How Often Does a Subscribed Outlook Calendar Update in Google — and How to Force It

You moved a meeting in Outlook this morning. It's afternoon, and Google Calendar still shows the old slot. Nothing is broken — Google refreshes subscribed calendars on a slow clock of its own, and there's no button to hurry it along.

How long the wait actually is

The interval depends entirely on which app holds the subscription, and the spread is wide:

• Google Calendar: roughly every 8 to 24 hours, sometimes longer. There's no published guarantee; in practice people report anything from a few hours to a couple of days. One widely-read Google support thread is titled, word for word, "Google Calendar does not sync URL-linked calendars within 12 hours as stated." Google throttles external fetches to save load, and it's the slowest of the mainstream clients.
• Apple Calendar (Mac/iPhone): configurable. You can set the auto-refresh down to about 5 minutes, though the default behaves more like every 1–3 hours.
• Outlook.com on the web: about every 3 hours.
• Outlook desktop: on launch, then roughly every 1–3 hours.

So "it hasn't updated" usually means "it isn't due yet." The genuinely frustrating one is Google: no interval setting, no honest manual refresh.

The refresh button is a trap

Google Calendar does have a circular refresh icon. It does nothing for subscribed feeds — it only reloads your own Google calendars in the browser. The external ICS feed gets fetched on Google's schedule no matter how many times you click. This is the single most common piece of wasted effort in every forum thread on the subject.

What actually forces an update

When you truly can't wait, these are the moves people trade:

• Delete and re-add the subscription. Remove the calendar, then subscribe to the same URL again — Google fetches fresh data immediately. The most reliable manual trigger, and the most tedious.
• Change the URL so Google thinks it's new. Append an anchor like #1 to the end of the link (or switch https:// to webcal://) and subscribe to that. Google treats the slightly different URL as a brand-new calendar and pulls it on the spot.
• Run an Apps Script on a timer. The open-source GAS-ICS-Sync project re-fetches a feed every few minutes and writes it into a real Google calendar. It works, but it's a developer's solution — script editor, triggers, the lot.

None of these change Google's underlying interval. They force a one-off fetch, or sidestep the subscription mechanism entirely.

If you publish from the Outlook desktop app

There's a publisher-side trap worth knowing. In classic Outlook desktop, go to File → Account Settings → Account Settings → Published Calendars, open your calendar, and look for the "Update Limit" checkbox. Left ticked, it caps how often Outlook re-uploads the feed to the provider's limit — and plenty of people find the published copy then never updates at all. Unticking it lets the feed refresh on a normal schedule. If your source feed is stale, nothing you do on the Google side will help.

Where CalConverter helps — and where it can't

Be clear-eyed: nobody can make Google poll an external feed faster from the feed's side, and CalConverter doesn't pretend to. What it removes are the other two reasons a calendar looks frozen — the ones you can actually fix:

• A feed Google chokes on. If the underlying ICS carries Windows time-zone names or malformed blocks, Google can quietly stop refreshing, or never show the new events at all. CalConverter serves a clean, standards-compliant feed and keeps a current copy ready, so each time Google fetches, it gets valid data.
• A publish link that died silently. Re-publishing in Outlook can mint a new URL and kill the old one. The feed looks "stuck" but is actually disconnected. Convert the fresh link once and the subscription is live again.

Near-real-time refresh as an opt-in is on our roadmap — follow the News page. Until then, if your calendar is wrong rather than just late, that's the part to fix first:

• Times off by an hour or more → Google Calendar shows wrong times for Outlook events.
• Calendar imported once, then froze or went empty → Outlook calendar not syncing with Google Calendar.