Combine .ics calendar files into one, each event once and its newest version kept
Processed in your browser. Nothing is uploaded. Checked against sources on 17 Oct 2026.Merge ICS Files combines up to 50 iCalendar files into one .ics in your browser, writing each event once. Copies are matched by their unique ID, and the newest version wins. Reminders, attendees, repeat rules and time zones are copied exactly, and nothing is uploaded.
Press Select calendar files, or drop two or more .ics files on the page; they are read on your device.
Read how many events were copies of each other; the newest version of each is kept.
Name the calendar, and tick Leave out events that are over if you only need what is coming.
Press Download and import the single .ics in Google Calendar, Outlook or Apple Calendar.
Calendar apps export one .ics file per calendar. Moving from Outlook to Google, keeping an archive, or sharing a combined family and school calendar means importing several files, and the same meeting held in two calendars then shows twice.
How copies are recognised. iCalendar gives every event an identity, and this page uses it the way the standard intends:
| Field | What it decides |
|---|---|
| UID | Which event this is, the same in every copy |
| RECURRENCE-ID | Which single occurrence of a repeating event was changed |
| SEQUENCE | Which version is newer; the organiser raises it on each change |
| DTSTAMP, LAST-MODIFIED | Breaks a tie between equal sequence numbers |
So an invitation that was moved after you exported your calendar replaces the older copy, and a changed occurrence of a weekly meeting is kept beside its series rather than merged into it. Items written without a UID are matched on their title and start time.
What is copied. Events, to-dos and journal entries are copied line for line, with their reminders, attendees, organisers, repeat rules and custom fields. Time-zone definitions are kept once per zone. The file gets a new header with the calendar name you choose, and no METHOD line, so calendar apps import it as a calendar rather than treating it as an invitation to answer.
Only what is coming. Tick Leave out events that are over to drop one-off events that have ended; repeating events always stay, since their next occurrence may still be ahead.
Tested against a brute-force pick of the winning copy on 200 random sets of calendars, read back with a separate line scanner. Nothing is uploaded.
Drop both .ics files on Merge ICS Files. Their events, to-dos and time zones are combined, any event found in both is written once, and the page says how many items the merged calendar holds. Press Download and import the single .ics wherever you need it.
The copy with the highest SEQUENCE number, which the organiser raises every time the event changes. When two copies share a number, the more recently stamped one wins; when they are identical, the first is kept. The kept copy stays where the first one was.
Yes. Each event is copied line for line, so reminders, attendees, the repeat rule, exceptions and custom fields are unchanged. A single changed occurrence of a weekly meeting keeps its own RECURRENCE-ID and stays beside its series.
Open Google Calendar on a computer, go to Settings, then Import and export, choose the merged .ics and pick the calendar to add it to. Outlook uses File, Open and Export, Import; Apple Calendar uses File, Import.
Yes. Tick Leave out events that are over and one-off events that ended before today are dropped from the merged file. Repeating events are always kept, because their next occurrence may still be ahead even when the first one has passed.
No. The files are read and merged by your own browser, and the new .ics is created on your device. Meeting titles, attendees and notes never reach a server, and closing the tab removes everything.
Rates and rules change; check the source before you rely on a figure.
Still stuck? Ask about Merge ICS Files and anybody who knows can answer. No account needed.
Same job, other tools: Combine VCF Files – Join several contact exports into a single VCF for a one-step import · Combine CSV Files – Stack monthly or per-store CSV exports into one file, with a column naming the source.