Time Zone Converter
Meeting links, flight itineraries and family calls fail the same way: somebody reads a clock time in the wrong zone. This converter takes one wall-clock time and two zones from a list of fourteen, then returns the target-zone time, says whether the calendar day rolls over, and reports the raw offset between the pair. The offsets are what airlines and APIs quote, so the arithmetic holds whatever the season.
Enter values
Results
- Time in the target zone
- 01:00
- Calendar day
- Same day
- Offset difference
- 13 h 30 min behind
How is the Time Zone Converter calculated?
Enter the hour and minute exactly as they read on a clock in the source zone, then pick both zones from the dropdowns — India Standard Time to Pacific, say. The calculator works in minutes from UTC: it shifts the entered time by the target offset minus the source offset, wraps the result into 00:00 to 23:59, and reports whether the wrapped clock landed on the same calendar day, the next one or the previous one. The final row states the offset gap in hours and minutes, ahead or behind.
Formula
Target time = source time + (target offset − source offset), modulo 24 hours. Offsets are standard minutes east of UTC: UTC 0, IST +330, PKT +300, GST +240, MSK +180, CET +60, BRT −180, EST −300, CST −360, MST −420, PST −480, JST +540, SGT +480, AEST +600. The calendar day shifts when the sum crosses midnight. Daylight saving is not applied.
Example
A 14:30 call from Delhi to Los Angeles: IST is UTC+5:30 and PST is UTC−8, a gap of 13 hours 30 minutes. Subtracting it from 14:30 lands on 01:00, still the same calendar day, because 14:30 IST is 09:00 UTC, which is 01:00 PST. Run 23:00 PST to IST instead: the 13 h 30 min forward shift overshoots midnight and arrives at 12:30 the next day.
Things to remember
Treat the zone labels as winter time: regions on daylight saving move their clocks forward in summer, and meetings slip until the changeover passes. Convert again close to any date scheduled months ahead. The calendar-day row deserves most attention — it separates calling at breakfast from waking somebody at night.
Frequently Asked Questions
What is the difference between GMT and UTC?
Practically none — UTC replaced GMT as the reference timescale and, unlike GMT, is maintained by atomic clocks rather than the Earth's rotation. Every offset on this page is stated against UTC, which is why the Eastern zone reads as five hours behind the reference.
Does this converter handle daylight saving time?
No, and that is deliberate: airline schedules, APIs and most international agreements quote standard offsets. When the destination is on summer time, expect its local clock one hour ahead of the figure shown here until the region's changeover dates pass.
Why does the converted time sometimes change day?
Because the two zones' offsets straddle midnight. Shifting 14:30 backwards by 13 h 30 min lands on 01:00 of the same date, while 23:00 shifted forward past midnight becomes 12:30 the next day — the calendar-day row names whichever happened.
Which time zones are included in the lists?
Fourteen covering the major scheduling routes: UTC itself, IST, PKT, GST, MSK, CET, EST, CST, MST, PST, BRT, JST, SGT and AEST. Each option states its standard offset in minutes, so half-hour zones such as India convert exactly instead of being rounded away.
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