ICS file
An ICS file (Internet Calendar Scheduling) is a standardised calendar file format that contains event details such as the date, time, location, description, and organiser, which can be opened by any major calendar application including Google Calendar, Apple Calendar, and Microsoft Outlook. The format is supported across all major operating systems, devices, and calendar tools, making it the most reliable way to ensure recipients can save an event to their calendar regardless of which platform they use.
In email marketing, ICS files are commonly used in event invitation emails, webinar registration confirmations, and appointment confirmation sequences. Including an ICS file, or a prominent ‘Add to calendar’ button that triggers one, dramatically increases the likelihood that a registered attendee will actually attend the event. The event becomes visible in their calendar alongside all their other commitments, rather than being buried in an email they may not find again when the date approaches.
For B2B event marketers, the ICS file is a small but high-impact element of the event communication workflow. It should be included in the initial confirmation email and optionally in reminder emails sent in the days before the event. The ICS file should contain accurate details: the correct date, time, timezone, location or virtual meeting link, and a brief description that reminds the registrant what they signed up for and why it is worth attending.
How do I include an ICS file in an email?
Most email marketing platforms and webinar tools generate ICS files automatically for event registration confirmation emails. If you are building this manually, you create an ICS file with the correct event details and either attach it to the email or host it on a URL and link to it. An ‘Add to calendar’ button in the email that links to the hosted ICS file is the most user-friendly approach, as it works across all devices without requiring the recipient to handle an email attachment.
What information should an ICS file contain?
A well-formed ICS file for an event should include the event title, start and end date and time in the correct timezone, the location or virtual meeting URL, a description of the event, and the organiser’s name and email address. For webinars, the meeting link belongs in the location or description field so it is accessible directly from the calendar event without needing to search for the original confirmation email.
What is the difference between an ICS file and a calendar invite?
A calendar invite is a real-time invitation sent directly from one calendar system to another, typically used for one-to-one or small-group meetings such as a sales call booked through a scheduling tool. An ICS file is a portable calendar file that can be downloaded and imported into any calendar application, making it suitable for one-to-many event promotions where you want registrants to save a date without requiring direct calendar access. ICS files are the standard format for marketing event confirmations.