Quick answer
Apple Calendar refreshes subscribed feeds about once an hour. Google Calendar refreshes every 12 to 24 hours and has no faster setting. Outlook and Microsoft 365 sit in the 1 to 4 hour range. For changes that have to reach subscribers in the next 30 minutes, send a text or email alongside the edit.
At a glance
| Platform | Refresh interval | Source |
|---|---|---|
| Apple Calendar (iOS, iPadOS, macOS) | About once per hour by default; user-configurable from 5 minutes to never | Apple Support |
| Google Calendar | 12 to 24 hours; no faster setting for user or publisher | Google Workspace |
| Outlook / Microsoft 365 | 1 to 4 hours typical; up to 24 hours worst case | Microsoft Support |
Subscribed calendars do not get pushed. The subscriber's calendar app pulls. The poll interval between pulls is set by the app, not the publisher.
Here is what each major app actually does.
Apple Calendar (iOS, iPadOS, macOS)
Apple Calendar checks subscribed feeds about once an hour by default. The user can change it to 5 minutes, 15 minutes, hourly, daily, weekly, or never. Most users leave it on hourly. (Apple's own subscribe-in-iCloud doc walks through the URL flow per device.)
This is the fastest of the major calendar apps. For a typical weekly schedule, Apple subscribers see every edit within 60 minutes.
There is no setting for the publisher to make the refresh faster. The cadence is per-subscriber, per-device.
Google Calendar
Google Calendar checks subscribed feeds every 12 to 24 hours. There is no user setting to make it faster. There is no publisher setting either. (Google's own subscribe-to-a-calendar guide covers the From-URL flow without exposing a refresh control.)
This is the cadence that surprises new publishers. An event added on Monday afternoon may not appear in Google subscribers' calendars until Tuesday morning. For most schedules this is fine because the next event is still days away. For last-minute changes it is not fine.
Google does this to limit how often its servers poll third-party feeds. There is no way around the poll cadence.
Outlook and Microsoft 365
Outlook on the web and Microsoft 365 sit in the middle. Refresh happens every 1 to 4 hours, depending on the account type and load. (Microsoft's subscribe-or-import guide notes updates can take up to 24 hours in the worst case.)
Outlook desktop is similar but can be slower if the app is closed.
What this means for publishers
Publishers should plan around the slowest subscriber, which is Google at 12 to 24 hours. Anything added days ahead reaches every app in time. Anything inside 24 hours needs a backup channel.
For a normal weekly schedule, the polling cadence is invisible. You add events days or weeks in advance. Everyone sees them well before they happen.
For edits inside the next 24 hours, the cadence matters. A practice cancellation announced 30 minutes before start time will reach Apple subscribers in time but will not reach Google subscribers in time. For those cases, send a one-off email or text too. See how to share a calendar with a group for when to use the calendar vs the emergency channel.
Calfeed will eventually add an out-of-band notification path so a single edit can fire both the feed update and an email blast to subscribers who opted in. Until then, treat the calendar as the source of truth and the text message as the emergency channel.
What subscribers can do
Subscribers on Google cannot speed up their own polling. The setting does not exist.
Subscribers on Apple can drop their refresh interval to 5 or 15 minutes for a specific calendar. Right-click the calendar in the sidebar, pick "Get Info", change "Auto-refresh".
For most groups, hourly is fine. For one urgent calendar, ask Apple subscribers to set it to 15 minutes.
Test a subscription link before you share it.