How to use the time zone converter
- When the page opens, Live (now) is ticked and the table is a world clock: every city on your list shows its current local time, updated each second, with the date and its offset from UTC.
- To convert a specific moment, set the Date and time and choose the zone it belongs to under In this time zone. Live mode switches off, the source row is highlighted, and every other row shows the matching local time, marked “(+1 day)” or “(−1 day)” when the date is different.
- Add any city or zone with the menu below the table, and remove rows with ✕. Reset list restores the default: your own zone plus UTC, Los Angeles, New York, London, Paris, Dubai, Kolkata, Shanghai, Tokyo and Sydney.
Your own zone is detected from your device settings, and the menu lists every zone your browser knows, sorted by city with its current offset. The list of cities is saved in this browser.
Examples
- Seoul to California. 10:00 on Tuesday 10 November 2026 in Seoul is 17:00 on Monday 9 November in Los Angeles (−1 day) and 20:00 on Monday in New York. In July the same Seoul time is 18:00 in Los Angeles, because California is then on daylight saving time.
- The spring gap. The US moves its clocks forward on 8 March 2026, the UK not until 29 March. A 9:00 meeting in New York on 10 March is 13:00 in London instead of the usual 14:00 – for three weeks the cities are only four hours apart.
- Half-hour offsets. 15:00 in London in January is 20:30 in Kolkata (UTC+5:30) and 20:45 in Kathmandu (UTC+5:45).
- Opposite seasons. 9:00 in Sydney is 22:00 the previous evening in London in January (11 hours apart) but midnight in July (9 hours apart), and for a few weeks in between the gap is 10 hours, because the two cities change their clocks in opposite directions on different dates.
UTC, offsets and the IANA time zone database
Coordinated Universal Time (UTC) is the reference all other zones are measured from. An offset says how far local clocks are ahead of or behind it: Tokyo and Seoul are UTC+9, New York UTC−5 in winter and UTC−4 in summer. Offsets aren't always whole hours – India uses +5:30, Nepal +5:45, Newfoundland −3:30 – and they run from UTC−12 to UTC+14.
Because offsets change with daylight saving time and occasionally by law, software doesn't store “New York = −5”. It uses the IANA time zone database, which records the rules and their history under identifiers such as America/New_York or Asia/Seoul, shown in small type under each city in the table. Each identifier is named after one representative city, and places that have kept the same clocks since 1970 share it. The converter relies on the copy of this database built into your browser, so clock changes are applied correctly for any date as long as the browser is up to date.
Daylight saving time
The US and Canada move their clocks forward on the second Sunday in March and back on the first Sunday in November. The UK and the EU change on the last Sunday of March and of October, at 01:00 UTC. Seasons are reversed in the southern hemisphere: Sydney is on UTC+11 from early October to early April and UTC+10 for the rest of the year. Japan, South Korea, China and India don't use daylight saving time at all, and some regions opt out inside a country – most of Arizona stays on UTC−7 all year.
Planning across time zones
- Enter the time in the organiser's zone and check that every row falls within working hours.
- For a recurring meeting, also check a date in March–April and in October–November, when gaps between regions shift by an hour.
- In invitations, name a city or give the UTC time (“15:00 UTC”) rather than an abbreviation. CST can mean US Central, China or Cuba Standard Time, and IST is used in India, Ireland and Israel.
- To read times in server logs, use the Unix Timestamp Converter; to count the days until an event, use the Date Calculator.
Common abbreviations
| UTC / GMT | UTC±0. London is on GMT in winter and BST (UTC+1) in summer. |
|---|---|
| ET (EST / EDT) | New York: UTC−5, or UTC−4 in summer |
| PT (PST / PDT) | Los Angeles: UTC−8, or UTC−7 in summer |
| CET / CEST | Paris, Berlin: UTC+1, or UTC+2 in summer |
| IST (India) | UTC+5:30 all year |
| CST (China) | UTC+8 all year |
| JST / KST | Japan, Korea: UTC+9 all year |
FAQ
Is daylight saving time handled automatically?
Yes. Offsets are worked out for the exact date you enter, so a meeting in July and one in December can show different gaps between the same two cities.
What about times skipped or repeated by a clock change?
When clocks spring forward, an hour of local time never happens (in New York on 8 March 2026, 2:00–2:59 a.m. is skipped). If you enter such a time, the highlighted row shows the nearest real time, an hour away. When clocks fall back, one hour happens twice; the converter picks one of them, and the offset column shows which.
My city isn't listed. Which should I choose?
Pick the city that names your zone: San Francisco and Seattle use Los Angeles, Boston uses New York, Osaka uses Tokyo, and all of mainland China uses Shanghai. Some browsers list a few places under older spellings, such as Calcutta for Kolkata or Kiev for Kyiv – they are the same zone.