What the subscriptions in this category actually cost you
Three makers charge, and they charge in three different ways. Knowing which is which is the whole point of this page, so here it is plainly, from each company’s own wording.
Oura is the strictest. Oura’s own membership page states that without an active membership the app shows only the three daily scores and basic settings. That is not a reduced feature set — it is the detail behind your sleep, readiness and activity scores disappearing while the hardware on your finger keeps working. The Oura Ring 4 and Ring 5 are, on published sensors, the best sleep trackers we cover. They are also a subscription product with a ring attached, and anyone who has not priced the membership over three years has not priced the purchase.
WHOOP does not pretend otherwise: there is no hardware-only option. The WHOOP One listing is a 12-month membership that ships a WHOOP 5.0, which is exactly how our registry entry, its page copy and its FAQ describe it. If you want WHOOP, you are buying a subscription. That is a clear, honest model — it is simply not what this page is for.
Google (Fitbit) sits in the middle. Google rebranded Fitbit Premium as Google Health Premium, and the deeper coaching and some insights sit behind that paid tier while basic sleep tracking does not. In practice that means a Fitbit device gives you a sleep score and stages for free and reserves the interpretation for subscribers. Reasonable, but it is why no Fitbit is a pick on this page.
For contrast, Garmin states that all existing features and data in Garmin Connect remain free, positioning Connect+ as an addition rather than a gate, and Samsung, RingConn, Amazfit, Withings and Xiaomi all publish no subscription for their sleep data at all.
Pick the form factor before you pick the device
If you want the most night data and no fee: upper arm
The Garmin Index Sleep Monitor is the only device we cover built for nothing but sleep. It sits on the upper arm rather than the wrist, which is where a sensor gets the cleanest signal and where it is least likely to annoy you, and it has no screen. Garmin publishes up to seven nights per charge with Pulse Ox on, a 5 ATM water rating in the owner’s manual, two band sizes (S-M at 12.8 in and L-XL at 17.8 in), and a smart wake alarm that vibrates in a lighter sleep stage inside a window you choose.
The honest limitation is in the name: it is a night device. It does not track your day, it does not show you the time, and if you already wear a Garmin watch, its real pitch is that you can take the watch off at bedtime and still get the overnight data. Garmin publishes no weight for it, which we print as a gap rather than filling in.
If you want 24/7 tracking and no fee: a ring
The RingConn Gen 2 is the subscription-free answer to Oura and the reason this page can recommend a ring at all. RingConn publishes 10 to 12 days of battery depending on size, a charging case that holds 150-plus days of top-ups, a 100 m water rating, about 2 g of weight, a 12-month warranty, and a tracking set covering sleep, sleep apnea (AHI), activity, stress, heart rate, HRV and SpO2 — with the full app feature set included with the ring. For a traveller who hates carrying chargers, the case alone is an argument.
The Samsung Galaxy Ring is the other no-fee ring and the pick if you are already inside Samsung’s ecosystem: up to seven days of battery, 10 ATM plus IP68, heart rate, SpO2 and skin temperature, with the data living in free Samsung Health. It is at its best paired with a Galaxy phone, which is the constraint rather than a flaw. Both rings need sizing before purchase — RingConn recommends a sizing kit, and getting this wrong is the most common way a ring purchase goes bad. We go deeper on the whole category in best smart rings and compare the two leading rings in Oura Ring vs Galaxy Ring.
If you will not wear anything to bed: the mat
The Withings Sleep Tracking Mat is the outlier here and for a certain reader it is the only acceptable answer. It goes under the mattress, so there is nothing on your body at all. It is USB-powered, which means it never needs charging — a property no wearable on this page can match — it auto-syncs over Wi-Fi to the free Health Mate app, and it tracks sleep cycles, heart rate and snore detection with no subscription.
Two honest limits. It only knows about you when you are in that bed, so a night in a hotel is a night with no data; and because it senses through a mattress rather than from skin, it cannot offer the SpO2, skin-temperature and HRV detail the wearables here do. Withings’ own app listing names subscriptions — Withings+ and a paid cardiologist ECG review — but neither is needed to read your own data.
If you want a WHOOP-shaped band without the WHOOP bill
The Amazfit Helio Strap is the closest thing to a screenless WHOOP band that does not carry a membership. Amazfit publishes up to 10 days of typical use from a 232 mAh cell with a charge time under an hour, a 5 ATM water rating, wear on the wrist (145–205 mm) or on the upper arm with the arm band, and a night report covering sleep stages including REM, naps, sleep schedule, sleep breathing quality, a sleep score and sleep HRV. The Zepp app is free and syncs to Apple Health, Google Fit and Strava.
The Xiaomi Smart Band 10 is the budget option and is on this page because it is genuinely usable rather than merely cheap: Xiaomi publishes up to 21 days of battery, a 1.72 in AMOLED at 1,500 nits, and sleep stages with sleep-quality analysis, for roughly the price of a pair of cheap headphones. The caveats are real — no onboard GPS, no published water rating, and the Xiaomi Fit app is metric-only — but nothing is paywalled.
What none of these do
Every device here estimates sleep from movement, heart signals and, in the mat’s case, pressure. None of them measures sleep the way a clinical study does, and the clinical review we cite finds consumer devices reasonable at total sleep time and much weaker at staging it. The Cleveland Clinic is worth reading on the broader point, which is that watching your sleep data closely can itself make sleep worse.
Use them for trends. Bedtime consistency, total time asleep, and how your resting heart rate and HRV drift across a week are the outputs that justify the purchase. A single night’s stage breakdown is not worth a decision. And where a device reports something like an AHI figure or flags breathing irregularities, treat that as a prompt to speak to a clinician — we are a fitness publisher, these are wellness devices rather than diagnostic ones, and nothing on this page should be read as medical advice.
So which one?
Most night data, no fee: Garmin Index Sleep Monitor. One device for day and night, no fee: RingConn Gen 2, or the Samsung Galaxy Ring if you carry a Galaxy phone. Nothing on your body: the Withings Sleep Tracking Mat. A screenless band: the Amazfit Helio Strap. Spending as little as possible:the Xiaomi Smart Band 10. And if after all that you still want the Oura, buy it with the membership priced in over three years rather than as an afterthought — on sensors it earns its reputation, and our main sleep tracker roundup says so.
