What is a Fitbit and how does it work? Plus, everything you need to know about setting up your Fitbit

This editor's guide explains exactly what a Fitbit is and how to set up your new device from scratch

Woman holding smartphone with headphones in by the beach, looking at smartwatch on wrist after learning what is a Fitbit and how to use one
(Image credit: Getty Images)

You've probably wondered what is a Fitbit a few times if you've recently delved into the world of fitness trackers. As they're some of the most popular smartwatches and trackers on the market, suitable for everyone regardless of experience, they're pretty much everywhere. 

Whether you're thinking about buying one or have already scored your pick of the range, we're here to help you answer all your burning questions from 'what is a Fitbit?' to 'how does a Fitbit work?' and we'll even explain step-by-step how to set up a Fitbit from scratch.

While there are lots of similar activity trackers out there, as the health editor of woman&home and a keen runner, cyclist, and weightlifter, I've always come back to Fitbit whenever I need an upgrade. Having owned three of the best Fitbits over the years - my favorite so far being the Fitbit Versa 3 - there's not a lot I don't know about the trackers and how to get the most from them, so I've got you covered. 

What is a Fitbit?

A Fitbit is an activity tracker worn on the wrist just like a watch. It tracks your day-to-day activity automatically across a range of exercises like walking, running, swimming, cycling, or gym activity, and then stores this information in an easily-accessible app on your phone. There are two main types to choose from: trackers and watches. Trackers, like the Fitbit Charge 5, are smaller and focused more on tracking and activity, while the watches also offer features compatible with smartphones, like receiving text, call, and calendar notifications. 

Regardless of the types of Fitbit you choose, all of them have some features in common like all-day heart rate tracking, step counting, calorie burn, and a range of pre-programmed exercise modes to choose from. 

The newer smartwatch models can also track your menstrual cycle, stress levels, and offer notifications if it detects an irregular heartbeat, among other advanced features, to give you an overall picture of your health. Other fun features on some models include on-screen workouts, breathing meditations, and Fitbit Pay, which can be helpful if you don't want to go out with your purse. 

Fitbit offers so many versions, there really is something for everyone in the lineup, whether you want an all-singing-all-dancing smartwatch that syncs with your smartphone, or you just want to track your distance and figure out how many miles 10,000 steps is, there's certainly going to be a model that's right for you. It's just one brand in a whole market of fitness trackers though. If you want something specifically orientated towards running, cycling, or golf, it's worth considering Garmin vs Fitbit before investing.

How does a Fitbit work?

  • Activity tracking: All Fitbit trackers and watches use a 3-axis accelerometer to track your motions, using algorithms designed to look for specific movement patterns. Some devices also include an altimeter to detect whether you are moving up or down the stairs. As you move, your Fitbit will estimate your steps, distance and calories burned, which you can view on the tracker's face or via the Fitbit app. 
  • Heart-rate tracking: Photoplethysmography (PPG) technology uses light to monitors the volume of blood in your wrist and determines how many times your heart beats per minute. This number is displayed on your watchface at all times, unless you turn it off. 
  • Sleep tracking: One of the best features of the Fitbit outside of the exercise modes, in my opinion, is the sleep tracking. With your permission and only if you wear the tracker while you sleep, Fitbit tracks your patterns by using heart rate sensors and motion detectors through the night. In the morning, the data is delivered as a personalized Sleep Score in the Fitbit app, telling you just how well you slept.
  • Exercise tracking: When it comes to how much exercise per week you need to do, the general recommendation by the World Health Organization is 150 minutes moderate activity or 75 minutes of vigorous activity. Fitbit will automatically set your weekly target at 150 Active Zone Minutes and as you work out, it will tally up your effort by tracking Fat Burn, Cardio, and Peak activity. For every minute you spend in the Fat Burn Zone, you'll earn 1 Active Zone Minute, and for every minute you spend in the Cardio or Peak Zones, you'll earn 2 Active Zone Minutes. The zone you're in is determined by your heart rate and how hard you're working out, a statistic you can see throughout your workout on the tracker or watch. 
  • Other metrics: Some Fitbits can also track more health metrics and help you tune into your body that little bit more. However, in some cases, you will need to purchase a Premium membership to do so, which syncs with the smartphone app. Health metrics that are only available with a membership include oxygen saturation (SpO2) measurements, skin temperature tracking, breathing rate tracking, and heart rate variability.
  • Access to the Fitbit app (free version): If you buy a Fitbit, you can automatically sign up to the Fitbit app for free. I'm always impressed with the range of amazing free insights offered by the app, everything from your weekly step total to an analysis of how well you slept over the last seven days. You can also use the water and food logging features to ensure you stay on top of your hydration and nutrition goals. 

A demonstration of the sleep tracking software on the Fitbit

(Image credit: Grace Walsh/Future)

What is the latest Fitbit? 

The Fitbit family is huge and ever-growing, constantly adding to its lineup with new and improved models. Currently, the latest models are the Fitbit Sense 2, Versa 4, and Fitbit Inspire 3

The Sense 2 and Versa 4 are both sleek smartwatches, upgrades to their predecessors with a range of new features like all-day body response tracking, a personalized sleep profile, and access to Google Maps and Google Wallet. The Inspire 3 is an upgrade to the hugely popular Inspire 2, a smaller and more lightweight fitness tracker in various new and exciting colors. 

Each of them is water resistant up to 50 meters and has a battery life of at least six days or more. They all also track the essentials like steps, distance, calories burned, activity, sleep, and menstrual cycle. 

How to set up a Fitbit

If you've already got your device, the next thing you'll be wondering if how to set up a Fitbit. The good news is, these are the easiest fitness trackers to set up and use. 

Here's how to set up a Fitbit in five easy steps: 

1. Download the Fitbit app

A panel showing how to download the Fitbit app

Fitbit is a free app available on Apple's Appstore and the Google Play Store. 

(Image credit: Grace Walsh/Future)

You'll find the Fitbit app on Apple's Appstore or Google Play Store on your smartphone. It's completely free to download but you'll need an account with your chosen app store to be able to download the app. 

2. Charge your Fitbit

A demonstration of how to charge your Fitbit, with both a fitness tracker and smartwatch example

The charging point on a Fitbit tracker (left) will be slightly narrower than a smartwatch (right). 

(Image credit: Grace Walsh/Future)

Using the charging cable provided, charge your Fitbit. All of them will come with a charging cable suitable for the device and it will be a magnetic plate that you attach to the underside of the Fitbit face. When the Fitbit is charging, the screen should light up with the Fitbit logo and have a picture of a battery on the screen and the percentage level the device is currently at. 

3. Turn on your device

Once your Fitbit has charged, turn on the device if it doesn't come on automatically. You'll be able to do this by using the button on the side of the device or tapping the screen. 

When the device is on, it will be waiting for you to connect it to the Fitbit app so follow on for the next step. 

3. Set up an account on the app and fill in your profile

Opening page for the Fitbit app

(Image credit: Getty Images)

Now you've downloaded the app, click on the 'Join Fitbit' button. This will immediately take you through to a page where you can select the model of Fitbit you've bought. From here, the process depends on the model but the instructions are very easy to follow in my experience. 

You'll also need to set up your profile. To do so, click on the profile icon in the top right-hand-side of the screen. This is where you'll be able to fill in the details of your current health status (like your height and weight to more accurately predict calorie burn) and you can set fitness goals to track specific metrics here too. 

4. Start trying out all the features

A demonstration of the exercise running mode on the Fitbit Versa 3, something to try after learning what is a Fitbit

From the homepage (left), you can easily swipe to access the exercise programs (middle) and start a workout (right).

(Image credit: Grace Walsh/Future)

Then it's time to have fun with your tracker or smartwatch! Whether you've gone for the newer models or an older classic like the Fitbit Charge 4, you can easily swipe through the options and explore the different workout settings. 

If you run into any issues, refer back to the instructions for your Fitbit. These will be included in the box that the device and charger came in. You can also have a look at our troubleshooting advice below.

How to charge a Fitbit

All Fitbit devices come with a rechargeable battery and a charging cable. You can use the charging cable to charge a Fitbit device just like you charge a smartphone, except it will be a magnetic charging point rather than a USB one. 

Simply plug the charging cable into a computer, a UL-certified USB wall charger (such as an iPhone or Android wall charger), or a DC-to-USB adapter (car charger), as Fitbit’s official website suggests. 

Here's what to do if you encounter issues when trying to charge your Fitbit: 

  • Avoid using a USB hub. Try plugging the charging cable into a different USB port or wall charger.
  • Try restarting your tracker.
  • Clean the contacts on your tracker and the pins on your charging cable. Use a toothpick, toothbrush or cloth. Ensure it's totally dry before plugging in to charge. 

How to alter the time on a Fitbit device

Want to know how to change the time on a Fitbit? As you connect your Fitbit to the Fitbit app via your phone or computer, the time displayed on your Fitbit should match the time on the mobile device or computer it has been paired with. If the wrong time is showing:

  • Try manually syncing your tracker with your device.
  • Ensure your tracker is running the most up-to-date firmware.
  • Select the correct time zone using the Fitbit app. Tap or click the account icon, select 'time zone' under 'advanced settings' and turn off the 'automatic' option. Tap or click 'time zone' and select the correct time zone. Sync your tracker.
  • Select the correct time zone on the Fitbit.com dashboard. Log in and click the gear icon in the top right-hand corner. In 'settings', scroll to the bottom of the “personal info” page and modify the time zone. Force sync your tracker by clicking the Fitbit Connect icon near the date and time on your computer and selecting 'sync now'.

How to sync a Fitbit

If your Fitbit tracker is paired with the Fitbit app on a mobile device, it will sync every time you open the app. You can also set it to sync periodically throughout the day by turning on All-Day Sync. Alternatively, on the homepage of the app, pull down from the top and this will manually begin a sync of your Fitbit. 

When the sync is done, which I've found can take a couple of seconds if you haven't synced your tracker in a while, there will be a green tick at the top of the page in the sync bar. This is also a great way to check how much battery your Fitbit has left. 

If your tracker is synced with a computer and Fitbit Connect, it will automatically sync every 15-20 minutes, assuming the tracker and computer are in close proximity and the wireless sync dongle is plugged in, if applicable. You can manually initiate sync by touching the tracker image at the top of the screen and pulling it down.

A demonstration of how to sync a Fitbit on the app

Look out for the syncing bar at the top of your homepage. 

(Image credit: Grace Walsh/Future)

Here's what to do if you encounter issues when trying to sync your Fitbit:

  • Charge your tracker.
  • Restart your tracker.
  • Ensure Bluetooth and location services are turned on.
  • Ensure the software on your mobile device is up to date.
  • If you are using a Windows computer, uninstall any old Fitbit Connect software and install the Fitbit app for Windows 10.
  • Disconnect any other devices using your Bluetooth connection.
  • If you are using a computer without Bluetooth, plug in your wireless sync dongle.
  • Turn 'Always Connected' option on to enhance Bluetooth connectivity.
  • Turn 'All-Day Sync' on.
  • Check for known issues with your device and/or software updates.

How to get the most out of your Fitbit 

Now you know exactly what is a Fitbit, how it works and how to set it up, it's time to get started! Here are three ways you can get the most out of your fitness tracker. 

  • Wear your tracker when you sleep: As noted, the sleep tracking features on all the Fitbits are some of the best for gaining further insights into your resting habits. To make the most of these, wear your Fitbit to sleep and when you wake up in the morning, check your stats and compare them with how you're feeling. Woke up a little lethargic? Might be time to learn how to sleep better.
  • Add Fitbit friends: By adding Friends via the Fitbit App, you can track the progress of your family and friends, and message them with words of encouragement when they are close to hitting their goals. To add Friends click '+' icon on the Fitbit app dashboard, then tapping or clicking 'Add Friends'. Follow the on-screen instructions to add stored contacts and Facebook friends, or send email invitations. You can choose what data to share with them by changing your privacy settings. Competitive? The app will “rank” you and your contacts, based on the number of steps you have each taken in the past seven days.
  • Take on a Fitbit Challenge: Whether you have your own personal challenge, or team up with friends to hit a target together, a Fitbit challenge is a great way to set yourself a goal and monitor your progress as you work towards it. You can create your own challenges or add friends to Fitbit's pre-made ones - such as the Daily Showdown - for a face-off of who can take the most steps in a day. On the Fitbit App, click "Discover" and explore the range of challenges and adventures on offer. 
  • Invest in Fitbit Premium: Once you've explored what the Fitbit app has to offer, you can take your learning to the next level by joining Fitbit Premium. The subscription service will open up new workouts and challenges for you to take part in, provide more detailed health and wellness reports with extra sleep features, and guided programs to help with your nutrition. 
Grace Walsh
Health Channel Editor

Grace Walsh is woman&home's Health Channel Editor, working across the areas of fitness, nutrition, sleep, mental health, relationships, and sex. In 2024, she will be taking on her second marathon in Rome, cycling from Manchester to London (350km) for charity, and qualifying as a certified personal trainer.


A digital journalist with over six years experience as a writer and editor for UK publications, Grace has covered (almost) everything in the world of health and wellbeing with bylines in Cosmopolitan, Red, The i Paper, GoodtoKnow, and more. 

With contributions from