ICS Calendar Plugin

Using a simple shortcode, you can turn any iCalendar subscription (ICS) feed (Google Calendar, Microsoft Office 365, Apple iCloud, Airbnb, Vrbo, and many more) into a seamlessly integrated, auto-updating, zero-maintenance WordPress calendar.

Continue to manage your events in the calendar software you’re already using! You’ll automatically have an up-to-date calendar in your WordPress website with no extra work.

Display your calendar in month, list or week view. Many additional customization options are available. See our User Guide for full details.

No API keys required!

Works with ANY calendar software that generates a public iCalendar subscription link.

Live Preview

You can preview your own calendar in any ICS Calendar view at our website: icscalendar.com/preview

Shortcode Builder

We’ve made it easier than ever to get started using ICS Calendar with our new online shortcode builder: icscalendar.com/shortcode-builder

Language Support

All date strings (days of the week, months, etc.) are automatically translated into your site’s configured language (under Settings > General > Language) and date/time formats using core WordPress functionality. All text content for the calendar itself is displayed as-is from the feed.

The small amount of additional front-end displayed text generated by the plugin defaults to U.S. English, but also supports the following translations: Chinese, Danish, Dutch, Estonian, Finnish, French, German, Greek, Hungarian, Italian, Japanese, Korean, Latvian, Lithuanian, Norwegian, Polish, Portuguese, Russian, Spanish and Swedish.

Please contact us if you would like us to add support for your language!

This plugin includes the PHP ICS Parser library by Jonathan Goode, John Grogg and Martin Thoma (MIT license).

Once the plugin is installed and activated, use the shortcode below (adding your own ICS feed URL between the quotation marks) to insert a calendar into your pages. Use our online Shortcode Builder to easily create a customized shortcode, or consult the User Guide for more information.

[ics_calendar url=""] 

Be sure you are using the iCalendar subscription (ICS) URL (i.e. for importing into a calendar program), not the URL for viewing a calendar in a web browser. To test if you have the correct URL, paste it directly into your browser address bar. It should download an .ics file, not display the calendar in the browser.

11.3.2.1 – 2024.07.19

• Changed names of settings actions to replace admin_options with settings for consistency with changes in 11.3.2.
• Modified logic in some calendar rendering functions to prevent them from running unnecessarily and slowing down the Block Editor.
• Removed a conditional that treated events spanning two days, with start and end times, as one-day events rather than multi-day events. This older logic was obviated by subsequent changes in the plugin’s handling of multi-day events, but some users may be expecting the previous functionality. Please use the WordPress Support Forums to report any issues.

11.3.2 – 2024.07.08

• Renamed and relabeled “admin-options” to “settings” for consistency and clarity in future code updates.
• Added Increase memory limit when rendering calendars setting, to allow for adjusting the system memory limit specifically when parsing calendar data. (Also added related r34ics_memory_limit_mb() and r34ics_memory_limit_select() functions.)
• Bug fix: Added missing r34ics_display_calendar_event_item filter on certain multi-day events.
• i18n: Updated translation strings.

11.3.1 – 2024.07.03

• jQuery:
  • Modified the r34ics_init_start and r34ics_init_end custom events to pass an elem parameter, containing the DOM object that called the r34ics_init() function. On calendars not loaded via AJAX, the function runs on initial page load, and the value passed is null. When the calendar is loaded via AJAX, the object is the div.r34ics-ajax-container element for that calendar. This allows custom functions using this event to have access to the properties of the DOM element, including the id attribute, so developers can write calendar-specific JavaScript.
• Miscellaneous:
  • Standardized all checks for ICS Calendar Pro to use class_exists() and removed some ICS Calendar Pro-specific JavaScript by using the r34ics_init_end event.
• i18n: Fixed incorrect text domain for translation strings in admin sidebar, and updated affected translation files.

11.3.0.1 – 2024.06.27

• Updated admin page to address possible issue of tabs not working.
• Added new plugin settings to System Report.
• Added r34ics_raw_feed_strip_dtend_none() function (using the r34ics_display_calendar_preprocess_raw_feed filter) to handle edge cases where feeds include the invalid DTEND:None. (This is an identified issue with easyVerein calendars.)

11.3.0 – 2024.06.13

• Admin:
  • Fixed minor issue with ICS Feed URL Tester changes in version 11.2.2 that prevented display of the tested URL after submitting.
  • Reorganized Settings tab with options grouped under subheadings.
• Basic Authentication:
  • Added support for including HTTP Basic Authentication user/pass parameters directly in the feed URL in the shortcode, in addition to the previous constant-based method. This approach is still discouraged, since it involves putting the credentials directly in the shortcode and could potentially expose those credentials publicly if the plugin is deactivated, since WordPress outputs the text of any undefined shortcodes directly on the page. But considering that HTTP Basic Authentication is inherently insecure, this should not be a significant issue in most cases. If you are concerned about the confidentiality of your basic auth credentials, please continue to use the old approach. (Note: This change only applies to the new feed request method introduced in version 11, so it will not work if the Use legacy feed request method option is turned on. When using the legacy method, you must use the basicauth parameter in conjunction with the R34ICS_FEED_BASICAUTH constant in your wp-config.php file.)
• CSS:
  • Modified CSS for new feedlabelindesc so feed color dot only appears in event details hover box, and not in inline descriptions; added styling for feed labels in lightbox.
• Developer:
  • Added r34ics_display_calendar_event_item filter. This filter runs immediately before a parsed event gets added to the data array for the calendar, allowing you to modify any event details as needed. This is very similar to our second example use case for the existing r34ics_display_calendar_filter_ics_data filter, minus the need for five nested foreach loops!
• Event details hover/lightbox:
  • Moved recurrence description to top, below time.
  • Changed HTML wrapper for img from div to figure.
• Miscellaneous:
  • Changed language code in iCalendar output for eventdl to reflect site locale instead of hardcoding EN.
• Vendors:
  • Updated embedded ics-parser library to latest version (3.4.0+, up through commit 7286ce0.)
• i18n: Updated translation strings.
• Bumped ‘tested up to’ to 6.6.

11.2.2 – 2024.06.07

• Admin:
  • ICS Feed URL Tester enhancements. Added suggestions for handling some common situations that may cause a feed request to fail or return incorrect results.
  • CSS refinements.
  • Fixed a bug that caused ICS Feed URL Tester to always return an unknown error after changes introduced in version 11.1.0.
  • Updated action links on Plugins page.
• Shortcode:
  • Added feedlabelindesc parameter and related functionality.
• Miscellaneous:
  • Added R34ICS::shortcode_feed_array_params property and logic to split pipe-delimited, feed-related parameters into arrays for easier logic elsewhere, plus related functionality, including r34ics_shortcode_feed_array_params filter. (This is used by feedlabelindesc and may be used by other future enhancements.)
  • Modified r34ics_has_desc() function to support feedlabelindesc.

11.2.1 – 2024.05.30

• Shortcode:
  • Added eventlocaltime parameter. Will display all times in the local timezone of the individual event, if applicable. Note: When this parameter is used, the timezone abbreviation T will automatically be appended to the timeformat parameter while parsing the shortcode.
  • Added support for T (timezone abbreviation) in timeformat parameter. Note: Currently only supports placing T at the end of the string. (The timezone abbreviation will be inserted at the end of the time output, regardless of where T appears in the timeformat string.)
• Admin:
  • Reordered Settings tab items.

11.2.0 – 2024.05.29

• Admin:
  • Fixed issue after introduction of tabbed layout on ICS Calendar admin page that would cause the wrong tab to load after clicking buttons on the Utilities tab.
  • Added “System Report” link in sidebar.
• Shortcode:
  • Added fulldateintable parameter. By default, month and list views show only the day number in the table on desktop breakpoints, and use the date format defined by the format parameter for mobile breakpoints. When fulldateintable="true" is set, the format value will be used to display the date in the table on desktop as well.
• Miscellaneous:
  • Added check for R34ICS class already being defined, to prevent a potential fatal error on plugin activation.
  • Added list of valid view names to allow fallback to month view if an invalid name is used. Use the new r34ics_views filter to add any custom view template names to the list.
  • Modified loading logic to run r34ics_update() if the version number has changed, not just if it has increased.
  • Updated protected properties of the R34ICS class.
• Hotfix:
  • Modified CSS to prevent display of AJAX “loading” animation being stuck after the calendar loads.

11.1.0 – 2024.05.22

• Admin:
  • Redesigned admin screen with tabbed layout for improved usability, relabeled some elements, and updated links to User Guide documentation. Refactored associated code into discrete methods. Removed legacy JavaScript that was no longer in use.
• AJAX:
  • Added new Always use AJAX to render calendars admin setting. This will automatically force all calendars on the site to render asynchronously using AJAX.
  • Restructured AJAX rendering and added a JavaScript interval to automatically refresh all AJAX-loaded calendars on the same frequency as the site’s configured Transient (cache) expiration setting. (Minimum of 300 seconds.) Provides a way for pages containing calendars to be left open indefinitely (e.g. for kiosk displays) and receive updates.
• Parameters:
  • Added new hidecancelledevents and hidetentativeevents shortcode parameters. These hide events with a STATUS value of CANCELLED or TENTATIVE, respectively.
• Miscellaneous:
  • Added fallback to get event URL from the URI property if it exists. The iCalendar spec includes a URI property, but not a URL property. However in our practical experience the URL property is commonly used by calendar vendors.
  • Replaced several instances of null coalescing operators (?? null) with short ternary operators (?: '') setting empty strings rather than null values for event properties. This should not produce any noticeable changes in most cases, but may occasionally allow for values to be returned that have been missing in the output under the old logic.
  • Updated the set of fields that are masked by the maskinfo parameter to account for changes in the ics-parser library.
• i18n: Updated translation strings.

11.0.1.2 – 2024.05.15

• Added R34ICS::get_list_style_views() and r34ics_list_style_views filter to allow external addition of list-style views for certain conditional logic.
• Performance improvements: Narrowed rough parsed date ranges defined in R34ICS::display_calendar_date_range() to reduce memory usage and processing time for calendars with a large number of recurring events.
• Admin page layout adjustments.
• Debugging: Removed restriction that only reports dynamic peak of memory usage if debug level is set to 2 or higher.
• Bumped ‘tested up to’ version to 6.5.3.

11.0.1.1 – 2024.05.02

• Developer:
  • Added r34ics_display_calendar_after_args action.

11.0.1 – 2024.05.02

• Basic/list views:
  • Pagination: changed default pagination count to 5 instead of using posts_per_page site option; cast pagination value as integer when set; fixed missing # in previous/next pagination URLs. Fixed two jQuery bugs.
• Week view:
  • Modified change from version 11.0.0.3 to adapt when the window is resized between phone and non-phone breakpoints. (The previous fix depended on the size of the window on initial page load.)
• Admin:
  • Added r34ics_is_block_editor() function, and logic to prevent unnecessary processing potentially occurring on Block Editor screens.
• Developer:
  • Added two new actions: r34ics_shortcode_before_display_calendar and r34ics_shortcode_after_display_calendar. These actions fire off in R34ICS::shortcode() before and after the call to R34ICS::display_calendar().
  • Corrected add_action() to add_filter() for r34ics_display_calendar_exclude_event in class-r34ics.php.
• Miscellaneous:
  • Removed logic to run gzdecode() in R34ICS::_url_get_contents() because wp_remote_get() already does that. Eliminates appearance of numerous related PHP warnings in log files.

11.0.0.3 – 2024.04.23

• Week view:
  • Fixed JavaScript issue of containers not extending to the full width in mobile “list”-style layout when switching between weeks.
• ICS feed request functionality:
  • Updated R34ICS::_url_get_contents() to address some additional edge case issues introduced with the switch to wp_remote_get() in version 11.0.0 that were not fully resolved by the 11.0.0.1 update. Specifically, added customized handling of 301 and 302 redirects to use the Location header returned in the response object, rather than relying on the built-in redirection in wp_remote_get(), which was causing some hosts (including Google Calendar) to reject the request.
  • Added Use legacy feed request method option on settings page, and corresponding R34ICS::_url_get_contents_legacy() method. For sites that are still not successfully retrieving feeds with the fixes added in 11.0.0.1, this option reverts to using the old method for requesting feeds using cURL and fopen functions.
  • Updated debugging tools for internal testing during development.

(Note: Version 11.0.0.2 was intentionally removed due to a logistical issue.)

11.0.0.1 – 2024.04.18

• Fixes an issue with HTTP headers in the new method of retrieving ICS feeds. The issue was hotfixed approximately one hour after the initial release, but some sites may have picked up the update within that hour. This update also increases the timeout from 5 to 30 seconds, to address potential issues with retrieving very large ICS files.

11.0.0 – 2024.04.18

PLEASE NOTE: This version includes a significant rewrite of the function that retrieves the contents of ICS feed URLs. It is now using the built-in wp_remote_get() WordPress function (instead of PHP cURL and fopen functions as before), so it should be fully compatible with all existing installations. However, if you encounter any new issues, please visit the WordPress Support Forums for assistance.

• Admin Settings:
  • Added Allow access to these hostnames that resolve to reserved IP addresses setting. This allows sites to access calendar servers on the same physical IP address as the web server, or within the same internal network. Previously this needed to be handled using custom PHP code as outlined in this blog post.
• Code Refactoring:
  • Replaced previous cURL and fopen logic with wp_remote_get() in R34ICS::_url_get_contents() method. Correspondingly, deprecated the curlopts and method parameters. Note: The second and fourth parameters of the protected method R34ICS::_url_get_contents() were removed rather than deprecated. No external plugins should be using this method other than ICS Calendar Pro, which has been correspondingly updated.
  • Removed admin notice checking for presence of cURL or fopen functions.
• WordPress Playground:
  • Added r34ics_is_playground() function to detect if running in WordPress Playground.
• Miscellaneous:
  • Added missing fourth parameter to r34ics_event_description_html action.
  • Changed Room 34 Creative Services logo link on admin page sidebar.
  • Fixed PHP warning in r34ics_system_report() in rare situations where get_option('active_plugins') returns a plugin that is not included in get_plugins(). (May occur if the plugin has been manually removed from the file system.)
  • Modified R34ICS::event_description_html() to handle $event['start_time'] and $event['end_time'] as alternatives to $event['start'] and $event['end'].
  • Updated header details in ics-calendar.php.
• a11y:
  • Changed CSS for .ics-calendar-arrow-nav > *.inactive to completely hide inactive arrow navigation elements (e.g. “Previous” while on first month, “Today” while on current month, etc.) rather than screening back their opacity. Modified jQuery corresponding to these elements to dynamically add aria-hidden="true" when inactive class is added.
• i18n:
  • Added and updated translation strings.
• Bumped ‘tested up to’ version to 6.5.2.

Full Changelog

Changelog truncated here due to WordPress repository requirements. Please see changelog.txt for older logs.