Civil Time AtlasIANA time zone data

Historically distinct IANA time zone

Asia/Kolkata

Canonical IANA identifier · Data release 2026c

Local time now IST · current offset
Countries
India
GPS reference
22.53° N, 88.37° E
Data source
IANA asia
Aliases
Asia/Calcutta
Rule groups

Geographic context

Where this clock belongs

The map marks the IANA reference location and associated country, not a time-zone boundary.

World location
Regional context

GPS reference: 22.53° N, 88.37° E. Associated countries: IN.

The Wikipedia link provides additional context; it is not evidence for a historical claim. Transition data comes from the IANA source file.

Civil-time record

Recorded changes over time

From 1854 to 1945 · 7 recorded transitions

Recurring daylight-saving changes are grouped separately when JavaScript is available.

Notable changes

One-off changes and transitions outside the recurring seasonal rhythm.

  1. +05:53 · HMTStandard time applies
  2. +05:21 · MMTStandard time applies
  3. +05:30 · ISTStandard time applies
  4. +06:30 · +0630Daylight saving time begins
  5. +05:30 · ISTStandard time applies
  6. +06:30 · +0630Daylight saving time begins
Browse every recorded transition
Local time after transitionOffset afterAbbreviationRule
1854-06-27 23:59+05:53HMTStandard time
1869-12-31 23:27+05:21MMTStandard time
1906-01-01 00:08+05:30ISTStandard time
1941-10-01 01:00+06:30+0630Daylight saving time
1942-05-14 23:00+05:30ISTStandard time
1942-09-01 01:00+06:30+0630Daylight saving time
1945-10-14 23:00+05:30ISTStandard time