Why the date matters, not just the time
Time zone offsets change through the year. New York is UTC−5 in January but UTC−4 in July; London is UTC+0 in winter and UTC+1 in summer. Worse, the switch dates differ — the US changes in March and November, Europe in late March and late October — so the New York–London gap is usually 5 hours but drops to 4 for a couple of weeks each year. That's why this converter asks for a full date and computes the offset for that exact day.
Zones that skip DST or use odd offsets
Plenty of places never change their clocks: Arizona (mostly), Hawaii, Japan, China, India, and Singapore among them. India runs on a half-hour offset (UTC+5:30), and China spans five geographic zones but uses a single national time. Meanwhile southern-hemisphere zones like Sydney observe DST in the opposite season — the Sydney–New York gap swings between 14 and 16 hours across the year. Rules also change by government decree, which is why date-aware databases beat memorized offsets.
Scheduling across zones without mistakes
State the city alongside the time ('3 pm New York time'), not an abbreviation — 'CST' alone can mean Central US, China, or Cuba time. For recurring international meetings, anchor the time in one named city and let everyone else's local time float with DST changes; that's what calendar apps do internally, and it's the behavior this converter mirrors.
How to use this converter
Pick the source city and time, choose a target city, and set the date — the date is essential because the offset depends on whether daylight saving is active that day. Below the direct conversion, a table shows the same instant in all 20 supported cities, which is the fastest way to find a meeting slot that works across several regions at once.
A worked example
Schedule a call for 9:00 am in New York on July 15. Because both New York (UTC−4 in summer) and London (UTC+1 in summer) are on daylight time, the gap is 5 hours, so it's 2:00 pm in London and 6:30 pm in Mumbai (UTC+5:30, no DST). Move the same 9:00 am call to January and New York shifts to UTC−5 while London returns to UTC+0 — still 5 hours — but the Sydney gap changes, because Sydney runs DST in the opposite season.