Timezone Conversion Calculator
Convert a date and time to up to 5 timezones at once.
How timezone conversion works
Your source date and time, together with its IANA timezone, are resolved to a precise moment in UTC — the common reference point every other timezone can be measured from. That UTC moment is then converted into each target timezone using the IANA database's current rules for that specific date, which is why the same conversion can produce a different UTC offset depending on whether daylight saving is in effect on either side.
The day-difference column matters more than it might seem — a conversion near midnight can land on the previous or next calendar day in the target timezone, which is a common source of scheduling mistakes if overlooked. For finding a good overlapping meeting time across several timezones directly, rather than converting a single point in time, see the Meeting Planner & World Clock, and for converting a timestamp rather than a human-readable date, see the Unix Timestamp Converter.
Frequently asked questions
- How do I search for a city instead of typing the IANA name?
- Start typing a city or country and the field will suggest matching IANA timezone names (e.g. typing "york" suggests "America/New_York"). You can also type the IANA name directly if you know it.
- What does "day difference" mean?
- Whether the converted time falls on the same calendar day as your source time, or the day before/after — useful for scheduling across timezones near midnight.
- How is DST handled?
- Each conversion is resolved against the real IANA timezone database for the exact date and time you enter, so daylight saving transitions are applied automatically and correctly for that specific date.
- What is a time zone offset?
- A timezone offset is how many hours (and sometimes minutes) a local timezone differs from UTC — for example, UTC-5 for US Eastern Standard Time. Offsets can change through the year for locations that observe daylight saving time.
- What is UTC and how does it relate to GMT?
- UTC (Coordinated Universal Time) is the global time standard used as the reference point for every other timezone. GMT (Greenwich Mean Time) is a specific timezone that shares UTC's offset for most of the year — the two are commonly used interchangeably, though UTC is the technically precise standard.
- What is the IANA timezone database?
- The IANA (Internet Assigned Numbers Authority) timezone database is the authoritative, regularly updated dataset of every timezone in the world, including their historical and current UTC offsets and daylight saving rules. It's the standard reference nearly all software uses for accurate timezone conversion, identified by names like "America/New_York" or "Asia/Tokyo".
- Why do some countries have half-hour or 15-minute UTC offsets?
- Not every timezone uses a whole-hour offset from UTC — India (UTC+5:30), Nepal (UTC+5:45), and parts of Australia (UTC+9:30) are notable examples. These offsets typically reflect a country choosing a time standard based on its geographic centre or historical precedent rather than aligning to the nearest whole hour.