Free tool
Download an event as an ICS file.
The file opens in Google Calendar, Outlook, and Apple Calendar.
Add a title to download the file.
Google, Outlook, and Yahoo open the event in the browser. Reminders are in the file.
- Outlook
- Yahoo
How to create an ICS file
Fill in the title, the place, the meeting URL, the time zone, and the start and end. ICS means iCalendar, the format in RFC 5545. The download uses that format and the .ics extension.
Choose a repeat if the event happens again. Leave the count empty when it should continue. Set a count when it should stop. A reminder is written into the file. The web links under the download do not include that reminder.
Download event.ics. On a computer, double-click it and the default calendar app shows the event ready to add. On a phone, open the file from a message and pick a calendar.
Share the file as an email attachment, or host it and send the link. Apple Calendar uses this download. It does not have a separate web compose URL.
What people use it for
A webinar can carry the meeting URL and a reminder so the guest is notified before the session starts.
A recurring meeting can be weekly or monthly, with a join link in the event URL. Leave the count empty when the meeting has no planned last date.
A birthday or anniversary is a yearly event. A reminder one day or one week before is stored in the file.
A class schedule can be the same file sent to every student. Each person imports it into the calendar they already use.
A conference or a talk can put the room in the location and a live-stream URL in the event URL.
A one-off appointment can include the address, a confirmation note in the description, and a reminder. Most apps ignore a file attached inside the ICS itself, so put documents behind a normal link.
Repeat rule and reminder
The file can carry a daily, weekly, monthly, or yearly repeat, and a reminder as a VALARM. A reminder is written only into the file.
What a downloaded file does not do
Importing the file adds that event on the calendar that opens it. It does not keep another Microsoft 365 tenant's free/busy up to date. That gap is explained in why a subscribed ICS feed does not count as Busy.
Questions
What is an ICS file?
ICS is the file extension for iCalendar, the format in RFC 5545. An iCal file, an .ics file, and an iCalendar file are the same thing. Google Calendar, Outlook, and Apple Calendar all import it.
Do I need an account?
No. The file is built in your browser. OnlyBusy does not receive the event, and there is no signup.
How many times can it repeat?
Set a repeat count, or leave the count empty so the event repeats without an end. Daily, weekly, monthly, and yearly are the frequencies. A count of four with a weekly rule is four occurrences.
Where do reminders go?
A reminder is a VALARM block inside the file. One day before is written as a one-day trigger, and one week before is written as a one-week trigger. Google, Outlook, and Yahoo web links do not carry that reminder.
Can I attach a file inside the event?
Most calendar apps ignore attachments inside an ICS file. Put a public link, such as a document URL, in the description or the event URL instead.
How do I open it?
On a computer, double-click the file and the default calendar app offers to add it. On a phone, open the file from email or messages and pick a calendar. Google Calendar can also import it from Settings, Import and export.
Writing a private Busy block into someone else's Outlook or Google calendar is a different job, covered in show busy on Google Calendar and Outlook without sharing the event.