Calibrate Guides
Practical, evidence-based guides on light and your day
Short reads on how the timing of light shapes your energy and sleep, and how to put it to work in a normal week. Grounded in circadian research, written to be useful.
Light
How much morning sunlight you need, and whenGet outside within an hour of waking if you can. Dark winter mornings need a different plan.
Light therapy lamps: how to choose one and when to use itWhat actually matters when choosing a bright-light lamp, from lux at your real sitting distance to UV filtering and size, plus how to use one for morning light.
How to dim your lights in the evening for better sleepBright overhead lights and screens late in the evening are the main things to change. Room-by-room tips.
Are LED lights bad for sleep? Why cool white bulbs tell your body it's daytimeCool white LEDs are the ones to swap in the rooms you use after dark. Warm, dim bulbs are fine.
How daytime light affects your sleep at nightMost offices are far dimmer than outdoors. Getting outside during the workday is linked to better sleep.
What different light colors at night do to your bodyHow red, amber, blue and white light at night compare for sleep.
Melanopsin: how your eyes tell your body what time it isMelanopsin is the light sensor in your eye that sets your body clock. Melanopic lux measures how much light it gets.- Is your phone keeping you up at night?A bright screen late at night can delay sleep. Dimming it and setting a stop time are likely to help more than a warm screen mode.
Do blue light glasses work?Amber or orange lenses worn in the evening help some people fall asleep sooner. Clear computer lenses filter too little to matter for sleep.
Sleep
How to fix your sleep schedule with light timingA step-by-step schedule for moving your sleep earlier or later using light and dark.
Does sleeping in on weekends make up for lost sleep?Long lie-ins on Saturday and Sunday can make Sunday night hard. You can catch up on sleep without that.- How much sleep do you need?Seven or more hours of sleep for most adults, which takes more than seven hours in bed.
Should you take melatonin?Supplements may help with a few specific problems. Long-term safety data are thin and labels are often wrong, so ask a doctor first.
Does a warm shower before bed help you sleep?It may help you fall asleep a little faster if you time it 1 to 2 hours before bed. The evidence for that timing comes from 36 patients.
How to sleep after a night shiftMost night workers' body clocks never fully switch to daytime sleep. A dark bedroom and a steady sleep block help with that.
Environment
Sunrise alarm clocks: what they do and who they helpHow a sunrise alarm simulates dawn to make waking gentler, what the research on grogginess actually shows, and who is most likely to notice a difference.
How dark should your bedroom be?How to find where light gets into your bedroom, and whether blackout curtains or an eye mask will block it.
When your partner or kids want the lights onWhat you can change on your own when others want the lights bright, and how to ask for the one change that matters most to you.
Energy
Why you get tired in the afternoonMost people get sleepy in the early afternoon. Short sleep and late coffee can make it worse.
Do you need to wait 90 minutes before morning coffee?No trial has tested the 90-minute coffee wait. For sleep, the time of your last cup matters more.
How to nap without ruining your nightNap 8 to 10 hours before bed, in a dark room, with an alarm set for 40 minutes at most.
Timing
- How to adjust when the clocks changeClocks go back on October 25 in the UK and EU and on November 1 in the US. They go forward again in March.
- Are you a night owl or an early bird?Some people are built to run late, and evening light can push anyone later. How to tell which applies to you, and how to live with it.
Does working out at night hurt your sleep?Most healthy people can work out in the evening and sleep fine. A hard session that ends right before bed is the exception.
Does when you eat affect your sleep and energy?Stop eating 2 to 3 hours before bed and eat most of your food earlier in the day. Light still sets the timing of your sleep.
How to get over jet lag fasterFlying east is harder than flying west, and the right hours for daylight depend on how many time zones you cross.
Tools
- Caffeine cutoff calculatorYour last caffeine before bed.
- Clock change plannerSleep and light when the clocks change.
- Chronotype quizEarly, late, or in between?
- Social jetlag calculatorHow far sleep moves on days off.
- Morning light plannerOutdoor light after sunrise.
- Jet lag plannerSleep and light, day by day.
- Night shift sleep plannerSleep and light around shifts.
- Light therapy lamp distance calculatorLight reaching you, and for how long.
Ready to make it your own?
Calibrate turns these ideas into a daily light-timing plan built around your real schedule and light access. No wearable required.