Calendar

284 open source Calendar apps

Presentation Timer
APK
Simple timer for presentations. It rings bell at specified time. You can specify up to three bell timing. You can ring bell manually, too. When bell rings, the timer text color will be changed.
F-DroidGitHub
ProgressBars
APK
Countdown/up to/from a specified time * Percentage complete for a time interval * Notifications on timer completion * Swipe to delete timers * Drag to reorder timers * Show time remaining / elapsed in any combination of, Years, Months, Weeks, Days, Hours, Minutes, or Seconds
F-DroidGitHub
P
Protocol Berg Schedule
APK
The decentralized protocol and infrastructure conference. Protocol Berg v2 is a conference focusing on protocol research, decentralized infrastructure, and core-developer experience. The two-day event with multiple stages, opportunities for technical workshops, and protocol community gatherings brings together protocol researchers and other stakeholders from different decentralized protocols. Attendance is free of charge. The event will not host any sponsors or commercial talks. https://protocol.berlin Features * View program by day and rooms (side by side) * Custom grid layout for smartphones (try landscape mode 🙃) and tablets * Read detailed descriptions (speaker names, start time, room name, links, ...) of events * Search through all events * Add events to favorites list * Export favorites list * Setup alarms for individual events * Add events to your personal calendar * Share a website link to an event with others * Keep track of program changes * Automatic program updates (configurable in settings) * Vote and leave comments on talks and workshops 🔤 Supported languages (Event descriptions excluded) * Danish * Dutch * English * Finnish * French * German * Italian * Japanese * Lithuanian * Polish * Portuguese (Brazil) * Portuguese (Portugal) * Russian * Spanish * Swedish * Turkish 💡 Questions regarding the content can only be answered by the Protocol Berg content team. This app simply offers a way to consume and personalize the conference schedule. 💣 Bug reports are very welcome. It would be awesome if you can describe how to reproduce the particular error. The issue tracker can be found here: https://github.com/EventFahrplan/EventFahrplan/issues 🎨 Protocol Berg v2 logo: CC BY-NC-SA 4.0 Department of Decentralization
F-DroidGitHub
Proton Calendar
APK
Secure, encrypted calendar for your Android devices.
Direct
QRAlarm
APK
Say goodbye to oversleeping with QRAlarm! 🚀 QRAlarm - QR Code Alarm Clock is an effective and smart alarm clock that gets you out of bed by making you scan the QR or Barcode to turn off the alarm! This makes it perfect for both heavy sleepers and productive early risers! 🔝 Have you ever... - ⏰ ...found yourself caught in the “snooze loop” where you kept snoozing the alarm while never getting up? - 😴 ...turned off your alarm giving yourself those mythical “5 more minutes” just to fall back asleep again and oversleep? - 📝 ...wanted to start off the day earlier to get your tasks done but you simply couldn’t leave your bed in the morning? Then QRAlarm is perfect for you! 🫵 QRAlarm is not just another alarm clock app - the QR alarm mission functionality is there to help you always get up on time! Because a strong and innovative alarm clock does not only wake you up - it makes sure that you GET UP! 🙌 If you are seeking to: - Fight with oversleeping, - Break your snooze habits, - Improve your morning productivity, - Build your perfect morning routine, - Stay healthy and happy, Then you have found the perfect alarm clock application - this is your new life hack! 📈 QRAlarm is a simple and lightweight alarm clock! Don't worry about low memory in your phone - QRAlarm is only around 15 MB making it perfect fit for everyone, no matter the device! 📱 QRAlarm has a simple, clean and intuitive user interface that makes the experience easy and seamless! You will feel at ease using QRAlarm as it does not overwhelm the user with bloated functions. QRAlarm is uncluttered, clear and beautiful! ✨ Download the app now, set up and configure your alarms and let QRAlarm work its magic! 🪄
F-DroidGitHubIzzyOnDroid
Qadaa
APK
- Easy and simple interface. - Password for application - Sound and visual effects when spending a prayer or day - Motivated notifications when spending every day. - Dark mode of application. - Two modes of the first screen either photo or static color. - Direct pressure on the facade elements to spend the thing about it. - Determining the number of prayers a day. - Letter showing you the expiration date based on the number of prayers and the number of judges per day.
F-DroidGitHubIzzyOnDroid
QueueToDo
APK
Task management app. The queue instead of a task list to force execution order. Lightweight and simple.
F-Droid
Quick Timer
APK
Quick Timer Tile makes managing your time effortless and distraction-free.Add it to your Quick Settings, and you’re ready to go – no app icon or traditional interface. Everything happens through a timer dialog and notification.How to get started:Add the Timer to Quick Settings:Swipe down from the top of your screen to open Quick Settings.Tap the pencil icon or "Edit" to customize your tiles.Drag the "Timer" tile into the active area.Set up your timer:Tap the "Timer" tile to open the timer setup dialog.Grant notifications permission (if needed).Use the pickers to set the desired time and press "Start".Follow the Timer in Notifications:Once the timer starts, a notification shows the remaining time.Pause, resume, or cancel the timer directly from the notification with one tap.Why use Quick Timer?Quick access: start a timer in seconds straight from Quick Settings.No clutter: no app screen or icon – just a clean, efficient experience.Convenient notification: always know how much time is left at a glance.Perfect for cooking, workouts, or any activity where timing matters!
GitHubIzzyOnDroid
R
Radicale
Web
Lightweight CalDAV and CardDAV server for self-hosting calendars and contacts.
React
APK
Allows you to test your reaction time.
F-DroidGitHub
R
Record Time Droid
APK
RecordTimeDroid records time and shows elapsed time between previously recorded lines. It is useful to people who want to measure times for different tasks. It also is good for people who want to record date and time to store later.
F-Droid
Red Dot
APK
This parametric animation, under the current technology, is 49 years long, Starting 1970 January 1, it is not random, is synchronized over all devices and ideally never repeat itself. The Red Dot is just a symbol, a representation of something else. Take a look and find your our own meaning for it.
F-DroidGitHub
Remind Me!
APK
Have you found yourself in a situation where you wanted a *strong* reminder to something someday in the future?! A reminder wouldn't really do since it would just give you a notification, an e-mail, or a small _pling_ which can get lost in the abyss of notifications we receive every day. Have you thought, "Wish I could set an alarm for a future day/time"? Don't worry, RemindMe! Got you covered. PS: `SYSTEM_ALERT_WINDOW` permission is used because Android wouldn't let me start an activity from the background. Hence, I display a transparent system overlay for a very small duration (500 ms), then open the alarm activity as soon as the overlay gets drawn, and close the overlay later.
F-DroidGitHubIzzyOnDroid
Remindly
APK
Add reminders to the notification list.
F-DroidGitHub
Repeat Me
APK
Repeat Me is the cleanest, fastest, and most customize-able way to schedule notifications on your phone. With no ads or any questionable permissions, Repeat Me is the lightest and safest way to keep track of everything you need to do in your life.
F-DroidGitHub
Reservator
APK
Displays the availability status of meeting rooms along with the free/busy-time. Requires a Google-Account for schedules. Reservator is an open source meeting room display system for tablets. Mount your tablet next to your meeting rooms door, install Reservator and you're good to go! Reservator uses your Google calendar's resources for booking so you can use it, for example, for conference rooms, classrooms or for lending a video projector. While using Reservator, you can still book rooms normally through Google Calendar. You can also use the application for reserving other meeting rooms within your company. Features: * Integration: Reservator works with Google apps. * Booking: You can instantly book a meeting room with Reservator. You can also view the rooms calendar and book a meeting somewhere in the future. Simply pick the time and enter your name and it's booked. * Traffic lights: The display will be green if the room is available, yellow if a meeting is about to start soon and red if it's reserved. With this information you can quickly decide what conference room you want to use by just walking around.
F-DroidGitHub
RomanDigital
APK
The RomanDigital app provides a clock of unique style that can be used to repurpose an old device or to display time on a current model. For more personal use, the RomanDigital widget makes a distinctive addition to a device's Home screen. RomanDigital includes features expected in an ordinary digital clock, such as: * Choice of 12 or 24 hour format * Optional AM/PM indicator (uniquely integrated into the time display) * Option to keep display on when app is in the foreground * Display in either portrait or landscape RomanDigital also includes: * Independent configuration of app and widgets. * Selectable app and widget time display typeface (monospace, sans-serif, or serif). * Variable widget background opacity that can be set from 0% to 100% by tens. * Selectable widget time zone. * Selectable widget layouts to add a time zone label. * Selectable app time display color. For more detailed information including a FAQ list, please see the README.md file accompanying the RomanDigital source code. Source code for RomanDigital is available at: https://github.com/dfyockey/RomanDigital
F-DroidGitHubIzzyOnDroid
Roto
APK
Roto is an offline, privacy-first way to keep any rotating schedule on-device. Load a JSON rota, pin the widget, and check today or tomorrow at a glance—no accounts or trackers. - Works fully offline; optional one-time download from a user-provided HTTPS link - Handles repeating week cycles (Week 1/Week 2/Week 3...) anchored to real calendar Mondays - Supports per-date overrides without editing the base cycle - Flexible slots with labels, tags, and notes for menus, shifts, or duties - Homescreen widget for today/tomorrow - Ships with sample rotas and an AI-friendly prompt to generate your own JSON quickly All data stays local; dependencies are open source and F-Droid friendly.
F-DroidGitHub
Routine Tracker
APK
Routine Tracker is a planner that aims to simplify managing activities that you need to perform consistently. It combines features of a planner calendar app and a habit tracker allowing you to keep all your activities in one place.Features:Flexible schedules: The app supports daily, weekly, monthly, and alternate-day schedules. You're free to choose specific days or inform the app how many times you wish to complete the task within a period.Adaptive schedule that changes automatically based on your progress: When you fail to complete your routine, you’ll be suggested to sort out the backlog on the next non-due day. And vice versa, when you over-complete your routine, the next scheduled occurrence will be canceled. This behavior can be altered in the settings.Adequate streaks: Streaks do not only form out of multiple completions in a row. Non-due days are included in the streak as well. Your streak will remain unbroken as long as you complete the habit the planned number of times within a given period.Plan ahead: The routine calendar displays completions, streaks, and planning dates to help you visualize your progress and plan your future time effectively. View a clean and organized agenda for any date, eliminating visual clutter.Modern UI: Enjoy a visually appealing and modern interface, following the principles of the Material You design. The application supports both light and dark modes, landscape orientation, and dynamic color on Android versions 12 and later.Completely free app with no limitations: Track as many habits as you wish. Routine Tracker is entirely free and contains no ads or in-app purchases.Works offline and respects your privacy: Routine Tracker operates independently without needing an internet connection or online account registration. Your confidential data always remains on your device. Neither the developers nor any third parties can access your information.More to come, so stay tuned…
GitHubIzzyOnDroid
R
RxDroid
APK
A simple medication reminder. Also keeps track of your pill count and required refills. Help with translating RxDroid to your language at crowdin.com!
F-DroidGitHub
Salat Times
APK
The app can use GPS to find your location, although you can enter geographic coordinates. It calculates prayer times, gives notifications and has a Qibla for showing the direction of Mecca.
F-Droid
Screen Time
APK
Displays your screen time in a permanent notification. By making screen time more prominent, you can get a better sense of how much of the day you spend on your phone. Without judgement. Just so you know. This is open source: https://github.com/markusfisch/ScreenTime
F-DroidGitHubIzzyOnDroid
Scrum Chatter
APK
Time members while they speak at meetings. See who chatters the most in meetings. View average and total speaking time of members for all recorded meetings. Share the stats for one meeting or for all meetings. Export to Excel so you can add your own lovely charts and graphs as you see fit. You can export and import the database. Note: this app does NOT use the microphone to automatically detect when a person is speaking. You must press on a "play" button when a team member speaks.
F-DroidGitHub
Self Attendance Tracker
APK
Using Self Attendance Tracker, students can track their class attendance on their own. They can 1. See the classes they have to attend today 2. List of course for which attendance is being tracked and see presents, absents and cancelled classes per course 3. Create schedule for the week so that these schedule classes are repeated weekly 4. Create extra classes that are additional to the weekly schedule classes 5. See marked attendance record for a specific course
F-DroidGitHub