Charge 3's user interface and the additional features it offers makes for a more engaging experience compared to the basic Flex design. However, the simplicity of the Flex may be seen as a positive for some users who prefer less complication in their fitness tracker.

Price and Value

Fitbit Charge 3

The Fitbit Charge 3, with its more extensive feature set and advanced design, comes in at a higher price point of around $150.

Fitbit Flex

As a more basic fitness tracker, the Fitbit Flex has a lower price, sitting at around $100.

Comparison of Price and Value

When comparing the price and value of the Fitbit Charge 3 to the Fitbit Flex, the Charge 3's higher price may be justified by its additional features and more advanced design. However, the Flex offers a more affordable option for those on a tighter budget or interested in basic fitness tracking without added complexities.


Ultimately, choosing between the Fitbit Charge 3 and Fitbit Flex comes down to personal preference and individual needs. The Charge 3 is designed for those interested in a more comprehensive fitness tracker with a greater number of features and a more advanced design. The Fitbit Flex, on the other hand, is a solid but more basic alternative for users looking for simplicity and affordability in their fitness tracker.

Frequently Asked Questions

Can the Fitbit Charge 3 and Fitbit Flex track swimming?

The Fitbit Charge 3 is suitable for swimming tracking, whereas the Fitbit Flex lacks this ability due to its more basic design and lower water resistance.

How do Fitbit Charge 3 and Fitbit Flex fare in terms of battery life?

The Fitbit Charge 3 has a battery life of up to 7 days, while the Fitbit Flex can last up to 5 days on a single charge.

Which Fitbit is better for monitoring heart rate?

The Fitbit Charge 3 is better equipped for heart rate monitoring as it comes with a built-in heart rate sensor, whereas the Fitbit Flex lacks this feature.

Does the Fitbit Charge 3 have a color display?

No, both the Fitbit Charge 3 and Fitbit Flex do not have color displays. The Charge 3 uses a grayscale OLED touchscreen, and Flex uses LED light indicators instead of a screen.

Can both Fitbits receive notifications from smartphones?

Yes, the Fitbit Charge 3 can receive call, text, and email notifications from compatible smartphones. The Fitbit Flex can receive notifications through its vibration feature but does not display the content of the notifications.

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