Wane 3.0 · Method

How Wane works

Updated October 24, 2026. This page replaces our earlier white paper, which described the 2.x score.

1. The battery

Wane shows one number: how much you have left right now, from 0 to 100. Behind it are two ideas:

• Capacity — how full you can start the day. It changes over days, mostly with sleep.
• Charge — how much is left now. It moves through the day, from your capacity toward bedtime.

In short: charge = capacity × alertness at this hour − today's load + what Wane has learned about this hour from you, kept between 0 and 100. The whole calculation runs on your iPhone, in the app and in the widgets. The same inputs always give the same curve.

2. The shape of your day

The curve's shape comes from the two-process model of sleep regulation, first described by Borbély in 1982:

• Sleep pressure (Process S) builds while you are awake and drains while you sleep. Wane uses the build-up and drain time constants (18.2 h and 4.2 h) published by Daan, Beersma and Borbély (1984).
• The body clock (Process C) lifts and lowers alertness across 24 hours. Wane uses a 24-hour wave with a 12-hour harmonic, a shape that follows Folkard and Åkerstedt's model of alertness (1987). It is anchored to the middle of your usual sleep, and it produces the familiar early-afternoon dip. The amplitudes and timing are Wane defaults.
• Grogginess after waking (sleep inertia) is a short dip that clears within the first hour or so. Its depth and duration are Wane defaults.

Wane needs to know when you usually wake and sleep. With only an iPhone, it uses the hours you set once. If Apple Health has your sleep — from an Apple Watch or another app — Wane uses the real nights instead. A connected Oura Ring or Whoop fills the nights Apple Health does not have. Overlapping sleep is counted once.

3. How full you start

Capacity starts at 100 and is lowered by recent short sleep:

• Sleep debt. For each of the last 7 nights, Wane takes the hours you slept below your need (8 hours by default). Recent nights count more: last night counts fully, and the weight falls to 0.2 for a night a week ago. Each weighted hour of debt lowers capacity by 6 points, down to a floor of 40. A night with no data counts as unknown, not as short sleep.
• Heart rate variability. If a watch or ring provides it and it sits below your own recent baseline, capacity is lowered by up to 15%.
• The longer trend. If you have an account, our server also works out a daily score from your health summaries — heart rate variability, sleep, resting heart rate and recovery, each compared with your own recent baseline. That score caps how full your morning can start: at most 100 minus half the score, so it only bites when the score is high. This cap is softened on purpose, so a hard few weeks lowers the morning without flattening the whole day.

All of these numbers are Wane defaults.

4. What drains it faster

• Meetings (Wane Premium, optional). With calendar access, every minute of meetings takes 0.05 points from the rest of the day once it has happened, up to 20 points in a day. Overlapping meetings count twice. The calendar is read on your iPhone. Event titles and times never leave it.
• Hard exertion. Once the active energy you have burned today passes 400 kcal, each further kcal takes 0.02 points, up to 10 points. Light walking is not load.

Each term has a cap so that no single input dominates the day. These numbers are Wane defaults.

5. Learning from your taps

The model is a first guess, and the app says so: the first days are labelled as learning. You teach it with one tap — full, OK, low or empty — from a widget, the app, Control Center, the Action button or Siri.

• Each level stands for a charge: full 90, OK 65, low 35, empty 10.
• Today: the tap moves the rest of today's curve toward what you said, by at most 20 points. That holds until the end of the day. Tomorrow starts clean.
• Tomorrow and after: the day is split into eight 3-hour stretches. Each tap moves its stretch's learned correction 30% of the way toward what you said. Corrections are capped at ±25 points and blended between stretches, so the curve never has steps.
• Taps within 5 minutes of each other count as one answer, so a quick correction ("low… no, OK") teaches once.

6. Wane Check

Wane Check is five short interactive tests, 25 to 90 seconds each: The light, The digits, The pairs, The grid and The hands. They read your reactions in the moment, with no wearable.

• Against your own usual. Each result is compared with your own past runs of the same test, on the same phone, at the same time of day — once there are 5 earlier runs to compare with. Until then it is compared with a typical run, and the app says it is still learning your usual.
• Phone timing. Reaction times are timed from the frame the stimulus appears on, and part of the device key is the screen's refresh rate, so a 60 Hz run is never compared with a 120 Hz baseline.
• Effect on the battery. A result moves today's battery a little. It does not change what Wane has learned from your taps.

Wane Check is not a medical or cognitive assessment.

7. Actions

When the battery is below 45%, Wane offers one thing to do now, picked from a short fixed list by the time of day and your sleep: ten minutes outside, five minutes off screens, three minutes of slow breathing, water and a stand, a 20-minute nap (only before 15:00, and only after a short night), or protecting the evening (only after 19:00).

• Each comes with a small estimate, always shown with "~" (2 to 8 points). These estimates are Wane defaults, kept deliberately small, and are never added to your curve.
• Wane Premium ranks actions by what helped you: after you mark an action done, your next tap within 90 minutes is compared with what the curve expected. An action needs 3 such measurements before its own effect replaces the default order.

8. What we do not claim

• Wane has not been validated in a clinical trial. We publish no accuracy figure.
• Wane does not diagnose, treat or prevent any condition, including burnout. It is not a medical device.
• The battery is an estimate of how your day is going, built from behavioural signals and sleep. It is not a measurement of your body's energy.
• Unless a reference is given, the numbers on this page are Wane defaults that we may change as we learn. When we change one, we update this page.

If you are struggling, talk to a doctor.

9. References

1. Borbély AA. A two process model of sleep regulation. Human Neurobiology. 1982;1(3):195–204.
2. Daan S, Beersma DGM, Borbély AA. Timing of human sleep: recovery process gated by a circadian pacemaker. American Journal of Physiology. 1984;246(2 Pt 2):R161–R183.
3. Folkard S, Åkerstedt T. Towards a model for the prediction of alertness and/or fatigue on different sleep/wake schedules. In: Oginski A, Pokorski J, Rutenfranz J, eds. Contemporary Advances in Shiftwork Research. Kraków: Medical Academy; 1987:231–240.