CSV to ICS Converter — Free, Private, In Your Browser

How the converter works

The CSV format this converter understands

The first row of your file should be headers; every row after it is one event. Column order doesn't matter, header capitalization doesn't matter, and only Subject and Start Date are required. This is the same layout Google Calendar and Outlook use for their own CSV exports, so those files convert with zero editing.

Not sure your file matches? Download the sample.csv template — it covers timed events, all-day events, a multi-day event, commas inside quoted cells and a row with no end time, so you can see how each case converts.

Date and time formats that just work

Spreadsheets are messy, so the parser accepts the formats people actually type rather than demanding one canonical form:

• Dates: 2026-07-24 · 07/24/2026 · 7/4/26 · 24/07/2026 (day-first when the day is >12) · 24.07.2026 · July 24, 2026 · 24 Jul 2026
• ISO date-times: values like 2026-09-05T14:00:00Z are accepted and converted into the timezone you pick
• Times: 9:00 AM · 09:00 · 14:30:00 · 9am · 9.30pm · noon · midnight
• All-day flags: True, Yes, Y, 1 or X all count as "yes"

One honest caveat: a date like 3/4/2026 is genuinely ambiguous. The converter defaults to month-first (March 4) because that is how Google Calendar and Outlook write their CSV exports. If your file is day-first throughout, the preview cards will make the mix-up obvious before anything reaches your calendar — that's exactly what the preview step is for.

What the validation report actually checks

Most CSV-to-calendar converters fail quietly: a bad row vanishes, an inverted end time becomes a negative-duration event, a missing title imports as a blank block. Google Calendar's own CSV import is the same — Imported 0 out of 0 events. Unable to process your iCal/CSV file with no row numbers. The report above the download button is the opposite of that.

• Unreadable start date — the row is skipped and listed with its CSV row number, so you can fix the cell instead of hunting.
• End before start — timed rows get the end reset to start + 1 hour; all-day rows with a backwards end date become a single-day event. Either way you see the warning before the file lands in a calendar.
• Missing title — kept, labelled (untitled event), counted. Blank-title rows are a common Excel export artefact, not a reason to drop the date.
• Ambiguous 03/04-style dates — read month-first because that is how Google and Outlook write CSV. The warning fires when both numbers are ≤ 12, so a UK-style file is obvious in the preview.
• Timezone tokens inside cells — GMT, UTC, −05:00 and similar. The converter still applies one zone (the dropdown) to the whole file. If those tokens meant a second zone, strip them or split the file first.

A clean file shows a green line: all N events parsed, no warnings. That is the only green light that matters — the download button still works with warnings, because some repairs (the +1 hour default) are what you wanted.

Timezones, DST and why VTIMEZONE matters

The single most common way CSV-to-calendar conversions go wrong is time shifting: you convert a 9:00 AM meeting and it lands at 1:00 PM. That happens when a converter writes naive UTC timestamps without recording which timezone the times were meant in.

This converter does it properly. You choose an IANA timezone (it defaults to the one your browser reports), and every timed event is written as a local time with a TZID reference — for example DTSTART;TZID=America/New_York:20260728T090000. The file also embeds a matching VTIMEZONEblock that encodes the zone's daylight-saving transitions, computed from the real timezone database built into your browser. The practical result: a 9:00 AM standup stays 9:00 AM whether the date falls in EST or EDT, and attendees in other timezones see it correctly shifted.

Prefer absolute times? Select UTC and the converter writes Z-suffixed timestamps (20260728T130000Z) with no VTIMEZONE — useful for server-side feeds and log-style calendars.

All-day, multi-day and recurring events

All-day events are triggered two ways: an All Day Event column set to True, or a row with a date but no start time (a toggle in the options controls that second behavior). They are written as VALUE=DATE entries, which calendars render as banner events rather than midnight-to-midnight blocks.

Multi-day events just need an End Date. The ICS spec has a famous trap here — DTEND is exclusive, so a naive converter makes your Aug 10–12 conference end on the 11th. This converter treats the end date in your CSV as inclusive (the way humans mean it) and adds the extra day in the file for you.

Recurring eventsare the one thing CSV genuinely cannot express — there is no standard recurrence column, and Google's own CSV import doesn't support one either. For a handful of occurrences, duplicate the row per date. For true repeating rules, generate the ICS here and add an RRULE line to the event — our guide to creating ICS files by hand shows the syntax with copy-paste examples.

Your file never leaves your device

Calendar exports are personal: names, meeting titles, addresses, sometimes medical or legal appointments. Most online converters upload your file to a server to process it — and you have no idea how long it sits there.

This tool takes the other approach: the parsing (PapaParse) and ICS generation both run as JavaScript in your browser tab. Nothing is uploaded, nothing is stored, and the conversion even works offline once the page has loaded. You can verify this in your browser's network tab — after the page loads, converting a file produces zero network requests. The same is true of our ICS to CSV converter and ICS viewer.

Importing the ICS into your calendar

The downloaded .ics file is plain RFC 5545 iCalendar — the universal interchange format — so it imports anywhere. Each app hides its import button in a different place, though, so we keep an up-to-date walkthrough per app:

• CSV to Google Calendar — Google can also import CSV directly; we cover when to use which route.
• CSV to Outlook calendar — classic Outlook's import wizard vs. new Outlook and Outlook.com, which only take ICS.
• CSV to Apple Calendar — Apple Calendar has no CSV import at all, so converting to ICS is the only route; steps for Mac and iPhone.

CSV to ICS — frequently asked questions