No subscription
The two best known sleep trackers both charge a membership. You do not need one. Here is what tracks sleep well without a plan, and what turns the data into a better night.
Sleep is where memberships are hardest to justify. The sensors are the same across brands, and the science of a sleep score is not secret: duration against need, timing, efficiency and how hard the body worked overnight. The paid part should be the software that helps you change it.
Good: Sleep stages, duration, overnight heart rate, HRV and respiratory rate, plus a sleep score on recent watchOS.
The catch: No sleep need model, no consistency coaching, nothing that guards your bedtime.
Good: Sleep score with stages, overnight HRV on supported watches.
The catch: Insight without action. Nothing changes your evening.
Good: A score from hours versus need, consistency, efficiency and sleep stress, from Apple Watch or a WHOOP strap, with a bedtime lock that keeps the apps out of your night.
The catch: iPhone only. Needs a wearable worn to bed.
How to judge any of them
Your sleep need moves with debt and strain. A score against a fixed number is a guess.
Bedtime drift affects how you feel more than most people expect. It should be scored.
A tracker that can lock the apps that keep you up is worth more than one that only reports the damage.
Keep reading
SixteenSixteen is $99 once for lifetime access, or $19.99 a month. Connect the wearable you already own. No hardware to buy, no membership that expires.
iPhone (iOS 17 or later). Prices in USD.