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Restadian tool

Circadian Schedule Planner

A seven-day schedule for sleep opportunity, morning light, evening wind-down, and gradual time shifts, built around the week you have.

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The tool

Build your seven days

Give the planner the week you have rather than the week you want, and it will lay out the sleep opportunity, the light, the caffeine and the exercise around your own wake time. Every time it shows you is measured from when you wake, because that is the anchor you can hold.

This is a suggested schedule, not a prescription and not a diagnosis. It cannot measure your body clock, and it cannot identify, confirm or rule out a circadian rhythm sleep-wake disorder. If your timing is far enough out of step to affect your work, your safety or your health, take that to a clinician rather than to a planner.

The form below runs in your browser, so it needs JavaScript to work. The published method further down this page does not need one, and it is the part worth reading first.

The wake time you keep

Both of these anchor the whole plan, so answer for an ordinary day rather than a good one.

What actually happens, alarm and all.

Repeat the time above if you are holding steady rather than moving.

A rough figure is fine. Nobody publishes a maximum, and this planner will not invent one.

The bedtime you keep

Both ends of the range you actually turn in at. Enter the same time twice if it barely moves.

The hours you do not control

Leave any of these blank. The planner uses them to say where the schedule and your week disagree, and it says so plainly rather than quietly moving a window.

Caffeine and exercise

Optional, and useful. Both have a cited timing figure attached, and both are named in the results only when you fill them in.

The one timing the evidence flags is a hard session finishing within an hour of bed. Everything gentler was found not to harm sleep.

How you would describe your own timing, and how fast to move

Your own read frames the plan. It never becomes a category, a type or a score.

Left to yourself, you are

Capped at sixty. The CDC describes one hour a day over two or three days as the pre-travel step, and this planner treats it as the largest step worth attempting.

Daylight where you are

Optional. The sun’s position is arithmetic and your device can do it, so nothing you type here is sent anywhere. The planner uses it for one thing: to say whether your morning window contains any daylight at this time of year. Give it the place you actually are, because it reads the rest from your device’s own clock.

Where what you type goes

Nowhere. Everything above runs in this browser, on this device. Restadian never receives what you enter, because nothing here sends it anywhere.

What this tool will not tell you, and why

  • How many minutes of morning light. The direction is well established. Light after your circadian nadir pushes your clock earlier. The duration is not. The AASM practice parameters say in as many words that the "optimal timing, duration, and dosing of morning light treatment … remain to be determined", and the 2015 guideline declines to recommend post-waking light on its own for adults at all. So the planner marks when the window opens and says nothing about how long to stand in it.Morgenthaler et al., Practice parameters for the clinical evaluation and treatment of circadian rhythm sleep disorders · Auger et al., Clinical practice guideline for the treatment of intrinsic circadian rhythm sleep-wake disorders
  • How far before bed to bring the light down. Evening light delays the clock, and ordinary room lighting is enough to do it, and the study that showed this ran across the whole eight hours before bed. Nobody has turned that into a number of minutes you should dim for. The planner opens the evening window where your own sleep opportunity opens, which is a boundary the duration recommendation already gives it, and does not dress the width up as a finding.Gooley et al., Exposure to room light before bedtime suppresses melatonin onset and shortens melatonin duration in humans · Watson et al., Recommended Amount of Sleep for a Healthy Adult
  • A maximum acceptable night-to-night variation in sleep timing. The National Sleep Foundation panel that reviewed this agreed consistency matters and published no number for how much movement is too much. The metrics that describe regularity are defined differently and do not always agree with each other. The Regularity Report describes your spread and refuses to grade it.

Every number above, and where it came from

Each figure this tool uses is registered in the code with the sentence it was taken from. Open one and you can check the number against the source without taking our word for it.

  1. Watson et al., Recommended Amount of Sleep for a Healthy AdultAmerican Academy of Sleep Medicine & Sleep Research Society · 2015
    The sentence the figure came from
    Adults should sleep 7 or more hours per night on a regular basis to promote optimal health. Sleeping more than 9 hours per night on a regular basis may be appropriate for young adults, individuals recovering from sleep debt, and individuals with illnesses.
  2. Riedy & Williams, Jet Lag Disorder, CDC Yellow BookCenters for Disease Control and Prevention · 2026
    The sentence the figure came from
    an average rate of adaptation of 1.5 hrs/day for westward travel and 1 hr/day for eastward travel … Exposure to bright light in the morning following the circadian nadir (approximately 2–4 hours prior to habitual wake time) promotes phase advances … exposure in the evening generally promotes phase delays … For short trips (e.g. less than 2 days), avoid adapting … Shifting sleep 1 hour later (for westward travel) or earlier (for eastward travel) per day in the 2–3 days prior to the trip may reduce the amount of time required to adjust … Short daytime naps (20–30 minutes) can be utilized to help sustain alertness during the local day, while longer daytime naps may interfere with subsequent nighttime sleep.
  3. Khalsa et al., A phase response curve to single bright light pulses in human subjectsThe Journal of Physiology · 2003
    The sentence the figure came from
    A relatively rapid transition from phase delays to phase advances occurs near circadian phase 0 h [the core body temperature minimum] … peak-to-trough amplitude of 5.02 h … phase delays up to −3.60 h and phase advances up to +2.01 h.
  4. Eastman & Burgess, How to travel the world without jet lagSleep Medicine Clinics · 2009
    The sentence the figure came from
    bright light can help produce phase advances when applied late in the sleep episode and in the morning after the Tmin, and can help produce phase delays when applied early in the sleep episode before the Tmin … Bright light is avoided after waking … because it could coincide with the phase advance portion of the light PRC … When the circadian clock phase shifts in the opposite direction to the shift in the LD cycle and sleep/wake schedule, this is considered re-entrainment in the “wrong” direction (antidromic re-entrainment) … phase advance the circadian clock for crossing up to 7 time zones east and phase delay the clock for crossing 8 or more time zone east.
  5. Sack et al., Circadian rhythm sleep disorders: part I — AASM reviewSleep · 2007
    The sentence the figure came from
    Exposure to the morning light after an eastward flight of more than eight time zones could retard adaptation to local time because it would be “hitting” the wrong area of the light PRC. Likewise, late evening light following a westward flight could retard adaptation for the same reason … The circadian system is most sensitive to light during the biological night, when humans normally sleep, and is least sensitive to light about midday.
  6. Gooley et al., Exposure to room light before bedtime suppresses melatonin onset and shortens melatonin duration in humansJournal of Clinical Endocrinology & Metabolism · 2011
    The sentence the figure came from
    exposure to room light in the 8 h preceding bedtime … exposure to room light suppressed melatonin by greater than 50% in most (85%) trials … melatonin levels were strongly suppressed by room light (by about 70%) before bedtime … exposure to room light before bedtime shortened melatonin duration by about 90 min compared with exposure to dim light. Room light was defined as less than 200 lux and dim light as less than 3 lux.
  7. Morgenthaler et al., Practice parameters for the clinical evaluation and treatment of circadian rhythm sleep disordersAmerican Academy of Sleep Medicine / Sleep · 2007
    The sentence the figure came from
    Timed light exposure in the work environment and light restriction in the morning, when feasible, is indicated to decrease sleepiness and improve alertness during night shift work … Morning light exposure is indicated in the treatment of DSPD. Optimal timing, duration, and dosing of morning light treatment for DSPD remain to be determined.
  8. Auger et al., Clinical practice guideline for the treatment of intrinsic circadian rhythm sleep-wake disordersJournal of Clinical Sleep Medicine · 2015
    The sentence the figure came from
    There is insufficient evidence to support efficacy of post-awakening light therapy (monotherapy) as a treatment for DSWPD (versus no treatment). No recommendation.
  9. Drake et al., Caffeine effects on sleep taken 0, 3, or 6 hours before going to bedJournal of Clinical Sleep Medicine · 2013
    The sentence the figure came from
    The magnitude of reduction in total sleep time suggests that caffeine taken 6 hours before bedtime has important disruptive effects on sleep and provides empirical support for sleep hygiene recommendations to refrain from substantial caffeine use for a minimum of 6 hours prior to bedtime.
  10. Stutz, Eiholzer & Spengler, Effects of evening exercise on sleep in healthy participantsSports Medicine · 2019
    The sentence the figure came from
    the studies reviewed here do not support the hypothesis that evening exercise negatively affects sleep … sleep-onset latency, total sleep time, and [sleep efficiency] might be impaired after vigorous exercise ending ≤ 1 h before bedtime.
  11. Chaput et al., The importance of sleep regularity — National Sleep Foundation consensus statementSleep Health · 2023
    The sentence the figure came from
    Consistency of sleep onset and offset timing is important for health, safety, and performance. Nonetheless, when insufficient sleep is obtained during the week/work days, weekend/non-work day catch-up sleep may be beneficial.
  12. Czeisler et al., Stability, precision, and near-24-hour period of the human circadian pacemakerScience · 1999
    The sentence the figure came from
    the intrinsic period of the human circadian pacemaker averages 24.18 hours in both age groups, with a tight distribution consistent with other species.
The method

What it measures, what it assumes, and where that breaks down

What it measures

Nothing, in the strict sense. The planner does not measure your circadian phase. That requires assays this site has no access to. It estimates a plausible position for your internal clock from the timing you report, and then arranges the controllable parts of your day around that estimate.

The distinction matters, and the tool keeps making it. An estimate built from your own reported wake times is a reasonable planning assumption. It is not a measurement, and it is never presented as one.

What it asks you for

  • Your usual wake time, and how much it varies across a week.
  • The hours you need to be working or available.
  • Roughly where you are, so daylight timing can be approximated.
  • How much daylight your mornings realistically contain, not how much you would like them to.
  • When you drink caffeine and when you exercise.
  • What your evenings are committed to.

It needs an honest picture of an ordinary week, not an ideal one. A plan built on the week you wish you had will fail in the first three days.

What it gives back

A seven-day schedule marking four things per day: when the sleep opportunity opens and closes, when to prioritise getting light, when to bring the light level down, and, if you are moving your timing rather than holding it, where the next incremental step sits.

Every time is written as a distance from your own wake time first, with the clock reading underneath it. A clock hour on its own reads as a prescription, and the planner has no business issuing one.

Shifts are staged rather than jumped. Where the plan asks you to move, it shows the intermediate days rather than only the destination.

The assumptions it rests on

These are the load-bearing ones, stated so you can judge whether they hold for you.

  1. Your reported wake time approximates your clock’s morning. For most people on a settled schedule this is reasonable. For someone whose schedule has recently changed, or who wakes by alarm far earlier than they otherwise would, it is weaker.
  2. Light is the dominant timing signal. The plan prioritises light over meal timing and exercise timing, because the mechanism is better described.
  3. Gradual shifts are more sustainable than abrupt ones. This is a practical assumption as much as a physiological one: plans people can follow beat plans they abandon.
  4. You are on a day-oriented schedule. If you are not, the Shift-Work Planner is the right tool; this one’s assumptions will not hold.

Where the numbers come from, and where they stop

The staged shift is capped at one hour a day. That is the pre-travel step the CDC describes, and the planner treats it as the largest step worth attempting rather than a target: you choose the size, and it refuses anything larger.

Two widths are nobody’s to publish yet. The planner names both under the tool rather than filling either one in.

  • How long to stand in the morning light. The AASM practice parameters say in as many words that the optimal timing, duration and dosing of morning light treatment remain to be determined, and the 2015 guideline declines to recommend post-waking light on its own for adults. So the window opens as you wake and closes at the middle of your waking day, where the AASM review says your clock is least sensitive to light. Neither boundary is a dose.
  • How far before bed to bring the light down. Ordinary room light, under 200 lux rather than a screen, suppressed melatonin by about 70% across the eight hours before bed. Nobody has turned that into a number of minutes to dim for. The evening window opens where your own sleep opportunity opens, which is a boundary the duration recommendation already gives it.

Every other figure the planner prints is registered in the code with the sentence it was taken from, and listed under the tool with a link you can open.

What it does not do

  • It does not diagnose. No output states or implies that you have a circadian rhythm sleep–wake disorder, delayed or advanced sleep phase, or any other condition. There is no field in the plan a label could live in.
  • It gives no medication or supplement guidance of any kind.
  • It does not tell you how many hours you should sleep.
  • It does not score your schedule or rank you against a population.

Limitations

It cannot see how bright your mornings are, how well you slept last night, or whether your late evenings are a choice or an obligation. It infers everything from what you type, and the inference is only as good as the input. The daylight check is the one exception, and it only answers whether the sun is up, not whether any of it reaches you.

It also cannot tell you whether timing is your problem at all. A schedule that looks sensible on paper and still does not work is genuinely useful information, and it is a reason to speak to someone, not a reason to re-run the planner with different numbers.