Fitbit Flex vs. Fitbit Air: New $99 tracker offers 7-day battery, advanced metrics
The Fitbit Air is the superior choice for anyone seeking a no-fuss, comfortable activity tracker, offering a comprehensive suite of modern health metrics for the same price as its 2013 predecessor, the Fitbit Flex.
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Fitbit Flex vs. Fitbit Air: Tracking Capabilities
The original Fitbit Flex, released in 2013, was limited to tracking only steps and sleep. While 13 years later, the Fitbit Air now measures heart rate, blood oxygen, and skin temperature, alongside a sleep and readiness score, and workout tracking.
The data from the two devices on basic metrics like steps and sleep was surprisingly close in testing.
During a trial, the Flex recorded 9,093 steps with 6 hours and 22 minutes of sleep, earning an 83 sleep score.
The Air logged 9,285 steps and 6 hours and 13 minutes of sleep, though it did not assign a sleep score. The brittle rubber strap on the Flex also broke after a couple of days of use.
Fitbit Flex vs. Fitbit Air: Design and Comfort
The Fitbit Air offers a discreet, screen-free design intended to be barely noticeable during daily routines. In contrast, the Fitbit Flex had a bulkier rubber strap. The Air’s woven fabric strap is described as 10 times more comfortable than the Flex’s original rubber band, enhancing overall wearability.
While the Flex featured a row of blinking LEDs to indicate step progress, the Air’s lack of a screen requires users to check their phone for real-time data. This can ironically lead to more screen time if not managed carefully, detracting from the device’s discreet nature.
Fitbit Flex vs. Fitbit Air: Price and Value
The Fitbit Air launched at $99, matching the original $99 price of the Fitbit Flex from 2013. In the UK, the Air costs £84, a slight increase from the Flex’s original £79. The Air received a 4-star rating in a March review, highlighting its value despite a mandatory subscription for advanced features.
Accessing the full potential of the Fitbit Air, including AI-powered insights and trend analysis within the Google Health app, requires a subscription. This premium service costs $9.99 per month or $99 annually, adding a recurring cost to the tracker’s value proposition.
Fitbit Flex vs. Fitbit Air: Battery Life and Convenience
The Fitbit Air boasts a significantly improved battery life, lasting seven days on a single charge, compared to the Fitbit Flex‘s five-day capacity. Even a 13-year-old Flex unit, after years in storage, managed to hold a charge for just over two days.
A key convenience improvement in the Air is its automatic tracking of sleep and workouts. The Flex required manual activation for sleep mode and lacked any workout logging function, a feature that often led to missed sleep data in the past. For auto-logging, activities must last at least 15 consecutive minutes.
| Feature | Fitbit Flex (2013) | Fitbit Air (2026) |
|---|---|---|
| Price | $99 / £79 | $99 / £84 |
| Battery Life | 5 days | 7 days |
| Tracking Capabilities | Steps, Sleep | Steps, Sleep, Heart Rate, Blood Oxygen, Skin Temperature, Sleep Score, Readiness Score, Workout Tracking |
| Strap Material | Bulky Rubber | Breathable Woven Fabric |
| Screen | LED Indicators | None |
| Automatic Tracking | No | Sleep, Workouts (15+ min) |
| Subscription Required | No | Yes (for premium insights) |
Frequently Asked Questions
What are the main differences in tracking between the Fitbit Flex and Fitbit Air?
The Fitbit Flex tracked only basic steps and sleep, while the Fitbit Air adds heart rate, blood oxygen, skin temperature, sleep and readiness scores, and workout tracking.
Is the Fitbit Air more comfortable than the Fitbit Flex?
Yes, the Fitbit Air features a breathable woven fabric strap that is 10 times more comfortable than the bulky rubber strap that came with the Fitbit Flex.
How does the battery life compare between the two devices?
The Fitbit Air offers a longer battery life of seven days on a single charge, whereas the Fitbit Flex could only manage five days.
What is the price of the Fitbit Air compared to the Fitbit Flex?
Both the Fitbit Air and the original Fitbit Flex launched at a price of $99. The UK price for the Air is £84, slightly higher than the Flex’s original £79.
Buy Fitbit Air if: you want a comfortable, discreet tracker with modern health metrics and appreciate the convenience of long battery life and automatic activity logging, and are willing to pay for a premium subscription for deeper insights.
Buy Fitbit Flex if: you can find one and only need basic step and sleep tracking, prefer a device with some visual feedback on progress without needing your phone, and want to avoid any subscription fees.
