Clean an .ics export where the same event was saved several times, keeping the latest
Processed in your browser. Nothing is uploaded. Checked against sources on 17 Oct 2026.Importing the same calendar twice, or syncing two accounts, leaves events doubled. Every calendar event carries a unique ID, and an updated invitation carries a higher sequence number. Drop the .ics files here and each event is kept once: the copy with the highest sequence number, or the most recently stamped one. Delete the old calendar in your app and import the cleaned file.
Drop your files or click to choose them.
Adjust the options and check the preview.
Download the result. Nothing was uploaded.
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.
| 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 |
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.
The rest of the article, and all 6 questions about Merge ICS Files, are on the Merge ICS Files page.
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.
Rates and rules change; check the source before you rely on a figure.
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Same job, other tools: Remove Duplicate Contacts from VCF – Find contacts saved twice in a VCF backup and keep one of each, numbers combined · Markdown to Plain Text – Strip every Markdown mark and keep the words.
On the related tools: Combine CSV Files – Stack monthly or per-store CSV exports into one file, with a column naming the source.