Plan your day, energy and sleep in harmony with the natural rhythm of sunlight.

SunBioClock transforms local sunrise and sunset times into a clear visual clock that helps you understand how your day and night are progressing.

Instead of following the same schedule throughout the year, SunBioClock recalculates your suggested sleep and wake times every day according to the changing time of sunrise.

See your day at a glance

The visual solar chronometer gives you a simple overview of:

• how much daylight or nighttime has already passed,

• how much time remains until sunrise or sunset,

• the current solar and circadian phase,

• the recommended time to wind down, sleep and wake up.

Plan your energy around natural light

Use SunBioClock to organize work, focus, rest and sleep in a way that follows the changing rhythm of the seasons.

The app automatically adapts to your location and to the real length of each day and night.

Your calendar on a 24-hour solar clock

Connect calendars synchronized with your Android device, including Google Calendar, and display upcoming events directly on the 24-hour SunBioClock dial.

See your schedule together with sunrise, sunset, sleep time and other important solar milestones.

Annual daylight and nighttime chart

Explore an interactive yearly chart showing how the duration of daylight and night changes throughout the year.

Compare seasons, select individual dates and see the corresponding sunrise and sunset times.

Free flexible home screen widget

Follow the remaining time until the end of the current day or night directly from your Android home screen.

Calming bedtime reminders

Receive a gentle full-screen bedtime reminder even when you are using another app.

The reminder helps you notice that your planned sleep time has arrived and encourages you to slow down and prepare for rest.

Explore sunrise and sunset anywhere

Use the interactive 3D globe to select almost any location in the world and calculate its local sunrise, sunset and solar rhythm.

Compare your home location with another city, travel destination or place of interest.

Key features

• Sunrise and sunset countdown

• Dynamic solar and circadian clock

• Daily sleep and wake-time calculation

• Day, transition and night modes

• 24-hour clock with calendar events

• Annual daylight and nighttime chart

• Interactive 3D location selection

• Flexible Android home screen widget

• Bedtime notifications and full-screen reminders

• Local solar calculations without an external solar API

Free app

The core SunBioClock experience and the home screen widget are free to use.

Privacy-friendly by design

Solar calculations are performed locally on your device.