How to use the add to calendar link generator
- Enter the event title and the start and end date and time, or tick All day event.
- Choose a time zone: each viewer's own zone, UTC, or one of the named US zones. Add a location and description if you like.
- Read the Google Calendar, Outlook.com and Microsoft 365 links and the .ics file. Test each link with the open button.
- Copy the links for your website or email, or download the .ics file to attach.
A lunch on June 1, 2025
An event called Team lunch on 2025-06-01 from 10:00 to 11:00, with no zone chosen, gives a Google link that contains dates=20250601T100000/20250601T110000. Those are floating times: they show as 10:00 to 11:00 on the viewer's own clock.
Choosing Eastern (New York) converts the time to UTC, because New York is on daylight time on June 1 (4 hours behind UTC), so 10:00 becomes 14:00 UTC and the link carries dates=20250601T140000Z/20250601T150000Z. For an event on January 15 the offset is 5 hours, so 10:00 becomes 15:00 UTC.
The link formats
The Google link is calendar.google.com/calendar/render with action=TEMPLATE, a text title, dates as start and end in the form YYYYMMDDTHHMMSS separated by a slash, and optional details and location. A time ending in Z is in UTC. An all day event uses dates without a time, and the end date is the day after the last day, because the end of an all day range is not included.
The Outlook.com and Microsoft 365 links are outlook.live.com and outlook.office.com deep links with subject, startdt and enddt in ISO form, plus body and location, and allday set to true for all day events. Every parameter is percent encoded. These layouts are commonly used for add to calendar buttons but are not promised by the services, so test each link before you publish it.
The .ics file
The file follows the iCalendar format. It holds one event with a unique ID, the time the file was made, the start and end, the title, and the location and description when given. Commas, semicolons, backslashes and line breaks in text are escaped, long lines are folded at 75 bytes without splitting a character, and lines end with a carriage return and line feed, as the format requires. Without a time zone the times are floating. With one, they are written in UTC.
Nothing is uploaded and no invitation is sent. Daylight saving time is applied from your browser's time zone data on the event date. For time zone planning use the time zone converter, for a scannable code use the QR code generator, and see the URL encoder and decoder and the UTM link builder.
Assumptions and limits
- Link formats are the ones commonly used for these services and may change without notice.
- A named zone is converted to UTC using your browser's time zone rules for that date.
- Without a zone, times are floating and appear at the same clock time for every viewer.
- All day events end on the day after the last day in the links and the file, as the formats expect.
Frequently asked questions
How do I create an add to calendar link?
Fill in the event and copy the Google or Outlook link. When someone opens it, their calendar shows the event ready to save.
What is an .ics file?
It is a standard calendar file. Opening it in most calendar apps adds the event. It also works as an email attachment.
Why does the all day end date look one day later?
Calendar formats treat the end of an all day event as the day after it finishes. A one day event on June 1 ends on June 2 in the link.
Do these links work in every calendar app?
No promise can be made. The Google and Outlook formats are commonly used, but the services may change them, so test each one before sharing.