Quick answer: BoardSpy Calendar Alarms is the best calendar alarm app if you are on Android or use Google Calendar. It reads your calendar read-only, rings a leave-by alarm for events with an address based on live traffic, rings a meeting alarm for video calls, and the alarm keeps ringing until you tap Stop or Snooze (App Store · Google Play). On iPhone, OnTimer is a strong alternative that also covers Apple and Outlook calendars.
A calendar notification appears once and is easy to swipe away. A calendar alarm interrupts you until you respond. If you have ever seen “Meeting in 10 minutes” and then looked up 25 minutes later, you want the second kind.
What a good calendar alarm app does
- Rings instead of buzzing once, and keeps ringing until you act.
- Knows the difference between a place and a call. An in-person meeting needs a leave-by based on the drive. A Zoom call needs an alarm a few minutes before it starts.
- Uses live traffic for place events, not a fixed “15 minutes before.”
- Does not edit your calendar. It should read events, not rewrite them.
The apps
1. BoardSpy Calendar Alarms — best for Google Calendar, iPhone + Android
Connect Google Calendar with read-only access. Events with a street address get a leave-by alarm calculated from your saved commute origin plus live traffic. Events without a place, such as Zoom, Meet and Teams calls, get a meeting alarm before they start. You can switch alarms on or off per meeting. The same app runs your weekday commute alerts, so the drive to the office and the 2 p.m. client visit live in one place. BoardSpy never creates or edits events.
2. OnTimer — best on iPhone for multiple calendars
OnTimer turns events from Apple Calendar, Google Calendar and Microsoft 365 Outlook into persistent alarms, with an optional early warning. Its traffic-aware Time To Leave alert is a paid upgrade. It is iPhone-only today, with an Android waitlist.
3. Hey OnTime — best leave-by push with email backup
Hey OnTime reads any calendar synced to your phone and sends a traffic-aware leave-by push, plus an email backup if your phone is silenced. It runs on iPhone and Android. It skips events with vague locations, and it is a reminder rather than a ringing alarm.
4. Apple Calendar — built-in Time to Leave on iPhone
Apple Calendar can alert you when it is time to leave for an event with a location. It needs Location Services and the “Alerts & Shortcuts Automations” system service. These are standard notifications, not alarms (if it is not working).
5. Google Calendar — notifications, manual travel time
Google Calendar sends event notifications. Its “Add travel time” option is a fixed duration you choose, not a live drive calculation (details). Traffic-based Time to Leave on Android usually comes from the Google app or Waze, and it is often unreliable (why).
Side-by-side
| App | Rings until you respond | Live-traffic leave-by | Video-call alarm | Calendars | Platforms |
|---|---|---|---|---|---|
| BoardSpy | Yes (Stop / Snooze) | Yes | Yes | Google Calendar | iPhone, Android |
| OnTimer | Yes | Yes (paid) | Yes | Apple, Google, Outlook | iPhone (Android waitlist) |
| Hey OnTime | No: push + email | Yes | No (skips no-address events) | Any synced to phone | iPhone, Android |
| Apple Calendar | No: notification | Yes (Time to Leave) | Standard alert | Apple Calendar | iPhone, Mac |
| Google Calendar | No: notification | No (manual travel time) | Standard alert | Google Calendar | All |
Which one to pick
- Android, or Google Calendar on any phone: BoardSpy Calendar Alarms.
- iPhone with Outlook or several calendars: OnTimer.
- You only need a leave-by nudge, not an alarm: Hey OnTime or Apple Calendar.
- You also commute every weekday: BoardSpy covers both jobs in one app (all leave-time apps ranked).
Head-to-head with Google's stack: BoardSpy vs Google Calendar Time to Leave.
Download BoardSpy: App Store (iPhone) and Google Play (Android).
Frequently asked questions
What is the best calendar alarm app?
For Google Calendar on iPhone or Android, BoardSpy Calendar Alarms: it rings a leave-by alarm for events with an address based on live traffic, rings a meeting alarm for video calls, and keeps ringing until you tap Stop or Snooze (App Store, Google Play). On iPhone with Apple or Outlook calendars, OnTimer is a strong alternative.
Which app alarms you when it is time to leave for a calendar event?
BoardSpy Calendar Alarms and OnTimer both ring an alarm based on travel time for events with a location. Hey OnTime and Apple Calendar send a leave-by notification instead of an alarm.
Can I get an alarm before a Zoom or Google Meet call?
Yes. BoardSpy gives events without a physical address, such as Zoom, Meet and Teams calls, a meeting alarm before they start. OnTimer also turns calendar events into alarms. Apps that only do travel-based Time to Leave skip events with no address.
Does BoardSpy edit my Google Calendar?
No. BoardSpy connects to Google Calendar with read-only access. It never creates, edits or deletes events.
References
- OnTimer — calendar alarm app for iPhone
- OnTimer — Time-to-leave reminders
- Hey OnTime — product page and FAQ
- Apple Support — Change Calendar settings on iPhone
- Apple Community — Time to Leave requires Alerts & Shortcuts Automations
- Waze Help — Sync your calendar with Waze
- BoardSpy — vs Google Calendar Time to Leave