iCalendar is the standard Internet format for exchanging calendar information. iCalendar is used and supported by a large number of products, including Google Calendar, Apple Calendar and Reminders (formerly iCal), Microsoft Outlook, Yahoo! Calendar and the Lightning extension for Mozilla Thunderbird.

Follow these steps to export a project as an iCalendar file (.ics):

The exported calendar contains to-dos (VTODO items created from tasks) and events (VEVENT items created from time entries). However, not all applications are able to import both types of items because not all of them are 100% compatible with the iCalendar format. Most applications can import events but only some of them can import to-dos.

Here are two scenarios where exporting a project as an iCalendar file might be helpful.

Scenario 1: Share a project with a client using Apple Calendar and Reminders

OS X (10.8 and later) has two applications that can import iCalendar files: Calendar and Reminders (formerly iCal). Apple Calendar imports only events (time entries) while Apple Reminders imports only to-dos (tasks).

Once you import an iCalendar file in Apple Calendar you can visualize your time entries using the calendar views of the application. If you store your calendars in iCloud, you can also share them with a client who needs to know what you did.

When you import an iCalendar file in Apple Reminders you can see which tasks are done, which ones are in progress and when they are due. If you store your reminders list in iCloud, you can access it from iPhone or share it with a client.

Scenario 2: View your work using Google Calendar

Google Calendar can import events from iCalendar files. This means that you can import in Google Calendar the time entries recorded on a project so you can have a better look at what you did. You can also share a calendar with other people who need to know what you did.