Add Native Support for Persian (Jalali) Calendar in WordPress Core

[dangeraligol]

Hello WordPress Core Team,

I would like to request native support for the Persian (Jalali) calendar to be added to the WordPress Core Date/Time system.

The Persian calendar is used daily by more than 110 million native speakers across Iran, Afghanistan, Tajikistan and diaspora communities worldwide. WordPress has one of the largest user bases in these regions, and many business websites—including e-commerce, booking/reservation systems, government portals and educational platforms—must display dates in the Jalali calendar.

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Reasons for proposing native Jalali calendar support

1. Very large Persian-speaking user base

Persian is one of the most commonly used languages in WordPress installations. Many active sites rely on correct Jalali date handling, especially in:

WooCommerce (order dates, invoices)

Booking / Appointment plugins

Events / Calendar systems

LMS platforms

Government and corporate portals

Native support would greatly improve the experience for millions of users.

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2. Existing solutions (plugins) cause technical conflicts

For more than a decade, Persian users have been forced to rely on external plugins for date conversion. These plugins frequently cause issues such as:

conflicts with WooCommerce date operations

incorrect timestamps

broken booking systems

inconsistency between frontend and backend dates

incompatibility with block editor date components

REST API mismatches

Native support inside Core would eliminate all plugin-level conflicts and ensure consistent behavior across the entire WordPress ecosystem.

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3. Growing platform-level support

Modern operating systems now support the Persian calendar at the system level:

Windows 10 and Windows 11 include a native Persian calendar

Android includes partial Persian calendar support

Unicode CLDR contains Persian locale data (fa-IR) and Jalali date formatting patterns

This shows that global system-level support for the Persian calendar is growing and aligns with WordPress’s internationalization goals.

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4. Aligns with WordPress’s mission of global accessibility

WordPress core already includes built-in support for several calendars and international formats.
Adding Jalali calendar support would significantly enhance accessibility and usability for a major global language community.

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Proposed implementation approach

I am not requesting a change in database storage or UTC behavior.
The proposal is limited to adding a calendar layer within the Date/Time API, similar to how local formats are already handled.

Suggested additions:

1. Add a Jalali calendar option to WP_Locale and date formatting functions.

2. Add Jalali support to the JS date components used in Gutenberg (DatePicker, etc.).

3. Ensure REST API returns consistent date formats when Jalali is enabled.

4. Provide a switch in Settings → General → Site Language to automatically enable Jalali when “Persian (fa_IR)” is selected.

This would preserve backward compatibility while enabling a fully native experience.

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Community support

Multiple discussions over the past years in the Persian WordPress community show high demand for this feature. Many developers have also created third-party patches or polyfills to emulate Jalali behavior.
Consolidating these into a Core-level implementation would benefit millions of current and future users.

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Conclusion

Adding native Jalali calendar support would be a major improvement for WordPress internationalization and would fix many long-standing problems that cannot be resolved at plugin level.

I kindly request the Core team to consider evaluating and discussing this enhancement for inclusion in a future WordPress release.

Thank you for your time and consideration.
We are ready to collaborate, test, and provide any technical assistance needed.

[ocean90]

Hi there and welcome to Trac,

we're already tracking this in #37491, so please follow that ticket for updates.