April 23rd, 2024

[ Breaking Change ] Carbon diffIn methods updated

[ Breaking Change ] Carbon diffIn methods updated

Carbon has recently rolled out significant changes in its version 3.0, particularly affecting the diffIn* functions. These changes mark an important shift in how we as developers will be handling date and time differences in our apps.

Understanding the Change

Historically, Carbon's diffIn* functions provided an integer output representing the difference between two dates or times. These functions were straightforward but lacked the precision necessary for more complex calculations, such as those needed in financial applications or detailed time tracking systems.

In Carbon version 3.0, these functions now return float values by default. This change enhances the precision of time difference calculations, allowing us to capture subtleties down to the millisecond. Furthermore, the update brings another critical adjustment: the new diffIn* functions calculate differences based on timestamps, thus ignoring adjustments like Daylight Saving Time. This adjustment ensures that the time differences are absolute, providing more consistency across different time zones and DST transitions.

The affected methods are: diffInDays diffInDaysFiltered diffInHours diffInHoursFiltered diffInMicroseconds diffInMilliseconds diffInMinutes diffInMonths diffInQuarters diffInSeconds diffInUnit diffInWeekdays diffInWeekendDays diffInWeeks diffInYears

Adapting to Carbon v3.0

These changes necessitate a review and potential modification of existing codebases. Applications that relied on integer outputs for scheduling, comparisons, or accumulations might now face issues with type mismatches or unexpected results due to the precision of float values.

One of the most significant challenges is ensuring that older applications continue to function correctly without extensive refactoring.

Best Practices Moving Forward

  • Review Existing Code: Audit any code that uses Carbon's diffIn* functions. Understanding how these changes impact your application's logic and output is crucial.
  • Embrace Precision: Where precision in time calculations is beneficial, embrace the new float outputs to enhance the functionality of your applications.
  • Handle DST Carefully: Given that the new functions ignore Daylight Saving Time adjustments, we need to handle these changes manually if they affect our application's logic.
  • Community Engagement: Participate in community discussions on platforms like GitHub to share experiences, solutions, and get help adapting to the new version. The Carbon GitHub page is a good start for engaging with other developers facing similar challenges.
  • Continuous Learning: Keep abreast of updates in the documentation and future changes to Carbon. Understanding the library's roadmap can help anticipate further changes and prepare accordingly.


While the transition to the new version of Carbon may pose challenges, it also presents an opportunity for growth and improvement in how we handle date and time computations in PHP. As the community adapts and refines best practices around these changes, the enhancements in precision and consistency will likely become invaluable in developing more robust and reliable applications.

Statamic Ninja


Marian Pop

PHP / Laravel Developer. Writing and maintaining @LaravelMagazine. Host of "The Laravel Magazine Podcast". Pronouns: vi/vim.

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