Time & Date

Timezone Converter

Convert wall-clock dates and times between global IANA time zones with daylight saving gap and overlap detection.

How It Works & Methodology

Converting times across international timezones involves mapping local wall-clock times to UTC instants and then to target timezones. Transitions into and out of Daylight Saving Time (DST) create two critical edge cases: spring-forward gap (a local time that does not exist) and fall-back overlap (a local time that occurs twice).

1. Source Wall Time -> UTC Instant via IANA Olson Database. 2. Nonexistent time (e.g. 02:30 during spring-forward) is rejected with explicit explanation. 3. Repeated time (e.g. 01:30 during fall-back) is flagged as ambiguous and resolved via explicit earlier/later selection.
Key Assumptions & Scope:
  • Calculations strictly rely on ECMAScript standard IANA Intl time zone rules.
  • Does not guess or silently skip invalid spring-forward gap hours.
  • Offsets are computed in minutes relative to UTC.

Frequently Asked Questions

What happens during Daylight Saving Time (DST) spring-forward?

When clocks jump forward from 02:00 to 03:00, wall clock times like 02:30 do not exist in that time zone. This converter flags and rejects nonexistent gap times.

What is an ambiguous fall-back time?

When clocks turn back one hour in autumn (e.g. 02:00 back to 01:00), times between 01:00 and 02:00 occur twice. The disambiguation selector lets you choose whether you mean the earlier (daylight) or later (standard) occurrence.

Does this handle fractional time zone offsets like India or Nepal?

Yes. Regions like Asia/Kolkata (UTC+5:30) or Asia/Kathmandu (UTC+5:45) are converted with exact minute precision.