How it works
Choose a home city and the clock time of your meeting there, then choose one or two target cities to convert that time to. This calculator looks up each city’s fixed standard-time UTC offset, works out the difference between the home city and each target city, and shifts the meeting time by that difference to produce a converted clock time and a same-day, previous-day, or next-day label.
Important limitation: this calculator uses each city’s fixed standard-time UTC offset from the IANA Time Zone Database. It does not compute live daylight saving time for any city. Because the United States and the European Union/United Kingdom begin and end daylight saving time on different calendar dates, roughly one to two weeks apart each spring and fall, a converted time can be off by exactly one hour during those transition windows, when one city has shifted to daylight saving and the other has not yet. Outside those transition weeks the fixed offsets used here match real clock time for every supported city.
The formula
homeMin = meetingHour x 60 + meetingMinute diffMin = targetOffsetMin - homeOffsetMin totalMin = homeMin + diffMin targetMin = ((totalMin mod 1440) + 1440) mod 1440 (safe modulo, wraps to 0-1439) dayShift = floor(totalMin / 1440) (-1 previous day, 0 same day, +1 next day)
Worked example
Meeting at 9:00 AM in New York (UTC-5), converting to London (UTC+0):
- Home time in minutes: 9 x 60 + 0 = 540 minutes
- Offset difference: 0 - (-300) = +300 minutes
- Total: 540 + 300 = 840 minutes
- Wrapped clock time: 840 minutes = 14:00, formatted as 2:00 PM
- Day shift: floor(840 / 1440) = 0, so the result is the same day
Frequently asked questions (FAQ)
Does this calculator account for daylight saving time?
No. This calculator uses each city's fixed standard-time UTC offset from the IANA Time Zone Database, not a live daylight-saving-aware conversion. Because the US and the EU/UK switch to and from daylight saving time on different calendar dates, a result can be off by exactly one hour during those transition weeks. Double-check the offset by hand during early March, late October, and early November.
Why might my meeting show a different time than my phone's clock or calendar app?
Your phone and calendar app track live daylight saving rules for every city automatically, while this calculator uses fixed standard-time offsets. Outside the DST transition weeks the two will typically agree, since most of the world's clocks match the standard offset most of the year. During transition weeks, trust your calendar app over this calculator for the exact hour.
What does "previous day" or "next day" mean in the result?
A meeting time near midnight in one city can land on a different calendar date in another. If the converted time crosses backward over midnight it is labeled previous day, and if it crosses forward over midnight it is labeled next day. Same day means the converted time falls on the same calendar date as the home city's meeting time.
Why is Mumbai/Delhi's offset a half hour instead of a whole hour?
India uses a single time zone, Indian Standard Time, set at UTC+5:30, a half-hour offset rather than a whole hour. This calculator stores every offset in minutes internally, so the half-hour difference is handled exactly and never rounded away when converting to or from Mumbai/Delhi.
Can I convert to more than two cities at once?
This calculator converts to two target cities at a time to keep the result easy to read. Set Target city 2 to None if you only need one conversion, or run the calculator twice with different target cities to check a third or fourth location.
What should I do during the DST transition weeks in March and November?
During the one to two weeks when US clocks and EU/UK clocks have not both made their daylight saving switch, manually add or subtract one hour from this calculator's result for any city pair spanning those regions. Outside that narrow window, the fixed standard-time offsets used here match the real clock time.
Sources
- IANA Time Zone Database, the canonical source for standard UTC offsets used by every supported city in this calculator.