The Best Fitbit
The best Fitbits will accurately track your vital signs and movements while being comfortable and stylish. We brought in every Fitbit and their most popular accessories and tested them over two weeks to find out which ones combine accuracy and comfort for a fitness tracker you’ll love. Our top three picks beat out the competition for accuracy and all have a different look.
The Charge 2’s black sporty band frames a narrow screen that displays your vital signs. It ties with the Ionic for accuracy, soaring above the “good enough” attitude of most fitness trackers. We liked that the Charge 2 is full of features an intuitive to use. For a simple fitness tracker for walking around the neighborhood or sweating it up in spin class, the Charge 2 is our favorite Fitbit.
A fitness tracker that doesn’t look like a fitness tracker. Accurate and tiny, the Flex 2 has no heart rate tracker and small notification lights in place of a screen. But it has most of the features of the Charge 2, you just need to use the app to see your data.
The Ionic has a beautiful full-color screen, and looks more watch than fitness tracker. It builds on the Charge 2’s features with built-in guided workout programs.
The Best Fibit
The Charge 2 ($150) is our top pick, with a slim screen and narrow band that make it look like a slender watch. It records steps, distance, heart rate, and offers activity tracking. We loved how easy it is to navigate, with a simple click-through button to see your vital signs. There’s also a responsive tap mechanism to switch between activity types, so you can label your exercise as Run, Weights, Treadmill, Workout, Elliptical, Bike, or Intervals. The Charge 2 is a great all-around device to keep you on track for your fitness goals, but it’s only rainproof -- best to take off if you’re doing the dishes or going swimming.
For a fitness tracker that won’t draw attention to itself, but also tracks your steps, distance, and activity levels, the Flex 2 ($60) is streamlined and inconspicuous. The actual tracker is a miniscule device, smaller than a AAA battery, that fits into a slim silicone-like band. It has five small lights that will notify you in a quick glowing pattern if you’ve received a text or a phone call, or will send you movement reminders to keep you on track for your daily steps. It doesn’t have a heart rate sensor, but it is swim proof -- up to 100 meters deep.
If you’re looking for an all-in-one device to track your vital signs and exercise activities, with the benefit of a video “trainer” to motivate you through a quick work-out, the Ionic ($300) is your Fitbit. It has all of the features of the Charge 2 and then some. As a smartwatch, the Ionic comes with a few bonus features: you’ll be able to store music directly on it, and stream straight to a pair of bluetooth headphones, so you don’t need to carry your phone with you on your morning walk. It has a large, high-definition color touchscreen that’s really responsive, as are the three navigation buttons. And you can make payments with it, if you feel like leaving your wallet at home.
How We Found the Best Fitbit
The Best Fitbit needs to be accurate
Whether you’re training for a race, taking a walk around the neighborhood, or looking to lose or gain weight, accuracy is important. Accurate data will help you figure out how long you spent in each heart rate zone, how many steps you took today, and how quickly you ran that last mile.
From our testing experience with Best Fitness Tracker, and from research in the Fitbit community forum, we expected some Fitbits would perform better than others for measuring certain metrics. Most of the forum users estimate that their data is off by about 10%, though this will vary depending on which Fitbit you have (and the Fitbit technology available during its production). Accuracy also depends on you. Fitbit makes certain assumptions about users when they configure their algorithms for distance traveled or calories burned. Some of this is adjusted by the data you share with Fitbit, like your height and weight. Fitbit also has tips for calculating your stride length, which you can manually enter to increase distance accuracy.
Fitbits aren’t great for calorie tracking.Even if Fitbit measured all of its promised data accurately, there are a lot of variables that go into how your particular body consumes, uses, and stores energy that affect calorie tracking. Fitbit currently doesn’t calculate or adjust for individual metabolisms.
Fitbit uses all of these data points to figure out how many calories you’ve burned. While having a small discrepancy in heart rate may not matter if your Fitbit is nearly perfect at measuring distance and steps, when multiple figures are off, it’s hard knowing if you’ve really burned 100 calories, or just 50.
We wanted to find which Fitbits were the most accurate in all three categories used to calculate your fitness achievements: counting steps, tracking distance, and reading heart beats. None of the Fitbits were right 100% of the time, but we preferred Fitbits that got closest and were off by the same amount every time. Like adjusting for a clock that runs 5 minutes slow, it’s possible to adjust for a Fitbit that always thinks we walked 10% fewer steps than we did. But a Fitbit that sometimes overestimates our heart rate, thinking we worked harder than we did, and underestimates the rest of the time is self-defeating.
We ran each Fitbit through three identical tests. We counted out 300 steps while wearing a heart rate chest strap -- these track the electrical signal emitted as your heart contracts and are much more accurate than wrist wearables -- and we used the app for our chest strap to keep track of how far we ran. Then we looked at our Fitbit stats and noted:
- Number of Steps. The Zip was the most accurate, reporting that we’d taken 301, 304, and 300 steps. On the other hand, among the worst for accuracy were the Alta, which both over- and underestimated by as many as 100 steps, while the Alta HR missed at least 50 steps in each test. Both the Charge 2 and the Ionic did well here, only adding one or two steps for every 100 that we took.
- Number of Miles. The Charge 2 was the most accurate for distance. The Ionic came close, but occasionally would read .14 miles travelled instead of .15. On the other hand, the Blaze was the worst at measuring distance, and frequently underestimated us by nearly 20%, meaning that it read .13 miles when we had gone .16 miles.
- Average and Maximum Heart Rates. While the average heart rates for our test came out fairly similarly, we gave preference to a Fitbit with a narrow range of error over a wider one. While tracking heart rates is tricky for any light-based device, a narrow range of results indicates greater consistency in measurement. Most of the Fitbits underestimated average and maximum heart rate by about 10%. But where the Blaze would underestimate by 6 to 7 heart beats every time (like that clock that’s consistently a few minutes slow), the Surge sometimes overestimated by 17, and sometimes underestimated by 12. The most accurate, the Ionic and the Charge 2, had the smallest ranges in both average and maximum heart rate (around 5-8 bpms off), and were the most consistent.
Fitbit calls its technology “PurePulse,” which seems to use photoplethysmography to count heart beats. The red color of blood means it absorbs green light. As your heart beats, more or less light will be absorbed depending on whether your heart is expanding or contracting. By flashing green lights at your skin, Fitbits tracks when less light is absorbed than usual, and estimates your heart rate from that.
Your Fitbit should be easy to use
After testing for accuracy, we looked at whether each Fitbit was easy to adjust and intuitive to use. We gave points to devices that were straightforward and accessible and dinged those that we had to fight with simply to see our daily stats (we’re talking about you, Zip).
Fitbits typically use two methods to scroll through different screens: clicking and tapping. Testers unanimously preferring the ability to click rather than being forced to tap. The Zip, Alta, and Alta HR operate by tapping through each screen to view time, steps, distance, and calories burned. But since they didn’t always respond to the first (or second) tap, we sometimes found ourselves furiously jabbing at our wrists to get our tap to register. We then ended up over-tapping and completely skipping the stats we actually wanted to check and had to tap back through the sequence. Our testers weren’t impressed.
The Charge 2 offers hybrid input: a side button to click through the main pages, but you need to tap to scroll through extra options on each page. So you click through to heart rate, and tap to switch from current to resting, and then click over to exercises, and tap from Run to Weights, Elliptical, etc. The Charge 2’s tap is fairly responsive (though it does miss the occasional one).
The smartwatches take things to the next level with a touchscreen. With their larger, color screens the Blaze and the Ionic are visually appealing and offer more icons and more pages. Their touchscreens are much more responsive than the tapping screens of their smaller siblings, so we never had to fight to change a screen. In addition to the touchscreen, they each have three buttons for easy navigation. We were concerned that with more options (read: rabbit holes to get lost in) the smartwatches would be more difficult to navigate than the simpler wristbands, like the Charge 2. But none of our testers had a problem learning the different buttons to move between pages and backtrack to the main menu. Instead, everyone found the Blaze and Ionic to be extremely intuitive, and no one had trouble getting the touchscreen to respond.
It also needs to be comfortable
Fitbit makes bands in two different styles. Most use a standard watch-style band with a small buckle, but both the Flex 2 and the Alta come standard with a two-pronged hole-punch band instead.
Like the polarizing click or tap results, testers universally agreed that the hole-punch bands were uncomfortable and difficult to put on properly. Several testers found that the prongs were too loose, and the Fitbit would fall off their arm unexpectedly. On the other hand, some found the prongs couldn’t fully insert into the band without jabbing into their wrist. While we fought to put on the Flex 2, once on, we also fought to take it off, which made finding the right fit a challenge. One tester with sensitive skin struggled to remove the Flex 2, and had a small rash where it rubbed against her skin as she pried it loose. Testers preferred the buckle clasp of the watch-style bands: they were easy to put on, take off, and adjust.
Your Fitbit Should Feel Loose For most of the day, it’s best to make sure you can fit two or three fingers between your Fitbit and your wrist to ensure a comfortable fit. But during exercise you’ll want to wear it snug against your wrist. for your Fitbit to have the best chance at tracking your heart rate.
We asked testers whether each Fitbit was comfortable and if they’d consider wearing it all day (and night) long. This is where personal preference started to show. Certain Fitbits were comfortable for some people, but uncomfortable for others (except for the Surge, which was panned by all for being bulky and unwearable - perhaps an insight as to why it was discontinued). While some preferred the narrow face of the Altas, others liked the wider face and broader band of the Charge 2. Although similar in size, the Blaze’s slightly wider screen and lower profile were favored over the bulkier Ionic, although the Ionic actually appears sleeker in style with its smooth band transition.
If you’re considering a Fitbit more for daily step tracking and heart rate than heavy duty workouts, it may be worth investing in a different band than the standard silicone-like one that comes with each Fitbit. Testers greatly preferred the extra leather bands (available for every style) that we ordered for the Ionic and the Alta, which were more comfortable and less conspicuous. That said, they’re not great if you’re getting sweaty at the gym. Getting a new band, in whatever material, is also an easy way to mix up your style with a new color, or sidestep the two-prong fastener problem if you go for the Flex 2.
Our Picks for the Best Fitbit
Best Overall Fitbit
The Charge 2 tracks your steps, heart rate, and miles in a device that looks like a small watch. Testers loved using the Charge 2’s button to cycle through the display options, with many commenting it was much more reliable than the tap-method of the Alta and Alta HR. It’s easy to click through to see your daily steps, calories, and current heart rate, as well as activate a run exercise, use the stopwatch, or start Fitbit’s guided relaxation exercise.
With a small buzz, you’ll be able to see any texts or phone calls on the Charge 2’s screen, and can decide whether to stop your workout for an important message, or leave your phone in your gym bag. If you’d prefer your gym time (or any other time) to be strictly offline, it’s easy to disable notifications, too.
The Charge 2 was highly accurate at estimating how many miles we traveled, though it consistently underestimated our heart rate (both average and maximum) by about 10%, while overestimating our steps by 4%. For every 100 steps we took, it credited us with an extra four. Not perfection, but unlikely to make a huge difference by the end of the day. Both Altas were huge under-counters, missing on average 22% of our steps, and sometimes adding 16% more.
Additionally, the Charge 2 comes with a watch-style band that testers found easy to adjust and pleasant to wear. Our testers initially thought that the Charge 2’s default silicone-like band would be uncomfortable, or would pull on their arm hair, as it did with the Altas, whose slim bands move more often across the wrist. However, while the Charge 2 is made of the same material, its broader band helps it stay comfortable. Replacement bands are available through both Fitbit and Amazon.
Most of our testers liked having the broader screen of the Charge 2 compared to the Altas. It fits more information on the screen at a glance, and because it’s broader, it lies more evenly on the wrist. If you’re looking for something less conspicuous, and don’t need a screen, go for the Flex 2 for half the price.
Best Incognito Fitbit
Except for its small, color-coded lights, the Flex 2 isn’t flashy, and that’s a good thing if you’re looking for a fitness tracker that doesn’t look like a fitness tracker. Outside of the band, the device is tiny, smaller than a AAA battery. This makes it one of the easiest to customize, as both Fitbit and Amazon offer a variety of bands, jewelry-styled bangles, or necklaces for your Flex 2.
The Zip: Fitbit’s Step CounterThe Zip was one of the most accurate Fitbits for counting steps, tied with the Ionic. Both were accurate 99.5% of the time. We didn’t like the Zip because of its inconsistent tapping mechanism, and the screen isn’t backlit, making it hard to read sometimes. But it is only $60.
If you don’t want to add another screen to your life, the Flex 2 has most of the same functionality of the Charge 2, just without the digital display. Both have reminders to move (hourly check-ins to make sure you get in Fitbit’s recommended 250 steps per hour), track steps and miles, and notify you of texts and calls.
The biggest drawback is that the Flex 2 doesn’t have a heart rate tracker, and while it was more accurate than some devices (the Alta HR, the Blaze, and the Alta) for steps and miles, it’s not in the overall top five for accuracy, either. It underestimated steps by 4% to 13% and underestimated our miles twice by 14%, but overestimated once by 6%. While we weren’t fans of this inconsistency, the Flex 2 is the only low-profile, budget Fitbit that has almost all of the features of its larger siblings. For more accuracy, you may either need to go with fewer features, to a dedicated step counter like the Zip, or go larger, either to the Charge 2 or the Ionic.
Best Smartwatch Fitbit
The Ionic is Fitbit’s latest foray into smartwatch territory and is remarkably accurate. It almost perfectly counted our steps -- it was accurate 99.5% of the time. It tracked distance with near-similar precision (98%); only the Charge 2 beat it for accuracy (99%).
While the Ionic struggled a bit with average and maximum heart rate, so did Fitbit’s other smartwatch, the Blaze. The Ionic had a narrower range of error, making it more consistent than the Blaze. Both the Ionic and Blaze underestimated average heart rates about the same; the Ionic was off by 6-14 bpm, while the Blaze was off by 1-10 bpm. However, the Ionic was more consistent when it came to maximum heart rate; its range of bpms during our tests (-1 to -12 bpms) was much smaller than that of the Blaze (-4 to -18 bpms).
We Value Consistency Over AccuracySince no Fitbit is 100% accurate, we need to be able to trust that even if they aren’t measuring accurately, they’re measuring in the same way each time. We can adjust for a Fitbit that undercounts our steps by 10% each time, but not one that sometimes undercounts by 10%, and sometimes over counts by 5%.
With three buttons and a touchscreen, our testers found the Ionic easy to use, and quickly learned how to access different exercise routines, adjust settings, and play music. When you start up an exercise routine, the Ionic will isolate that data and sync it into your Fitbit app, so you can see how effective your workout was, outside of your daily statistics. We liked the three guided workouts available through an app called Fitstar. Activating them guides you through a quick (5-10 minute) interval-based workout where each activity is demonstrated and then a timer starts. The Ionic is also one of two Fitbit devices that say they are water-resistant (the other is the Flex 2). If you keep the Ionic skin-tight, you’ll be able to track your heart rate while swimming, so long as you don’t dive below 50 meters.
Our testers had mixed feelings about the comfort of the Ionic. They universally preferred the extra accessory leather band (purchased separately) over the silicone-like band that comes standard. The soft leather helped the Ionic blend in as a watch more than the sporty-like rubber wristband did. The Ionic arrives with the Pandora app ready to download a playlist, but it can also store and play hundreds of songs directly to your bluetooth headphones. Additionally, if you’ve added a credit or debit card into the Fitbit app, you’ll be able to use the Ionic to make payments. However, Fitbit’s own app store is still in the beginner stages and you can’t download apps from the Google, Android, or Apple stores. While we loved the screen quality of the Ionic, that high-definition screen and other smart features come with a hefty price tag.
Fitbit Features Compared
All three of our top picks measure steps, distance, calculate calories, track sleep, give reminders to move, and have call and text notifications.
|Charge 2||Flex 2||Ionic|
|Waterproof||N||Y (up to 50 meters)||Y (up to 50 meters)|
|Guided Breathing Mode||Y||N||Y|
|Apps, Music, Payments||N||N||Y|
|Step Accuracy*||approx. +4% (extra 4 steps for every 100)||approx. -1% to -13% (minus 1-13 steps for every 100)||approx. -0.05% (<1 step for every 100)|
|Distance*||100% accurate**||92% accurate (inconsistently +/-)||97.6% accurate (approx. -2.4%)|
|Heart Rate Avg*||approx. -10% (-5 to -10 bpm)||n/a||approx. -10% (-6 to -14 bpm)|
|Heart Rate Max*||approx. -8% (-11 to -19 bpm)||n/a||approx. -8% (-1 to -12 bpm)|
*Based on our test results
**Within 1/100th of a mile
Did You Know?
The Fitbit app is pretty swag
We loved the Fitbit app, which has multiple categories and screens that are easy to use.
When you first start up the app, you’ll be directed to the Dashboard, which has all of your statistics for the day so far. As you get closer to your daily goal (first set up when you start your account and adjustable in your Account Information), the blue track meter fills up. Clicking on any of these small icons (Steps, Floors, Miles, Cals, and Minutes) will show you how often this week you’ve completed each goal, and stores past data for comparison.
Of the larger icons, two operate in the same way as these smaller ones. Clicking on Steps Per Hour or the Heart Symbol will take you to your daily and weekly figures for whether you’ve met your hourly step goal, and a line chart of what your heart rate was over the day.
Clicking on the Sleep Tracking Icon brings you into a detailed analysis of how you slept the previous night. You’ll be able to see how often, how long, and when you were awake, in REM, light, and deep sleep, and track your patterns over time.
There are also Weight, Water, and Food icons, where you can input what you’ve had to eat or drink so far today, as well as track your weight. If you purchase Fitbit's Aria 2 scale, it’ll sync your weight data automatically. The Food Tracker lets you scan a barcode, or manually enter in what you ate for lunch. If the food isn’t in their database, you might need to enter in the calories.
We loved how easy it is to simply tap in a glass of water into the Fitbit tracker, and how the Food Tracker calculates not only how many calories you eat, but also splits the nutrients into macronutrients: Carbohydrates, Fats, and Protein.
Weekly Exercise shows your daily and weekly stats for activities that you’ve recorded. It also is where you can log in an exercise if you forgot to activate the feature in the moment, and where you can start an exercise session. Since the Flex 2 doesn’t have a way to activate a session in the Fitbit itself, you’ll need to either use the app ahead of time to start and end your activity, or keep track of the time and manually log it later.
Aside from the Dashboard, there are several pages that are fun to play around with, and help fit a short walk or quick exercise session into your day. Fitbit splits its Challenges page into a few categories. With Adventure Races, you can challenge your friends to compete according to distances/steps of real life locations, like popular sightseeing spots Yosemite National Park, and New York City.
The community is one of the best things about Fitbit, and Fitbit knows it. In addition to being able to link to your friends, you can connect to various groups based on shared interests. Once in a group, you can see recent posts people have made about their own fitness journeys, ask questions and receive tips, and chime in with your own advice and encouragements.
We also liked the Guidance page in the Fitbit app. Like the Ionic’s Fitstar app, which has three guided workouts to help you get in a short workout, the Guidance page suggests workouts for you. It does require the Fitbit Coach app and subscription, which costs $40 per year. You won’t be able to watch even these sample workouts without it, but if you purchase it and the Ionic, you’ll be able to customize the workouts stored on your watch.