Free Time Zone Converter

Convert a date and time between any two time zones. Handles Daylight Saving Time automatically via the IANA time zone database. Quick reference: current time in New York, London, Tokyo, Sydney, and Los Angeles.

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What is this calculator for?

You're scheduling a meeting with a colleague in Tokyo and need to know what time 3 PM EST is in Japan. Or you're booking a flight to London and want to know whether you'll arrive on the same calendar day. Or you're trying to schedule a recurring call across multiple time zones. The timezone converter handles cross-timezone time conversion plus the daylight-saving-time complications that make this surprisingly hard.

US time zones (Eastern, Central, Mountain, Pacific) plus DST handling: in 2024-25, US DST runs from second Sunday in March to first Sunday in November. Arizona (most of state) and Hawaii don't observe DST. International time zones: UTC offset (e.g., +9 for Tokyo, -8 for Pacific Standard Time, 0 for London winter). Many countries also observe DST with different dates than the US — UK shifts a week before US, Australian states shift in their hemisphere's spring (October-April).

This tool converts times between zones, handles DST shifts correctly, and identifies date-line crossings (when a conversion changes the calendar date). For complex scheduling across many people: tools like worldtimebuddy.com or every.to overlay multiple zones visually.

How to use this calculator

Enter a date and time in your local zone (or any source zone). Pick target zone(s). The converter shows the equivalent times.

For recurring meeting scheduling: enter the meeting time once, the converter shows what that time means for each participant's zone. Useful for assessing whether "11 AM Eastern Tuesday" actually works for the Tokyo colleague (it'll be 1 AM Wednesday — terrible) or the London colleague (it'll be 4 PM, fine).

For travel planning: enter the departure date/time/zone and target arrival zone. The converter shows the arrival local time, including whether you'll cross the International Date Line or change calendar dates.

The DST complication: between November and March each year, the US shifts back to standard time, while many international zones maintain their offset. The "9 AM Pacific" you arranged in October becomes a different time globally when November arrives. The converter handles this automatically based on the specific date.

Understanding your results

The converter shows source time, target time(s), DST status in each zone for the date, and date-crossing notes when applicable.

Common time zone quick reference. Eastern Time (EST/EDT): UTC-5 (winter) / UTC-4 (summer). Central Time: UTC-6 / UTC-5. Mountain Time: UTC-7 / UTC-6 (Arizona stays UTC-7 year-round). Pacific Time: UTC-8 / UTC-7. UK (GMT/BST): UTC+0 / UTC+1. Central European (CET/CEST): UTC+1 / UTC+2. India (IST): UTC+5:30 (no DST). China (CST): UTC+8 (no DST). Japan (JST): UTC+9 (no DST). Singapore: UTC+8 (no DST). Sydney (AEST/AEDT): UTC+10 / UTC+11 (DST opposite to Northern Hemisphere, October-April).

The 24-hour difference common confusion. Tokyo is 14 hours ahead of Pacific Time (PST). New York is 14 hours behind Tokyo. So 3 PM PST Tuesday = 8 AM JST Wednesday. The "ahead" or "behind" language plus the date shift creates plenty of scheduling errors. For business across these zones: stick to mid-day-Eastern times that fall in someone's late-evening or early-morning, accept that someone will be inconvenienced.

The DST gotcha. Many international scheduling apps don't handle DST shifts correctly for past or future dates. Calendar events scheduled in advance may shift by an hour when DST starts or ends. Always double-check meetings near DST transition dates. The "always meet at 9 AM Tuesday" recurring event becomes "8 AM" or "10 AM" for the international participant when one zone shifts and the other doesn't.

The "American time" problem. Many countries say "9 AM" and mean 9 AM in their zone — clear. Americans often need to specify "Eastern" vs "Pacific" because of the 3-hour spread. International colleagues sometimes assume "ET" if no zone specified by American counterparts. Best practice: always include the zone (9 AM PT or 9 AM ET) in scheduling messages.

A worked example

Aisha works in San Francisco. Her team is distributed: Marcus in New York, Lin in Berlin, Daniel in Tokyo. She wants to schedule a 1-hour weekly team meeting that works for everyone.

Possible times converted:

9 AM PT Tuesday: 12 PM ET (NY: lunch hour). 6 PM CET (Berlin: end of work day). 1 AM JST Wednesday (Tokyo: nighttime, terrible). DOESN'T WORK.

7 AM PT Tuesday: 10 AM ET. 4 PM CET. 11 PM JST Wednesday (Tokyo: late evening, hard). DOESN'T WORK.

5 PM PT Monday: 8 PM ET (NY: evening, hard but possible). 2 AM CET Tuesday (Berlin: nighttime, no). 10 AM JST Tuesday (Tokyo: morning, good). DOESN'T WORK.

3 PM PT Monday: 6 PM ET. 12 AM CET Tuesday (Berlin: midnight, no). 8 AM JST Tuesday. DOESN'T WORK.

Reality: no single hour works for all four zones during reasonable workdays. Solution: alternating times. Two weeks: meeting at 5 PM PT (10 AM JST Tuesday) — Aisha and Daniel inconvenient for others. Two weeks: meeting at 7 AM PT (4 PM CET) — Lin convenient, Marcus and Aisha OK, Daniel late evening. Daniel rotates between attending sometimes vs reviewing recording.

The lesson: 4-zone meetings across the Pacific and Europe and US East rarely work in single weekly meetings; rotating times or async communication (Slack, recorded video, written updates) is more sustainable. For truly globally-distributed teams: avoid synchronous meetings except occasionally; embrace async workflows.

Related resources

For broader date math, see Date Calculator. For age calculations across timezones, the Age Calculator. For pregnancy and event-related date conversions, the Due Date Calculator. timeanddate.com is the most comprehensive timezone and international time reference; WorldTimeBuddy is the standard tool for visual cross-timezone scheduling.

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Frequently asked questions

Does this tool handle Daylight Saving Time?

Yes. The conversion uses the IANA Time Zone Database (tzdata) via your browser's Intl.DateTimeFormat API, which knows the DST rules for every region. When you pick a date and time, the converter checks whether DST is in effect at that specific moment in each zone and applies the correct offset. Note that some countries (Russia, Iceland, most of Asia and Africa, Arizona, Hawaii) do not observe DST.

What is UTC?

UTC (Coordinated Universal Time) is the world's primary time standard — the reference from which all civil time zones are offset. It does not observe Daylight Saving Time. Aviation, computing, scientific timestamps, and international protocols (HTTP, SMTP, RSS) all standardize on UTC. UTC is identical to GMT for most practical purposes, though GMT technically refers to mean solar time at the Royal Observatory in Greenwich, while UTC is defined by atomic clocks.

How many time zones are there?

Civil time has 38 distinct UTC offsets currently in use, ranging from UTC−12:00 (Baker Island) to UTC+14:00 (Kiribati/Line Islands). Some zones use 15- or 30-minute offsets — India is UTC+5:30, Nepal is UTC+5:45, parts of Australia are UTC+8:45 (Eucla) and UTC+9:30 (Adelaide). The IANA database catalogs ~600 named zones, but many share the same offset and DST rules.

How many time zones are there?

Officially: 24 standard zones plus several half-hour offsets and a few quarter-hour offsets. Practically: about 40 unique time offsets are in use worldwide. Examples of unusual offsets: India (UTC+5:30 — 30 min off), Nepal (UTC+5:45 — 15 min off), Iran (UTC+3:30), Australian Central (UTC+9:30), Chatham Islands NZ (UTC+12:45 — quarter-hour offset). Plus DST creates additional offsets in some zones. The full list of zones is maintained in the IANA Time Zone Database (tzdata), used by all major operating systems and programming languages.

Why doesn't all of the US observe daylight saving time?

Federal law (1966 Uniform Time Act and amendments) allows states to opt out of DST observance. Arizona opted out in 1968; most of the state observes Mountain Standard Time year-round. The exception: the Navajo Nation (within Arizona) does observe DST. Hawaii also doesn't observe DST. Florida, California, and several other states have passed laws to stay on DST permanently year-round, but those require federal approval (not yet granted). Multiple proposals to abolish DST have been introduced in Congress over the years; none have passed. As of 2024-25, the US still observes DST in 48 states for 8 months per year.

What's the difference between EST and EDT?

EST (Eastern Standard Time) is UTC-5, used in winter (early November to early March). EDT (Eastern Daylight Time) is UTC-4, used in summer (early March to early November). 'Eastern Time' (ET) is the colloquial term that includes both. When scheduling: 'ET' is acceptable for most purposes; 'EST' specifically means winter time, 'EDT' specifically means summer time. The distinction matters across the DST transition dates — a meeting scheduled at 'EST' in mid-March is technically EDT by then, causing confusion. Best practice: use 'ET' or specify exact UTC offset.

How do I schedule across many time zones?

Use specialized tools. WorldTimeBuddy.com: overlays multiple zones for visual scheduling. When2Meet: lets multiple people indicate availability in their own zones; finds intersection. Google Calendar 'World Clock': displays multiple zones in calendar view. Microsoft Outlook similarly supports multiple zones. For ad-hoc one-time meetings: a calendar invite with the time specified in UTC, plus auto-conversion in everyone's calendar handles it. For recurring meetings across many zones: rotate times to share the inconvenience equally; consider whether async communication can replace synchronous meeting.

When does daylight saving time start and end?

United States: starts second Sunday in March (clocks 'spring forward' from 2 AM to 3 AM). Ends first Sunday in November (clocks 'fall back' from 2 AM to 1 AM). 2025 dates: starts March 9, ends November 2. 2026: starts March 8, ends November 1. Europe (most countries): last Sunday in March to last Sunday in October — usually one week before US in spring, one week before US in fall. Australia (DST observing states): first Sunday in October to first Sunday in April — opposite of Northern Hemisphere. Many countries don't observe DST (China, Japan, India, most of Africa). When scheduling internationally near DST dates: check both zones' DST schedules specifically.

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