How this tool works
Include Z for UTC or the numeric offset shown on an invitation or calendar export. The source and target displays use the named zones to find their local time and date at that instant.
Parse the explicit UTC offset to obtain the instant. Format the same instant separately in each IANA zone.A worked example
12:00 UTC on 9 November 2026 is 17:30 in Asia/Kolkata and 12:00 in Europe/London.
Good to know
The browser supplies the time-zone rules. The entered offset defines the instant, including when the selected source display zone has a different offset.
How the inputs affect the result
Include the date when sharing a cross-zone time. A target zone may already be on the next calendar day, and the offset can change with the season.
The same UTC hour displays one hour later in London during summer time.
Where the calculation applies
The browser supplies the time-zone rules. The entered offset defines the instant, including when the selected source display zone has a different offset.
For a related calculation, see the Date and time duration calculator.
A few questions, answered
Why do I have to provide an offset?
A clock time can occur twice when clocks move back, or be skipped when they move forward. An explicit offset picks a unique instant.
What does the “London during summer time” setting illustrate?
The same UTC hour displays one hour later in London during summer time.