This time zone converter answers the meeting-scheduler’s question: when it’s a given time there, what time is it here? Pick a date and time, a source zone and a destination zone — daylight saving is handled by the real zone rules, not a fixed offset table.
Why Fixed Offsets Betray You
“EST is UTC−5” is only true in winter; by July, New York is UTC−4 — and the US and Europe change clocks on different weekends, creating two annual windows where the NY–London gap is 4 or 6 hours instead of 5. This converter computes offsets from the IANA zone rules for your exact date (the same database your phone uses), which is the only honest way to schedule across zones. Durations and date arithmetic live in our Date Calculator and Time Calculator. Part of our Other Calculators collection.
Worked Example (Verified)
- Jan 15, 2026, 12:00 noon in New York → London: New York is on EST (UTC−5), London on GMT (UTC+0) → 5:00 PM the same day — the widget’s default, a 5-hour gap
- The same call in July: EDT (UTC−4) vs BST (UTC+1) → still 5 hours, by coincidence of both regions shifting
- The trap weeks: late October, when Europe has fallen back but the US hasn’t, the gap is 4 hours; in mid-March the reverse gap is 6 — recurring meetings drift an hour in one region’s calendar, a classic scheduling bug this converter sidesteps
- Date-line reality: 9:00 AM Monday in Los Angeles is 5:00 AM Tuesday in Auckland (in January) — the converter shows the weekday so the day shift is never a surprise
Practical Conventions
- Always include the zone name (not just “3 PM”) in cross-zone invitations — and prefer the recipient’s zone in the message.
- UTC is the lingua franca for logs, aviation and servers precisely because it never observes DST.
- Half-hour zones are real (India +5:30, Nepal +5:45): “hour difference” can end in .5 or .75 — this converter’s differences can too.
- For recurring meetings, anchor to one zone and let the others float with their DST rules — and re-verify after each transition month.
Related Tools
- Date Calculator — days between, add and subtract
- Time Calculator — durations and decimal hours
- Other Calculators — the full collection
Frequently Asked Questions
How do I convert time between time zones?
Take the wall time in the source zone, find its UTC instant using that zone’s offset on that date, then render it in the destination zone’s offset on the same date. Noon in New York on Jan 15 is 17:00 UTC, shown in London as 5:00 PM. This calculator performs both offset lookups from live zone rules.
Why does the time difference change during the year?
Daylight saving: regions advance clocks in (their) spring and retreat in autumn, on dates that differ by country — and the southern hemisphere runs opposite seasons entirely. Any fixed hour-difference you memorize has expiry dates.
What is UTC and why do systems use it?
Coordinated Universal Time: the zero-offset reference, immune to DST and geography. Timestamps stored in UTC convert unambiguously to any local zone; timestamps stored in local time without the zone are how databases lose hours.
How many time zones are there?
About 38 distinct current UTC offsets (including :30 and :45 minute zones), spread across ~400 named IANA zones that capture historical and political variations — which is why converters select zones by city, not by offset.
Does this handle daylight saving correctly?
Yes — offsets are resolved per date through the browser’s IANA zone database (the same rules operating systems use), including transition-week edge cases. For the two “gap/overlap” hours on transition days themselves, the result follows the standard post-transition interpretation.
Is this time zone converter free?
Yes — free, instant, no sign-up.