Time Zone Converter: World Time Between Cities

Guide

How time zones work

Time zones are offsets from Coordinated Universal Time (UTC). New York is UTC−5 in winter and UTC−4 in summer, London is UTC+0 or UTC+1, India is UTC+5:30 all year, and Tokyo is UTC+9. Some zones use half-hour or even 45-minute offsets, such as Nepal at UTC+5:45. This converter uses your browser's built-in IANA time zone database, so daylight saving rules and historical changes are applied correctly for the date you choose.

Worked example

A call at 9:00 in New York on 15 January is 14:00 in London, 19:30 in New Delhi and 23:00 in Tokyo the same day. In July, when New York and London are both on daylight saving time, 9:00 in New York is still 14:00 in London but 18:30 in New Delhi, because India does not change its clocks.

Daylight saving time

Many countries in North America and Europe move their clocks forward one hour in spring and back in autumn, but they change on different dates. For a few weeks each year the gap between, say, New York and London is four hours instead of five. Most of Asia, Africa and South America do not use daylight saving. Because the converter works from the actual date, it handles these transition weeks automatically.

Scheduling across time zones

For international meetings, look for overlapping working hours and avoid very early or late slots for any participant. Writing the time with its zone, for example 15:00 UTC, prevents confusion. When booking flights remember that arrival times are always local to the destination, so a flight can appear to land before it took off.

Private and offline-friendly

All conversions run on your device using standard browser features; no external service is called, so the tool is fast and works worldwide.

Key terms

UTC

Coordinated Universal Time, the global reference clock from which all zones are measured.

Offset

The number of hours and minutes a zone is ahead of or behind UTC, such as UTC+5:30.

Daylight saving time

A seasonal clock change, usually one hour forward in spring and back in autumn.

IANA time zone

A standard name such as Europe/London or Asia/Kolkata that includes all historical rule changes.

GMT

Greenwich Mean Time, often used interchangeably with UTC in everyday speech.

International Date Line

The line in the Pacific where the calendar date changes by one day.

Local time

The clock time in a particular place, including any daylight saving adjustment.