What is an .ics file and where can I use it?

An .ics (iCalendar) file is the universal calendar interchange format defined by RFC 5545. Almost every calendar app reads it: Google Calendar, Apple Calendar, Microsoft Outlook, Thunderbird, Fastmail and more. Double-click or import the file and the event is added with its title, time, location, recurrence and reminders intact.

Does the tool create recurring events?

Yes. You can repeat an event daily, weekly (on specific weekdays such as Mon, Wed, Fri), monthly or yearly, set an interval like every 2 weeks, and either stop after a number of occurrences or on an end date. The tool writes a standard RRULE so the recurrence is honoured by any calendar app.

How do the Add to Google and Add to Outlook buttons work?

They build a pre-filled calendar link for Google Calendar and Outlook.com that opens the new-event screen with your title, time, location, description and recurrence already populated. You just review and save. The .ics download works for every other app, including Apple Calendar and desktop Outlook.

Are my event details sent anywhere?

No. The entire file is generated in your browser using JavaScript. Nothing is uploaded to a server, and your most recent event is saved only in your own browser via local storage so you can return and edit it later.

How are time zones handled?

You can attach an IANA time zone such as Europe/London or America/New_York, which writes a TZID so the event stays at the right local time wherever it is opened. Leave it on Floating to keep the same wall-clock time in every zone, or choose UTC. All-day events are date-only and ignore time zones by design.

Can I put more than one event in a single file?

Yes. Add as many events as you like and Download .ics bundles them all into one calendar file, which is handy for sharing a schedule, an itinerary or a series of meetings. You can also download just the event you are currently editing.

Why is the end date one day later for all-day events?

The iCalendar spec treats the all-day end date as exclusive, so a one-day event on the 10th is stored with an end of the 11th. The builder handles this automatically — you pick the last day the event covers and it writes the correct exclusive end so calendars show the right span.

ICS Calendar Event Builder

The ICS Calendar Event Builder turns a simple form into a valid .ics (iCalendar) file you can import into any calendar app — and gives you one-click Add to Google and Add to Outlook links at the same time. It is for anyone who needs to send a calendar invite, publish an event, share an itinerary, or drop a recurring meeting onto someone else’s calendar without wiring up a whole booking system. You fill in the title, location, dates, recurrence and a reminder, and the tool produces a clean, standards-compliant file that Google Calendar, Apple Calendar, Outlook, Thunderbird and Fastmail all understand.

Most “add to calendar” widgets only generate a single web link for one provider. This builder does more: it writes the actual RFC 5545 file with correct line folding, character escaping, time-zone handling and recurrence rules, so the event looks right no matter which app opens it. You can stack multiple events into one file, attach a VALARM reminder, mark an event tentative or cancelled, and add an organizer — all client-side, with your last draft auto-saved in your browser so nothing is lost between visits.

How it works

Each event you create becomes a VEVENT block inside a single VCALENDAR wrapper. The tool fills in the mandatory fields — a unique UID, a DTSTAMP, and DTSTART / DTEND — then adds the optional ones you supply: SUMMARY, LOCATION, DESCRIPTION, URL, STATUS and ORGANIZER. Free-text values are escaped so that commas, semicolons and newlines never break the format, and long lines are folded to 75 characters per the spec.

Timed events can carry an IANA time zone, written as a TZID parameter so the event stays anchored to the correct local time. Pick Floating to keep the same clock time everywhere, or UTC for an absolute instant. All-day events are stored as date-only values, and because iCalendar treats the all-day end as exclusive, the builder quietly adds a day so your span is correct. Recurrence is expressed as a standard RRULE: frequency, interval, selected weekdays for weekly events, and either a COUNT or an UNTIL end. A reminder becomes a VALARM with a negative TRIGGER offset. The same data drives the Google and Outlook deep-links, so the web buttons match the downloaded file.

Example

Suppose you want a stand-up that runs every weekday at 09:30 for 20 minutes, with a 10-minute reminder. Set the start to 09:30 and the end to 09:50, choose Weekly, tick Mon, Tue, Wed, Thu, Fri, and pick 10 minutes before as the reminder. The recurrence summary reads “Every week on Mon, Tue, Wed, Thu, Fri”, and the generated rule is RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR.

Field	Value
Title	Daily stand-up
Start	09:30
End	09:50
Repeats	Weekly, Mon–Fri
Reminder	10 minutes before
Export	`daily-stand-up.ics`

Click Download .ics and import the file once; every weekday occurrence and its reminder appear automatically. Or click Add to Google to open the same event pre-filled in Google Calendar. Everything is computed in your browser — no event details are uploaded or stored on a server.