Fitness Trackers: What to Buy, and What They Actually Measure

I run DirJournal, and we have had a "best fitness trackers" post on the site since 2020. Every device in it is now discontinued, which is the nature of this category. So I rebuilt it, and while I was at it I added the part these roundups almost always leave out: how accurate the numbers on your wrist actually are.

That matters more than the ranking. You can buy any well-reviewed tracker and be fine. What trips people up is trusting the data more than it deserves, and missing the subscription fees stapled to the cheap sticker price. Both are below, with the current picks.

What a Fitness Tracker Measures Well, and What It Does Not

Start here, because it should shape what you buy and how you use it.

In 2017, researchers at Stanford tested seven wrist trackers against laboratory equipment across 60 people of different sizes and fitness levels. Six of the seven measured heart rate within a 5% error, which is good. None measured energy expenditure (calorie burn) within an acceptable range. The most accurate device was off by an average of 27%. The least accurate was off by 93%. The lead researcher noted that a usable error rate outside a medical setting should be under 10%, and no device cleared that bar for calories.

Newer devices have better heart-rate sensors, but the calorie problem has not been solved, because it is a hard estimation problem, not a sensor problem. Your tracker sees motion and pulse, then a proprietary algorithm guesses your energy burn. Two people of the same age, weight, and height running side by side will get the same estimate and burn different amounts. The Stanford team also found errors were larger for people with higher body mass, for men, and for people with darker skin tones, because the optical sensors that read blood flow through the skin perform unevenly. That last point rarely makes it into a buying guide and it should.

Here is the honest version of what you are paying for:

The practical takeaway: a tracker is excellent at one job, getting you to move more. People wear one and become noticeably more active. Use it for that and for trends, not for precise calorie math.

The Current Picks, by Who You Are

Prices are typical United States retail and move often, especially on sale. Check the live price before buying.

Best for Most People: Fitbit Charge 6 (around $160)

The Charge 6 is the tracker most testing sites still rank first, and it is the one I would hand a friend who just wants a good band without thinking hard. Accurate heart-rate sensor, strong sleep reports, built-in GPS, and a few smart touches like Google Maps, YouTube Music, and Google Wallet. Two caveats: Google has steadily stripped features from Fitbit (it removed Google Assistant support), and the deeper insights sit behind Google Health Premium, about $100 a year. Released in 2023, still the flagship, often discounted below $130.

Best Value: Xiaomi Smart Band 9 (around $40)

If you want most of the function for a fraction of the price, this is it. A large, bright AMOLED screen, heart rate, sleep, and a battery that runs roughly 18 days per charge. No built-in GPS and the health analysis is basic, but at this price those are easy trades. The Amazfit Band 7 (around $50 to $60) is a close alternative with similar battery life and onboard workout modes.

Best Fitbit on a Budget: Fitbit Inspire 3 (around $100)

The cheapest current Fitbit, with a 10-day battery, heart rate, sleep, and the polished Fitbit app. The screen is a small monochrome strip and, like the Charge 6, the best insights want a Premium subscription. Worth it mainly if you specifically want the Fitbit ecosystem.

Best Without a Subscription: Huawei Watch Fit 4

The feature-per-dollar standout in recent testing. Bright AMOLED display, dual-frequency GPS, offline maps, and solid heart-rate and sleep tracking, with no mandatory subscription to unlock the data. The trade-offs are limited third-party apps and patchy contactless payment, and availability in the United States is inconsistent, so confirm you can buy it and get support where you live.

Best for Kids: Fitbit Ace LTE (around $135 to $230) or Garmin Vivofit Jr. 3 (around $70)

Two very different answers. The Ace LTE is effectively a kid-focused smartwatch with calling, messaging, and GPS, but it needs the Ace Pass subscription (about $10 a month) and the battery lasts roughly a day. For a younger child, or if you do not want fees and nightly charging, the Garmin Vivofit Jr. 3 is simpler and tougher: it is swim-friendly, runs about a year on a replaceable battery, and uses chores-and-rewards features to get kids moving. The older Fitbit Ace 3 (around $80) also still sells.

Best for Swimmers and Casual Gym Use: a 5ATM Fitbit or Garmin

Look for a 5ATM water-resistance rating, which covers pool swimming. Most current Fitbit bands and Garmin trackers carry it. For structured training and recovery metrics, Garmin's Vivoactive 6 (around $300) steps up to a more watch-like device, though at that price you are crossing into smartwatch territory.

Worth Knowing: the Screenless and Ring Options

The category has widened. Screenless straps and smart rings (the Oura ring, the Whoop-style bands, the new Fitbit Air at $99.99) track recovery, sleep, and strain without a display. They suit people who want the data without a screen on their wrist, and they lean even harder on trends over single readings.