Circadian: Your Natural Rhythm

Natural Cycles

In-app purchases

About this app

🌟 OPTIMIZE YOUR NATURAL CYCLES & BIORHYTHMS TO RISE, SLEEP, THINK, AND EAT AT IDEAL TIMES
Do you ever feel out of sync with your natural cycles? Circadian is the leading circadian rhythm app. By tuning into your circadian rhythm and honoring your biorhythms, you enjoy better sleep, balanced hormones, and a healthier lifestyle.

☀️ ALIGN WITH SUNLIGHT & SEASONS
Why dissect every sleep cycle or follow a fixed sleep calendar when natural cycles guide you best? This circadian rhythm app harnesses diurnal patterns—risen dawn, UVA/UVB rise & set, solar noon, sunset, and darkness—to set consistent rise & sleep reminders and wind-down alerts. Trust your internal clock to help you establish a smooth sleep rhythm and a natural circadian sleep pattern.

🛏️ BEDTIME CALCULATOR & BIORHYTHM CALCULATOR
Plan your optimal hours of sleep and fasting windows with our seasonal bedtime calculator and robust biorhythm calculator. Swap rigid schedules for nature’s timing: anchor bedtime to dusk and wake with rise sun. Our bedtime calculator uses your rise time and the optimal seasonal sleep duration to calculate your bedtime. Studies confirm syncing with natural cycles outperforms any sleep cycle tracker. Let the natural cycles guide you to entrain your biorhythm with optimal reminders for better sleep, meal, work & exercise times.

🍴 EAT & FAST IN SYNC WITH NATURE
Intermittent fasting and time-restricted eating work best when aligned to daylight. Front-load calories at sunrise and close your eating window by dusk to match your circadian rhythm. Research shows skipping breakfast or dining late disrupts this rhythm and harms metabolic health. With Circadian, set eating & fasting reminders that honor this timing for balanced blood sugar and deeper sleep.

🧬 THE SCIENCE OF CIRCADIAN RHYTHMS
Built on Nobel Prize–winning chronobiology, this circadian app explains how your internal clock and biorhythms regulate melatonin, cortisol, and vitamin D production. Getting the right circadian cues—light/darkness, food & exercise—at the right time is non-negotiable for a healthy body, mind, and heart. Use Circadian and its extensive learn & research section for tons of actionable insights on your sleep rhythm, artificial light, exercise timing, diurnal living and much more to transform your natural life.

🌅 YOUR NATURAL ALARM CLOCK
Wake gently with circadian rhythm alarm clock features: rise with the sun to greet the day. Getting natural light into your eyes for 5 minutes upon waking improves your sleep quality the next night by 20 %! Make rise sleep, rise sun, solar-noon check-ins, and sunset wind-downs part of your day. Let the surrounding natural life be your health clock tuning your biorhythms.

☘️ ENJOY TRUE RHYTHM & HEALTHY LIVING
As a top choice among health and wellness apps, Circadian focuses on pure nature-driven guidance—no complicated integrations. Enjoy better sleep and harmonious days shaped by your true rhythm.

🗝️ KEY ASPECTS
• Natural cycles: dawn, sunrise, UVA/UVB rise & set, solar noon, sunset, and dusk
• Bedtime calculator & biorhythm calculator: optimize your hours of sleep across the seasons
• Circadian rhythm alarm & health clock: custom alerts for medication, rise sleep, and much more
• Intermittent fasting in sync with nature: set your eating window to nature’s timing for better sleep, metabolism, and health
• Diurnal guidance: honor your true sleep rhythm—not a static sleep calendar or dissect every sleep cycle
• Core circadian library: 20+ deep-dive articles on melatonin, sunlight, menstrual cycles, grounding, and diurnal living science
• Embrace circadian sleep, vibrant energy, and a rhythm set by nature

Ready to unlock better sleep, balanced energy, and happier days?
Download Circadian: Your Natural Rhythm now — your ultimate circadian app and biorhythm calculator for natural cycles and optimal living.

Ratings and reviews

The app has great educational content and health articles. The notifications and alarms are also helpful. I travel full time so I have to update when I go to a new time zone manually. Otherwise, the notifications are off. Great app for helping get into a better flow with your circadian rhythms and education on the whys behind it.

Update - was emailed promptly about this issue, which is rare these days for apps. They corrected the issue within a few hours of me reaching out. I absolutely LOVE this app and have been using it for years. It really has helpede be more aware of my time spent inside, reminding me to get outside. A+ app and customer service Update erased my plan and settings, and is telling me I now have to pay a one time fee to use all the notifications that I previously used and paid for with my annual plan.

This is a great app if you are looking to align certain activities to daylight over the course of the year. They have also done a good job updating the app to resolve prior issues. When I had a problem with my subscription they responded quickly and rolled out an update to fix it. This is the best app I've found with adjustable sunrise/sunset alarm functionality.

What’s new

This update improves notifications, time updates, location handling, and more.

We're actively working to improve Circadian.
Here's to optimising your circadian rhythms and lifestyle one step at a time.

Mind your rhythm, mind your light ☀️
Team Circadian