90night is a free app that can be used to calculate your sleep cycles and the times you can wake up.

It is inspired by the popular website sleepyti.me and works similarly.

It can be used on Android devices.

The app is free and works without any ads.

How can I use the app?

To use the app, first, select the format that you want to use (hour or day).

Second, choose the length of your cycle.

Third, choose the day of the week.

To finish, press the Calculate button.

To find out when you can wake up, press the "Wake up" button.