UTC (Coordinated Universal Time) is the primary global time standard. It does not change for daylight saving time. All time zones are expressed as UTC offsets, for example UTC+1 or UTC-5.

What is daylight saving time?

Daylight saving time (DST) advances clocks by one hour during warmer months. Not all countries observe DST and the dates differ by region. Our converter accounts for DST automatically.

What is the difference between GMT and UTC?

GMT (Greenwich Mean Time) and UTC share the same numeric value. GMT is a time zone used in the UK in winter; UTC is a universal time standard. For practical conversion purposes they are identical.

How do I schedule a meeting across time zones?

Find a window that falls within business hours (9am-5pm) for all participants. Enter your local time and check the displayed time in each participant's zone to find mutual overlap.

What are the most common time zones?

Frequently used zones include UTC, GMT (UK winter), CET/CEST (Central Europe), EST/EDT and PST/PDT (US East and West), IST (India, UTC+5:30), JST (Japan, UTC+9), and AEST/AEDT (Australia Eastern).

Time Zone Converter — Convert Times Between Cities

Date & Time

From

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Current time around the world

About the Time Zone Converter

Convert any date and time between any two of the world's time zones instantly. The converter uses the full IANA time zone database, so every country, region, and territory is supported — and daylight saving time transitions are handled automatically based on the selected date.

How it works

Select your source date and time, choose the time zone it's in, then pick the target time zone. The converted result appears immediately. All calculations happen in your browser with no server round-trips needed.

Daylight saving time

DST rules vary by country and change year to year. The converter automatically applies the correct offset for the specific date you enter — so a summer conversion from London to New York will correctly use BST (UTC+1) and EDT (UTC−4), while a winter conversion will use GMT and EST.

UTC and time zone offsets

UTC — the global baseline; all other zones are expressed as offsets from it
UTC+1 (CET) — Central European Time (standard)
UTC−5 (EST) — Eastern Standard Time (US & Canada)
UTC+8 (CST) — China Standard Time / Singapore
UTC+9 (JST) — Japan Standard Time

Common uses

Scheduling international calls and meetings, booking flights across time zones, coordinating remote teams, and verifying the local time of a past or future event in another country.

Daylight Saving Time and scheduling

Daylight Saving Time (DST) is one of the most common sources of scheduling bugs. Clocks in the UK move forward 1 hour in March and back in October. The US changes on different dates to the UK, creating a 3-week period each spring and autumn when the transatlantic time difference is 1 hour different from usual. Always store times in UTC in databases and convert to local time for display.

UTC vs local time — always store in UTC; convert to local time only for display
IANA timezone database — the authoritative source of timezone rules; used by all major programming languages
DST transitions — clocks change at different times in different countries; the US-EU gap varies by 3 weeks each spring and autumn
ISO 8601 with offset — 2025-06-01T14:30:00+01:00 is unambiguous; naked local times are ambiguous during DST transitions

Time zones in software development

Timezone handling is one of the most error-prone aspects of software development. Rules change (countries add, remove, or modify DST), historical data may be inaccurate, and the same city can be in different zones depending on the date. The IANA timezone database (also called the Olson database) is the authoritative source, updated several times per year.

UTC everywhere — store all timestamps as UTC; convert to local time only at the display layer
IANA database — always use IANA zone names (Europe/London) not fixed offsets (+00:00); offsets change with DST
Moment.js vs date-fns vs Temporal — Moment is deprecated; date-fns or Luxon are current recommendations; the JavaScript Temporal API is the future standard
Database storage — PostgreSQL TIMESTAMPTZ stores UTC correctly; MySQL TIMESTAMP has a 2038 limit

Frequently Asked Questions

How do I convert time zones?

Select your date and time, choose your source time zone, then pick the target time zone. The converted time appears instantly.

What time zones are supported?

We support all major IANA time zones covering every country and region worldwide.

How does daylight saving time affect conversions?

Our converter automatically accounts for daylight saving time (DST) based on the selected date, so you always get the correct local time.

What is UTC?

UTC (Coordinated Universal Time) is the global time standard. All other time zones are expressed as offsets from UTC, e.g. UTC+1 for Central European Time.

How do I schedule a meeting across multiple time zones?

Use a tool like World Time Buddy or Every Time Zone to find an overlap during business hours. The classic overlap between London (GMT+1 BST) and New York (EDT GMT-4) is 2pm-6pm London / 9am-1pm New York. For teams across Asia and Europe, finding any overlap during working hours is often impossible and asynchronous communication is more practical.