How does the timezone converter work?

Select a source timezone, enter the date and time, then pick a target timezone to see the converted time instantly.

Does it handle daylight saving time?

Yes, the converter uses IANA timezone data via date-fns-tz which correctly handles DST transitions.

Timezone Converter — World Clock & Time Difference

Timezone Converter

Convert date and time between different timezones.

Select date, time, and timezones to convert.

What This Converter Does

Scheduling anything across regions means translating a date and time from one place's local clock into another's, which gets genuinely tricky once daylight saving time enters the picture — the offset between two cities isn't always the same number of hours year-round. This tool takes a date and time in one timezone and tells you the corresponding wall-clock time in another, offset included.

How to Use It

Enter a Date & Time in YYYY-MM-DD HH:MM format — it's pre-filled with the current date and time so you can see a live example right away. Pick a From Timezone and To Timezone from the two dropdowns, each offering seven popular zones: New York, Los Angeles, London, Paris, Tokyo, Sydney, and Kolkata. The result shows the converted date and time in the target zone, along with its UTC offset at that exact moment — which, for any zone that observes daylight saving, can differ depending on the time of year.

The Formula

Rather than applying a fixed offset, the converter resolves your entered date and time as real wall-clock time in the source timezone, converts that to the single underlying UTC instant it actually represents, then re-expresses that same instant as wall-clock time in the target timezone. This is what makes DST handling correct: the tool relies on IANA timezone data (via the date-fns-tz library) that encodes exactly when each zone's clocks shift and by how much, rather than assuming a timezone's offset from UTC never changes.

A Worked Example

US clocks "spring forward" for daylight saving on the second Sunday of March, and 2024's transition happened at 2:00 AM Eastern Time on March 10 — clocks jumped straight from 1:59 AM to 3:00 AM, skipping the entire 2 AM hour. You can see that jump directly: convert 2024-03-10 06:59 from London to New York and you get 2024-03-10 01:59 (America/New_York - UTC-05:00) — still Eastern Standard Time, one minute before the transition. (London and the pre-transition UTC instant coincide exactly here, since the UK's own DST doesn't start until the last Sunday of March, later in the same month.) Convert just one minute later, 2024-03-10 07:00 London time, and the result jumps to 2024-03-10 03:00 (America/New_York - UTC-04:00) — now Eastern Daylight Time, a full hour ahead of the previous result despite only one minute passing in London.

How to Convert Timezones Manually

Look up each zone's current UTC offset — not its "usual" offset, but the one that actually applies on your specific date, since DST-observing zones use a different offset for roughly half the year. Subtract the source zone's offset from the target zone's offset to get the hour (and sometimes half-hour) difference between them, then add that difference to your source time. London to New York outside of any transition window is a steady 5-hour difference (UTC+0 versus UTC−5, or UTC+1 versus UTC−4 when both observe their own DST). The genuinely error-prone part is exactly the case above: near a transition date, the difference itself changes mid-calculation, so doing this by hand around early-to-mid March or late October for US/UK conversions is worth double-checking against an actual DST calendar rather than assuming last month's offset still applies.

FAQ

How does the timezone converter work?: Select a source timezone, enter the date and time, then pick a target timezone to see the converted time instantly.
Does it handle daylight saving time?: Yes, the converter uses IANA timezone data via date-fns-tz which correctly handles DST transitions.