Frequently asked questions
Does TheTimeCalc account for Daylight Saving Time?
Yes. TheTimeCalc uses the IANA time zone database — the same data most operating systems and browsers rely on — so daylight saving transitions are applied automatically and correctly for every date you check, not just today.
Why does the converted time sometimes show a different date?
Time zones don't just shift the hour, they can shift the calendar day too. If it's 11 PM in Tokyo, it can still be earlier the same day — or even the previous day — somewhere far to the west. When a conversion crosses midnight, TheTimeCalc labels it clearly as "previous day" or "next day" so you don't have to work it out yourself.
What's the difference between GMT and UTC?
For everyday purposes they're interchangeable — both describe the same reference point at 0 hours offset. UTC (Coordinated Universal Time) is the precise modern standard used for time zone calculations; GMT (Greenwich Mean Time) is the older, historical name for essentially the same thing, and is also the actual local time zone for the UK in winter.
Why is India's time zone offset 5 hours and 30 minutes?
Not every country aligns to a whole-hour offset from UTC. India Standard Time is UTC+5:30, chosen so a single time zone could reasonably serve the whole country despite its east-west width. Other examples include Nepal (UTC+5:45) and parts of Australia (UTC+9:30). TheTimeCalc handles these half-hour and 45-minute offsets the same way it handles whole-hour ones.
How accurate is the time zone data used?
TheTimeCalc relies on the IANA time zone database, the industry-standard source maintained specifically to track time zone rule changes, including daylight saving adjustments that governments announce or alter from year to year.
Can I use TheTimeCalc to schedule international meetings?
Yes — that's exactly what the Meeting Planner tool is for. Set your own location and time, add up to two more cities, and see the equivalent local time in each instantly, without doing the math yourself.
Does TheTimeCalc work for time zones that don't observe Daylight Saving Time?
Yes. Most of Asia, for example, doesn't observe DST at all, while the US and Europe do (on different schedules from each other). Because the underlying data is date-aware, TheTimeCalc applies the correct rule for each specific zone and date automatically.
Is TheTimeCalc free to use?
Yes, entirely free, with no account or sign-up required.