IntlRelativeDateTimeFormatter: "3 Days Ago" in Any Locale

Weilin Du opened the vote on October 7, 2026. Voting closed on October 22 with 25 votes for, none against and no abstentions. The RFC needed a two-thirds majority, and it passed unanimously.

Apps show strings like "3 days ago", "in 2 weeks", "yesterday" and "next Sunday" all the time. PHP has no built-in way to produce them in every language. Developers often write their own plural rules, unit names and word order. Weilin Du announced the RFC on internals to add an IntlRelativeDateTimeFormatter class to the intl extension, using ICU's existing relative date formatter.

How it works#

You create a formatter for a locale, then pass it a number and a unit:

$formatter = new IntlRelativeDateTimeFormatter('en_US');

echo $formatter->format(-1, IntlRelativeDateTimeFormatterUnit::Day);
// yesterday

echo $formatter->format(2, IntlRelativeDateTimeFormatterUnit::Week);
// in 2 weeks

echo $formatter->formatNumeric(-1, IntlRelativeDateTimeFormatterUnit::Day);
// 1 day ago

Negative numbers mean the past and positive numbers mean the future. format() uses words like "yesterday" when the locale has them. formatNumeric() always uses a number. The formatter accepts weekday units, too, so you can request phrases such as "last Sunday".

The RFC also adds three pure enums for styles, capitalization contexts and units. An optional NumberFormatter controls numeric output. combineDateAndTime() joins a relative date and a time. Error accessors match other intl classes. The API does not accept a date or timestamp, and it does not choose the unit for you. Your code still decides between "in 7 days" and "in 1 week".

What it means for existing code#

The change adds one class and three enums in the global namespace. Existing intl behavior does not change, but userland classes with those names could clash when intl is loaded. The implementation was merged into php-src on October 22, 2026, so it ships in PHP 8.7.