Open ICS File

Information, tips and instructions

Open ICS File

ICS file extension is used by iCalendar internet standard to store events, to-dos, free/busy information and journal entries. The ICS file format is defined in RFC-5545 specification.

iCalendar is a protocol independent standard. It means that events could be shared using different transports including e-mail, HTTP protocol and others.

To open ICS file online or offline you can either use a calendar application of your choice or if you don’t have one you can open ICS file in a text editor and view information inside. Since information in iCalendar file format is stored as plain text it is possible to interpret information inside ICS file without special software. But it is still recommended to use one of the available calendar applications since they can read information in ICS file and display it in an easy to understand way. Editing calendar data in a specialized software is also much easier.

To convert ICS file to CSV format you can use the ICS to CSV conversion tool that we created using Javascript. At this moment it is capable of writing VEVENT information with all attached fields to the CSV file. You can customize which fields you want to output.

iCalendar standard is used by many online internet calendaring and scheduling applications including:

To display iCalendar events in HTML pages hCalendar microformat was developed. Using hCalendar microformat on a web page allows any software which parses the page to correctly read and interpret calendar events information. There are two different microformats for displaying iCalendar information. One is hCalendar which is based on “span” and “abbr” HTML tags. The other one is microformats2 update which uses “time” HTML tag. Microformats2 version is considered more suitable because of accessibility problems with original hCalendar version.

Besides ICS file extension iCalendar also uses IFB file extension to store information about free/busy time.

iCalendar is based on vCalendar created by the Internet Mail Consortium (IMC). vCalendar used VCS file extension for calendar data transfer.

Below is an example of calendar data file stored in iCalendar file format:
PRODID:-//hacksw/handcal//NONSGML v1.0//EN
UID:[email protected]
ORGANIZER;CN=Test User:MAILTO:[email protected]
SUMMARY:Test Event

Open ICS File on Windows OS

  • Try double clicking on a ICS file in Windows File Explorer.
  • If the ICS file opener software is associated correctly then the file will open
  • If the file did not open you should install Microsoft Outlook software
  • To open ICS file in Microsoft Outlook you need to launch it, go to the default calendar and then select File->Import/Export in the main menu
  • In the Import/Export dialog select "Import an iCalendar" file, select the file and click "Import"

Open ICS File on Mac OS

  • Double click on a ICS File in Mac OS Finder.
  • If ICS file was formed correctly then Apple Calendar will open.
  • Select calendar to which you want to add the event (typically it will be Home or Work).
  • You will see your calendar opened at specific date with an event details diplayed. If needed you can click on the event details and copy information about the event. You can also send an email to the event originator.

ICS files are transferred over e-mail or internet using text/calendar multipurpose internet mail extensions (MIME) type.