Convert a local date and time from one selected IANA time zone into the matching local time in another. The converter preserves the instant, applies date-specific daylight-saving rules, shows both UTC offsets, and flags a previous- or next-date rollover. A clock time without its date or zone is incomplete.
The output gives two local representations of one instant. The source date and time are interpreted in the From zone; the target date, clock, abbreviation, and offset are the corresponding representation in the To zone. Publish all of those values together when scheduling.
How this is calculated
Interpret the entered YYYY-MM-DD and HH:mm as a wall-clock time in the From zone, resolve that moment with IANA rules, then format the same instant in the To zone. The result reports the target date, 24-hour local time and abbreviation, source and target UTC offsets, and whether the local dates differ. Check the selected date instead of applying a memorized fixed-hour difference.
Assumptions and limits
The entered date and time belong to the selected From zone, not the browser's local zone.
The current UI offers UTC, America/New_York, America/Los_Angeles, Europe/London, Europe/Paris, Asia/Kolkata, Asia/Tokyo, and Australia/Sydney; it is not a free-form all-zone search.
The browser-local duration tool has no IANA selector: calendar components and total seconds are distinct answers.
The Business Days calculator counts both range endpoints and can apply holidays; its reversed range is displayed as an unsigned count. Deadline addition advances after the start and is weekend-only, with no regional holiday selector yet.
Worked examples
India morning becomes New York evening on the prior date
Inputs: 2026-01-15 09:00; From Asia/Kolkata; To America/New_York
Result: Wed, Jan 14 · 22:30 EST; target 2026-01-14; UTC +05:30 to UTC -05:00
The same instant is 22:30 in New York, so the previous-day rollover is explicit.
Summer offsets are date-specific
Inputs: 2026-07-15 09:00; From Europe/London; To America/New_York
Result: Wed, Jul 15 · 04:00 EDT; target 2026-07-15; UTC +01:00 to UTC -04:00
Both zones use their July rules, producing a five-hour difference and no date rollover.
Late Pacific time becomes Tokyo's next date
Inputs: 2026-01-15 23:30; From America/Los_Angeles; To Asia/Tokyo
Result: Fri, Jan 16 · 16:30 GMT+9; target 2026-01-16; UTC -08:00 to UTC +09:00
The offset difference crosses midnight, which matters for international event dates.
Boundary cases
A spring-forward gap contains local clock labels that do not exist. The timezone runtime rejects that input rather than inventing an instant; choose a valid nearby time.
During the repeated fall-back hour, one local label can represent two instants. Confirm the displayed UTC offset before treating it as a unique meeting time.
A conversion can change the target calendar date while preserving the instant. Share the full date, time, named zone, and offset, not only the clock value.
Invalid dates, malformed HH:mm values, or unsupported zone selections produce no result. This tool does not calculate holiday-adjusted workdays.
Common mistakes
Using a remembered city difference without checking the event date and daylight-saving status.
Sharing a clock time without the target date after a midnight rollover.
Treating a repeated fall-back hour as unique without confirming its offset.
Assuming the converter accepts arbitrary city names or performs business-day and holiday calculations.