Interface

The interface of Google Calendar, designed by Kevin Fox (who also designed Gmail and the second version of Google Reader^[2]), is similar to desktop calendar applications such as Microsoft Outlook or iCal on Mac OS X. The Ajax-driven interface enables users to view, add, and drag-and-drop events from one date to another without reloading the page. It supports view modes such as weekly, monthly, and agenda. Users can "quick add" calendar events by typing standard English phrases, such as "Dinner with Michael 7pm tomorrow". Users can also set the number of days to show in their custom view mode.

Content access

Events are stored online, meaning that the calendar can be viewed from any location that has Internet access. In the case of a user experiencing a hard drive failure, it also means that no data is lost. The application can import Microsoft Outlook calendar files (.csv) and iCalendar files (.ics), the de facto open calendaring file format), although at this stage only when the fields are all in U.S. format.^{[citation needed]} Multiple calendars can be added and shared, allowing various levels of permissions for the users. This enables collaboration and sharing of schedules between groups. General calendars available for importing into one's account include those containing national holidays of various countries.

Sharing calendars

Google Calendar allows multiple calendars to be created and shown in the same view. Each can be shared, either read-only or with full edit control, and either with specified people or with everyone (public calendars). In February 2009, Google discontinued the option of searching for public calendars from the search field by removing the "Seach Public Events" button. It also disabled its public calendar gallery,^[3] citing maintenance and usability issues. The company suggests adding calendars via the "Interesting Calendars" feature, known calendar URLs, or via email requests to friends.

Device synchronization

Currently, Google Calendar can be synchronized with mobile devices (e.g., BlackBerry, Palm, iPhone, Pocket PC) or with PC applications (e.g., Microsoft Outlook) via third party software, and natively with Apple's iCal (workarounds required for iCal 3.x, full functionality with iCal 4.x). Google Calendar is natively supported on Android -based mobile phones such as the T-Mobile G1 and the Motorola CLIQ. Event reminders can be sent via email, as well as via SMS to mobile phones in over 80 countries and regions.

Google integration

Google Calendar is integrated with various other Google services:

• Gmail, Google's webmail service. When an e-mail that contains trigger words (such as "meeting", or dates and times) arrives, an "add to calendar" button is automatically displayed alongside it.
• iGoogle, the user-designed Google homepage, in which users can choose and organize content in the form of "gadgets". The calendar is shown as a module on your homepage. This "gadget" offers options to edit how the time is displayed, which day the week starts on, and a link to "Add Event".^[4]
• Google Desktop, Google's desktop search software for Windows or Mac OS X. The mini-calendar gadget allows you view your agenda without having to open your browser. You can place it on your desktop or leave it docked in the sidebar.^[4]

SMS updating via GVENT codes

For supported mobile carriers in the United States, the GVENT feature of Google Calendar allows users to create new events and check calendar information via SMS.^[5]

2009 Introduction

On March 4, 2009, Google Calendar began offering offline support.^[6]
On May 13, 2009, Google Calendar began offering to-do lists.^[7][8]