iCal vs. .ics vs. CalDAV: What's the Difference?

The terms iCal, .ics, CalDAV, and webcal get used interchangeably, but they mean very different things. Getting iCal vs .ics vs CalDAV straight makes calendar sharing and syncing far less confusing. This guide defines each term in plain English and shows when each one applies.

Quick comparison

iCal: the app (mostly retired name)

"iCal" was the name of Apple's calendar app on the Mac for years. Apple renamed it to simply Calendar over a decade ago, but the old name stuck in conversation. So when someone says "open it in iCal," they almost always mean the Calendar app on a Mac or iPhone.

Confusingly, "iCal" is also sometimes used loosely to mean the file format below. That overlap is exactly why people get tangled up.

.ics: the file and the standard

.ics is the file extension for the iCalendar format, an open standard understood by Apple Calendar, Google Calendar, Outlook, and nearly everything else. It's plain text describing events (title, time, location, repeat rules). For a deep dive, see what is an .ics file.

Key point: .ics is data, not a connection. A file is a snapshot. It only becomes "live" when it lives at a URL you subscribe to.

webcal://: a subscribe link

webcal:// is not a separate format — it's a URL scheme that points to an .ics feed and signals "subscribe to this." When you click a webcal:// link, your device offers to add it as a subscribed calendar.

• Swapping webcal:// for https:// usually returns the same .ics file.
• Use webcal:// to subscribe; use https:// to download or inspect.

See how to subscribe to a calendar by URL.

CalDAV: the sync protocol

CalDAV is the heavyweight of the group. It's a two-way protocol that keeps a calendar app and a calendar server continuously in sync. iCloud, Google, and Fastmail all use CalDAV (or similar protocols) behind the scenes.

If you want to view a feed, you subscribe to an .ics/webcal link. If you want to add and edit events that sync everywhere, you connect a CalDAV (or Exchange/Google) account. See sync iCloud with Google or Outlook.

Putting it together with a real example

Say a sports team publishes its schedule:

1. They host an .ics feed (the format/standard) at a web address.
2. They give you a webcal:// link (the subscribe prefix) to it.
3. You open it in Calendar (formerly "iCal," the app) and it becomes a read-only subscription — refreshed on a schedule, not CalDAV.
4. Your own iCloud or Google calendar — where you create your own events — runs over CalDAV, syncing both ways.

Cheat sheet

• Someone says "iCal" → they mean the app (or, loosely, an .ics file).
• A link ends in .ics → it's a feed/file you import or subscribe to.
• A link starts with webcal:// → tap to subscribe.
• You signed into an account → that's CalDAV/Exchange/Google two-way sync.

Related reading

• What is an .ics file?
• Subscribe to a calendar by URL

If you use Google and Outlook, nocal unifies those calendars into one timeline — see how.