Time Zone Converter
How it works
Every zone's offset from UTC is looked up fresh for the exact date you entered, then used to translate your wall-clock time into the target zone's wall-clock time at that same instant. Looking it up per-date, rather than assuming a fixed offset per zone, is what keeps a conversion correct whether or not either side happens to be observing daylight saving time on that day.
Frequently asked questions
Why does the hour difference between two zones change across the year?
Daylight saving time. A place that observes it shifts its clocks forward or back by an hour on its own schedule, so a pair of zones that sit 5 hours apart in January can sit 4 hours apart in July — or the other way around, if only one of the two observes DST at all. This converter recomputes the real offset for the exact date you enter rather than assuming a fixed gap.
Where do the time zone rules come from?
Your browser's own time zone database, via the same Intl API every other date feature on the web uses. Nothing is fetched from a server, and there is no bundled table to fall out of date — if your browser has the current rule for a zone, so does this page.
What's the difference between an offset and a named zone?
"UTC-5" is just a number, and by itself it does not say whether daylight saving applies. "America/New_York" is a named zone — a place with its own rules for when the offset changes through the year. Converting by name, not by a fixed offset, is what keeps the result correct on both sides of a DST transition.