tzdb

Always up to date time zones for time zone pickers, and the country of any time zone.

import { getTimeZones } from "@vvo/tzdb";

getTimeZones().map((timeZone) => timeZone.currentTimeFormat);
// [..., "-07:00 Pacific Time - Los Angeles, San Diego, San Jose, San Francisco", ...]

• Every IANA time zone, grouped by country and clock, with major cities.
• Current offsets and abbreviations: PDT in summer, PST in winter.
• Every current and deprecated IANA name, so saved values always find their entry.
• Names in any language the browser supports.
• The country of a visitor's time zone, to guess where they are without an IP lookup.
• No dependencies, ESM and CommonJS, TypeScript types.

Always up to date

Every day, a GitHub workflow compiles the latest IANA tz database, takes city populations from GeoNames, tests the result and publishes a new version when something changed.

Current offsets come from the browser or Node.js at runtime. A site that never updates this package still follows daylight saving changes, and agrees with the offsets Intl.DateTimeFormat gives the rest of the app.

Time zone picker

npm add @vvo/tzdb

import { getTimeZones } from "@vvo/tzdb";

const timeZones = getTimeZones();

// Saved values can be any IANA name, like "Asia/Calcutta" or "US/Pacific"
function findTimeZone(name) {
  return timeZones.find((timeZone) => timeZone.group.includes(name));
}

function TimeZonePicker({ value, onChange }) {
  const selected = findTimeZone(value ?? Intl.DateTimeFormat().resolvedOptions().timeZone);
  return (
    <select value={selected?.name} onChange={(event) => onChange(event.target.value)}>
      {timeZones.map((timeZone) => (
        <option key={timeZone.name} value={timeZone.name}>
          {timeZone.currentTimeFormat}
        </option>
      ))}
    </select>
  );
}

Save name in the database: every Intl API and date library accepts it.

To search, match the query against the fields people type:

timeZones.filter((timeZone) =>
  [timeZone.currentTimeFormat, timeZone.countryName, timeZone.abbreviation, ...timeZone.group]
    .join(" ")
    .toLowerCase()
    .includes(query.toLowerCase()),
);

Country of a visitor

import { getCountryCode } from "@vvo/tzdb";

const timeZone = Intl.DateTimeFormat().resolvedOptions().timeZone; // "Europe/Paris"
getCountryCode(timeZone); // "FR"
new Intl.DisplayNames(["en"], { type: "region" }).of("FR"); // "France"

It knows every IANA name, including old ones browsers still return, like Asia/Calcutta. It weighs 4 kB and does not load the time zone list.

API

import {
  getTimeZones,
  getCountryCode,
  rawTimeZones,
  timeZonesNames,
  abbreviations,
  tzdbVersion,
} from "@vvo/tzdb";

getTimeZones(options)

Returns time zones sorted by current offset:

{
  name: "America/Los_Angeles",
  alternativeName: "Pacific Time",
  group: ["America/Los_Angeles", "US/Pacific", "PST8PDT"],
  continentCode: "NA",
  continentName: "North America",
  countryName: "United States",
  countryCode: "US",
  mainCities: ["Los Angeles", "San Diego", "San Jose", "San Francisco"],
  rawOffsetInMinutes: -480,
  abbreviation: "PST",
  dstAbbreviation: "PDT", // only for zones with daylight saving time
  rawFormat: "-08:00 Pacific Time - Los Angeles, San Diego, San Jose, San Francisco",
  currentTimeOffsetInMinutes: -420,
  currentTimeFormat: "-07:00 Pacific Time - Los Angeles, San Diego, San Jose, San Francisco",
  currentAbbreviation: "PDT",
}

Options:

• locale: translates alternativeName, countryName and continentName. With "fr", Los Angeles shows as "-07:00 heure du Pacifique nord-américain - Los Angeles, ...". City names stay as they are.
• includeUtc: adds Etc/UTC, whose group includes UTC and GMT.
• date: computes the current* fields at this date instead of now, like the date of a meeting.
• includeGmtOffsets: adds the fixed offsets Etc/GMT-14 to Etc/GMT+12. As in POSIX, the sign is inverted: Etc/GMT+5 is 5 hours behind UTC.

Zones the browser does not know yet are left out, since Intl could not format dates in them. Runtimes without Intl time zone support get every zone at its standard offset.

getCountryCode(timeZone)

The ISO 3166 country code of an IANA time zone name, or undefined for names without a country like UTC.

rawTimeZones

The same list without the current* fields, sorted by standard offset.

timeZonesNames

Every IANA time zone name from zone.tab.

abbreviations

Long names mapped to abbreviations, like "Central European Summer Time": "CEST". Careful, CST means Central Standard Time (-06:00), China Standard Time (+08:00) and Cuba Standard Time (-05:00).

tzdbVersion

The IANA tz database release behind the data, like "2026e".

Compared to countries-and-timezones

	@vvo/tzdb	countries-and-timezones
Data updates	Every day, automatically	By hand
Current offsets	From the browser, at runtime	Computed when the package was built
Abbreviations that follow DST	Yes	No
Translations	Any language the browser has	No
Country of a time zone	4 kB	9 kB
Picker list with cities and names	17 kB	Not available

Sizes are minified and gzipped. countries-and-timezones weighs 9 kB in total, without cities, display names or abbreviations.

How time zones are grouped

Zones share an entry when they are in the same country and their clocks showed the same time for the past year and will for the next two. Detroit and New York had different rules a century ago, so IANA keeps both, but they share an entry today. Zones that just changed their rules, like Edmonton, keep their own entry for a year, while browsers catch up.

alternativeName is the English name from CLDR without "Standard", "Daylight" or "Summer". When summer and winter names differ, like "Greenwich Mean Time" and "British Summer Time", it is CLDR's generic name, "United Kingdom Time". Several countries share names like "Eastern Time", so show countryName or mainCities next to it.

Abbreviations come from IANA. When IANA has none, like "+03", they come from abbreviations or read "GMT+3".