JavaScript Temporal PlainDateTime
JavaScript Temporal.PlainDateTime Reference
Revised March 2026
The Temporal.PlainDateTime Object
The PlainDateTime() objects ios a temporal date and time object.
It represents a calendar date and a wall-clock time with no time zone.
Example: 2026-05-07T14:30:00.
Note
A PlainDateTime is essentially the combination of a Temporal.PlainDate() and a Temporal.PlainTime().
Temporal.PlainDateTime Methods
| Method | Description |
|---|---|
| from() | Returns a new PlainDateTime object from another object or a string |
| toPlainDate() | Returns a new PlainDate object |
| toPlainTime() | Returns a new PlainTime object |
| toZonedDateTime() | Returns a new ZonedDatetime object |
| with() | Returns a new PlainDateTime with specified fields modified |
| withCalendar() | Returns a new PlainDateTime with a different calendar system |
| withPlainTime() | Returns a new PlainDateTime the time part replaced by a new time |
| Arithmetic | |
| add() | Returns a new PlainDateTime with a duration added |
| subtract() | Returns a new PlainDateTime with a duration subtracted |
| round() | Returns a new PlainDateTime rounded to a given unit |
| Comparison | |
| compare() | Returns -1, 0, or 1 from comparing two dates |
| equals() | Returns true if two PlainDateTime objects are identical |
| since() | Returns the difference from another date |
| until() | Returns the difference until another date |
| Formatting | |
| toString() | Returns an ISO 8601 string representation |
| toJSON() | Returns an ISO 8601 string for JSON serialization |
| toLocaleString() | Returns a language-sensitive representation of the date |
| valueOf() | Throws a TypeError (prevents temporals from being converted to primitives) |
Temporal.PlainDateTime Properties
The Temporal.PlainDateTime object has 22 properties of calendar date information.
| Property | Description |
| calendarID | Calendar system identifier ("iso8601") |
| day | The day as an integer (1-31) |
| dayOfWeek | The day of the week as an integer (1 = Monday) |
| dayOfYear | The ordinal day of the year |
| daysInMonth | The total number of days in that month |
| daysInWeek | The total number of days in that week |
| daysInYear | The total number of days in that year |
| era | The era name of the calendar, if applicable ("gregory") |
| eraYear | The year within the era, if applicable |
| hour | The hour as an integer (0-23 |
| inLeapYear | A boolean indicating if the date falls in a leap year |
| microsecond | The microsecond as an integer (0-999) |
| millisecond | The millisecond as an integer (0-999) |
| minute | The minute as an integer (0-59) |
| month | The month as an integer (1-12) |
| monthCode | A calendar-specific string code for the month ("M01") |
| monthsInYear | The total number of months in that year |
| nanosecond | The nanosecond as an integer (0-999) |
| second | The second as an integer (0-59) |
| weekOfYear | The week number within the year |
| year | The year as an integer |
| yearOfWeek | The year that the week belongs to |
Browser Support
Temporal is a major update to the JavaScript standard (TC39).
It is currently fully supported in Chrome, Edge, and Firefox, and is expected to reach full availability across browsers throughout 2026.
| Chrome 144 |
Edge 144 |
Firefox 139 |
Safari |
Opera |
| Jan 2026 | Jan 2026 | May 2025 | 🚫 | 🚫 |
Opera Support
Opera support will probably appear 1-3 browser cycles after Chromium, which often means a few months later.
Safari Support
As of March 2026, Safari has not yet announced a confirmed release date for stable support of the JavaScript Temporal API.
However, the implementation is actively in development and can be tested today in Safari Technology Preview by enabling the --use-temporal runtime flag.
Polyfill
Until Opera and Safari supports Temporal natively, use the official polyfill.
This Polyfill allows Temporal code to run in all browsers today:
Example
<script
src="https://cdn.jsdelivr.net/npm/@js-temporal/polyfill/dist/index.umd.js">
</script>
<script>
// Now you can use Temporal
const today = Temporal.Now.plainDateISO();
</script>
