Teen, the coach in the app
How did I sleep? Why is my recovery low? What should I train today? Am I hitting my protein? One sentence every morning on the home screen, written from last night, and a chat that has your numbers in front of it.
Your health. Your data. Your life.
Sixteen connects to the Apple Watch or WHOOP strap you already own. It tracks sleep, recovery, HRV, strain, nutrition and strength in one place, then earn your scroll from it. No hardware. No monthly wearable membership.
Apple Watch
Through Apple Health
WHOOP strap
Direct, no membership
5:204G46
Today 6
59%Sleep
Sleep 60%Recovery
Recovery 6.5
Strain Strain is light at 6.5
Your body can take 9.3 to 13.3 today. A 20 minute walk or a short lift closes mo…
Activity
Food
Journal
Scroll
Stress
Today's stress
Last updated at 5:19 PM
2.9Highest
0.3Lowest
1.3Average
1.4
Ask Teen anything5:215G46
SEP 14 TO SEP 15
Wind Down
Heart rate variability5154
Resting heart rate5356
Respiratory rate--18.2
Sleep performance59%61%
Today vs. last 14 days
Weekly Trends
5:205G46
SEP 14 TO SEP 15
59%Sleep
Sleep Schedule
Hours vs. need59%
Sleep consistency0%
Sleep efficiency--
High sleep stress7%
PoorSufficientOptimal
Last Night's SleepLast night vs. your prior nights
EDIT Sleep like you mean it.
Sleep like you mean it.
Your sleep score is hours against your own need, consistency, efficiency and stress, in one number you can act on before bed.
Wake up to your sleep score. Hours against your own need, bedtime consistency, efficiency and overnight stress, from the Apple Watch or WHOOP strap you already wear to bed.
Learn more about sleep trackingA moving need, not a flat eight hours.
Tonight's need is yours. It comes from your baseline, your recent sleep debt and the strain you carried today. The score is how much of it you got.
Lock the apps that push bedtime back. Set a sleep schedule and the apps you chose close for the whole night. Last thing before bed stops being a feed.
Learn more about screen timeKnow before you go.
Know before you go.
Recovery is your body measured against your own baseline, never against a stranger's.
Get a daily recovery score. HRV, resting heart rate and breathing against your rolling baseline, capped by last night's sleep, recent load and your journal.
Learn more about recovery
Watch stress through the day. Between workouts, heart rate and HRV become a 0 to 3 stress line. When it runs high, Relax is one tap away. When it sags, Energize.
HRV with a normal band. Overnight rMSSD with a smallest worthwhile change, so a 4 ms dip reads as noise and a 12 ms drop reads as real.
Learn more about HRVNothing gets counted twice.
Capped, not stacked. Sleep, training load and your journal each set a ceiling on the score. Great vitals on five hours of sleep do not make a 90% morning.
Train to a number, not a feeling.
Train to a number, not a feeling.
Day strain is time in each heart rate zone plus what you lifted, with a target set by how you recovered.
See your strain build through the day. Heart rate zones 1 to 3 and 4 to 5 tracked all day from your watch or strap, with the harder zones weighted more.
Learn more about strain
Log sets in three taps. Weight and reps per set, a rest timer, progression per lift, and a load number that feeds tomorrow's recovery.
Learn more about strength
Track runs, walks and rides with GPS. A map, laps and pace for anything outdoors. Workouts your watch recorded on its own get credited too.
Lifting counts.
Heart rate under-reads a set of squats. Logged sets add muscular load from volume and effort, so a gym day is never scored as a rest day.
Eat with the day in mind.
Eat with the day in mind.
Calories and protein against your goal, with the timing your sleep can feel.
Log food by search or photo. A large food database, or a photo when typing is too slow. Correct the guess before you save, then watch calories, protein, fat and carbs fill in.
Learn more about nutritionLate dinner, shown next to sleep stress.
Meals carry a time. So the 11pm plate sits beside the overnight heart rate it caused, and the pattern is hard to miss.
Ask Teen whether you hit your protein. A coach that has your sleep, recovery, food and screen time in front of it. Every answer comes from your own numbers.
Earn your scroll.
Earn your scroll.
Every other tracker stops at the number. Sixteen locks the apps and lets your body unlock them.
A screentime score, every day. Total time, the first app you opened and the last app before bed. The two moments that shape a day, made visible.
Learn more about screen time
Block the apps that bite. Choose apps and websites. They lock behind a shield with a friendly mascot, not a wall of shame. Some can be always allowed.
Three breaths open a ten minute window.
Then the shield comes back on its own. A walk, a workout, a logged meal or a finished task pays minutes into a bank you spend on the apps you locked.
You already own the sensor.
You already own the sensor.
Sixteen reads the Apple Watch or WHOOP strap on your wrist and anything else that writes to Apple Health. We will never sell you a second device.
Learn more about integrations
Your data stays on your phone. And only there.
Your data stays on your phone. And only there.
Scores are computed on the device. WHOOP strap data travels from the strap to your phone over Bluetooth and nowhere else. Backup is optional and off by default.
Learn more about our approach to privacyMeasure. Understand. Act. Then measure again.
A journal that explains the number
Tag alcohol, late meals, screens in bed or a hard session. Over a few weeks you see which ones cost you the most recovery, and the score stops being a mystery.
Every score, explained.
If we cannot explain a number, we do not show it. Each score has a published method: what it uses, what it needs, and what it cannot tell you. Sixteen is not a medical device and does not diagnose anything.
Our values lead the way.
Pay once. Keep access.
$99 once for lifetime access, or $19.99 a month. No wearable membership, no hardware, no free tier we would have to hide.
Learn more about pricingPrivacy. On your phone.
Scores are computed on the device. Nothing leaves it unless you turn on backup, and you can delete everything from Settings.
Learn more about privacyHonest about what it cannot do.
No accuracy claims against other brands. No diagnoses. Every integration marked live only when it works on real devices.
Learn more about our methodsQuestions people ask before they switch
What is Sixteen?
Sixteen is a health app for iPhone. It reads the wearable you already own, scores your sleep, recovery, strain and nutrition every day, logs your strength training, and uses those scores to control the apps on your phone. It costs $99 once, or $19.99 a month.
Which wearables work with Sixteen?
Apple Watch through Apple Health, and WHOOP straps directly over Bluetooth with no WHOOP membership. Any other device that writes to Apple Health, such as Oura or Garmin through their own apps, flows in the same way. Direct Oura and Garmin connections are on the roadmap.
Do I need a subscription?
No wearable membership, ever. Sixteen itself is $99 once for lifetime access, or $19.99 a month if you prefer not to commit. There is no free tier and no trial, and we say so up front.
Is Sixteen a medical device?
No. Sixteen is a fitness and habit product. It does not diagnose, treat or prevent any condition. The Science page explains exactly what each score is and is not.
Is Sixteen on Android?
Not yet. Sixteen is built for iPhone and uses Apple's Screen Time and Health frameworks.
SixteenPay once. Keep your data. Earn your scroll.
Sixteen 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.