Sleep Cycle Calculator helps you figure out when to go to sleep, and when to wake up, in order to feel rested, energized and refreshed and avoid the morning groggy feeling.


This is a free sleep app that can set an alarm for you to wake up in-between sleep cycles in order to start the day relaxed and with a clear mind.

Every time you go to sleep, you experience a series of sleep cycles that last on average 90 minutes, and waking up during one of the sleep cycles makes you feel groggy and exhausted even with plenty of hours of sleep - sleep cycle calculator tries to determine the best wake up times, or go to bed time in order to workaround this situation.

Perfect at figuring out sleep cycles and recommended for people who have trouble sleeping and don't have a fixed sleeping schedule.

There are four sleep calculation scenarios to choose from:
Scenario 1: you want to know when to go to sleep in order to wake up at a specified time. Sets a go to bed alarm.
Scenario 2: you want to know when to wake up if you go to bed at a specific time. Sets a wake up alarm.
Scenario 3: you want to know the best times to wake up if you go to sleep right now.
Scenario 4: you plan to take a power nap and you want to know when you should wake up.

What this app does
• This Sleep Calculator app is the Android companion of the website https://sleep-calculator.com/
• Calculates when you should wake up and when you should go to sleep in order to wake up in-between sleep cycles.
• Calculates when you should wake up if you were to go to sleep now or take a power-nap.
• Calculates a list of possible "go to bed" or "wake up" times depending on your needs.
• The app is able to add alarms to the default Android Alarm app by selecting a time entry available in the sleep cycles list.
• Sleep Calculator provides a settings option to take into account the time it takes for you to fall asleep (default: 14 minutes).
• Sleep Calculator provides a settings option to take into account the length of a sleep cycle (default: 90 minutes).
• The clock hour format used by sleep calculator is the devices current system setting (24 hours format or the AM/PM format).
• Option to choose from 7 different themes / skins.
• Option to choose from the available application translations in case you don't want to app in your native locale or have a language preference..

What this app does not
It's not an alarm clock app replacement, it only allows you to add an alarm to your Android stock alarm clock app.

Translators:help translate Sleep Calculator in your language so others can enjoy it too! Join the translation project here: https://sleepcalculator.oneskyapp.com/collaboration

Keep in touch
Facebook: https://www.facebook.com/sleepcyclecalculatorapp/
Uservoice: http://sleepcalculator.uservoice.com/

Android version support: 4.1+

Intelligent Caller ID functionality added. Caller ID now helps you identify callers - even the ones not in your contact list. This feature is optional and you can adjust or disable Caller ID at any time in the settings menu.

// Option A //

To download Sleep Calculator mod from HappyMod.com.
You need enable the option "Unknown Sources".
1. Click on the above link to download Sleep Calculator mod APK.
2. Save the file in your device Downloads folder.
3. Now tap on Install and wait for the installation to finish.
4. Once it is done, open the game and start playing it right away.

// Option B //

To download Sleep Calculator from HappyMod APP, you can follow this:
1. Open your browser and download the HappyMod APK file from HappyMod.com - the only official website of HappyMod.
2. Open Android Settings and go into Privacy or Security.
3. Tap the option to Allow Unknown Sources and enable it.
4. Go to your Android downloads and tap the APK file.
5. Follow the directions on the screen to install it.
6. Search Sleep Calculator in HappyMod App.