Project 50, Developer tools

Temporal Date and Time Toolkit

Convert a meeting time across cities, count the days until a deadline, or decode a Unix timestamp. Temporal fixes the old Date object's time zone headaches.

Main API: Temporal
Fallback: temporal-polyfill 1.0.5
Dependencies: Polyfill only when needed
Your browser: Checking

Date and time tools

Loading Temporal

Date and timeIn this zoneAdd a city

Unix timestamp

Or a date and time (UTC)

How it works

Use the right typePlainDate for calendar days, ZonedDateTime for a moment in a place, Instant for an exact point on the timeline.
Convert zonesOne ZonedDateTime is moved to other zones with withTimeZone(). The clock time changes, the moment does not.
Do math safelyuntil() and add() understand months of different lengths and daylight saving, so 1 month after 31 January is 28 or 29 February.

import { Temporal } from "https://cdn.jsdelivr.net/npm/temporal-polyfill@1.0.5/+esm"; // only if not built in

const meeting = Temporal.ZonedDateTime.from("2026-10-26T09:00[America/New_York]");
meeting.withTimeZone("Asia/Dhaka").toString();   // 2026-10-26T19:00:00+06:00[Asia/Dhaka]

const until = Temporal.PlainDate.from("2026-09-23").until("2026-12-25", { largestUnit: "month" });
until.toString();                                // "P3M2D": 3 months, 2 days

Temporal.PlainDate.from("2026-01-31").add({ months: 1 }).toString(); // "2026-02-28"