Workings

Time Zone Converter

Choose a date, a time and the zone it is in, then the zone you want — the result includes the date change if there is one.

Time Zone Converter

Your result will appear hereFill in the fields and press “Calculate”.

Formula

  • UTC = local time − source offset
  • target time = UTC + target offset
  • Offsets depend on the date, because of daylight saving.

Convert to universal time first, then to the destination zone.

Worked example

9:30 in Kolkata → New York

Date
2026-01-15
Time (24-hour)
09:30
From
India — Kolkata / Mumbai / Delhi
To
US Eastern — New York

Time in New York

Wed, 14 Jan 2026, 23:00 (UTC-05:00)

Date there: Wednesday, 14 January 2026

Difference: 10.5 hours behind Kolkata

UTC time: Thu, 15 Jan 2026, 04:00 UTC

How it works

9:30 in India (UTC+05:30) on 15 January is 04:00 UTC, which is 23:00 on 14 January in New York (UTC−05:00) — so the date changes as well as the time. The tool always shows the date at the destination.

Daylight saving makes some local times impossible or ambiguous. On the night US clocks spring forward, 02:30 does not exist; when they fall back, 01:30 happens twice. The tool tells you instead of guessing, and uses the earlier of two ambiguous times.

The conversion uses your device's built-in IANA time-zone database, so it is accurate for past dates and near-future dates. For clock-independent timestamps see the Unix Timestamp Converter, and for pure date maths see Date Calculator: Add or Subtract Time.

Assumptions and limits

  • Uses your browser's time-zone data; far-future dates assume today's daylight-saving rules.
  • A short list of widely used zones is offered rather than every zone in the database.
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