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CHAST to BST Converter

CHAST
Chatham Island Standard Time
GMT +12:45
12am
3am
6am
9am
12pm
3pm
6pm
9pm
BST
British Summer Time
GMT +1
12am
3am
6am
9am
12pm
3pm
6pm
9pm

Quick answers

CHAST is 11 hours and 45 minutes ahead of BST. CHAST uses GMT +12:45, and BST uses GMT +1 for this comparison.

For example, 3:30 pm CHAST is 3:45 am BST. Use the converter above to adjust the date or time and create a shareable meeting link.

Best meeting overlap: 6:45pm-7:45pm CHAST, which is 7am-8am BST.

Compare CHAST time with BST time, including current local time, UTC offsets, time difference, daylight saving changes, working hours, and shareable meeting times.

Time Difference

Chatham Island Standard Time is 11 hours and 45 minutes ahead of British Summer Time
3:30 pm15:30 in CHAST is 3:45 am03:45 in BST

CHAST to BST call time
Best time for a conference call or a meeting is between 6:45pm-7:45pm in CHAST which corresponds to 7am-8am in BST

3:30 pm15:30 Chatham Island Standard Time (CHAST). Offset UTC +12:45 hours
3:45 am03:45 British Summer Time (BST). Offset UTC +1:00 hour

3:30 pm15:30 CHAST / 3:45 am03:45 BST

CHASTBST
12am (midnight)12:15 pm
1am1:15 pm
2am2:15 pm
3am3:15 pm
4am4:15 pm
5am5:15 pm
6am6:15 pm
7am7:15 pm
8am8:15 pm
9am9:15 pm
10am10:15 pm
11am11:15 pm
12pm (noon)12:15 am
1pm1:15 am
2pm2:15 am
3pm3:15 am
4pm4:15 am
5pm5:15 am
6pm6:15 am
7pm7:15 am
8pm8:15 am
9pm9:15 am
10pm10:15 am
11pm11:15 am
00:0012:15
01:0013:15
02:0014:15
03:0015:15
04:0016:15
05:0017:15
06:0018:15
07:0019:15
08:0020:15
09:0021:15
10:0022:15
11:0023:15
12:0000:15
13:0001:15
14:0002:15
15:0003:15
16:0004:15
17:0005:15
18:0006:15
19:0007:15
20:0008:15
21:0009:15
22:0010:15
23:0011:15

Chatham Island Standard Time

Offset: CHAST is 12 hours and 45 minutes ahead Greenwich Mean Time (GMT) and is used in Pacific

Countries using this time zone: New Zealand

CHAST Time Zone Geo Map
CHAST timezone map

Daylight Saving: This is a standard time zone. During summer, some places set clocks forward one hour for daylight saving time and observe Chatham Island Daylight Time (CHADT).

Start: Chatham Island Standard Time (CHAST) started on Sunday, April 5, 2026 at 3:45 am local time and clocks were set one hour back to Sunday, April 5, 2026, 2:45 am. Standard time starts annually on the first Sunday of April.

End: Chatham Island Standard Time (CHAST) ends on Sunday, September 27, 2026 at 2:45 am local time and clocks are set one hour forward to Sunday, September 27, 2026, 3:45 am local daylight time instead. Standard time ends annually on the last Sunday of September.

CHAST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • +1245 - basic
  • +12:45 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • +1245 - sign character (+) followed by a four digit time providing hours (12) and minutes (45) of the offset. Indicates an offset of twelve hours and forty-five minutes to the east of the zero meridian.

British Summer Time

Offset: BST is 1 hour ahead Greenwich Mean Time (GMT) and is used in Europe

Countries using this time zone: Britain (UK), Guernsey, Isle of Man, Jersey

Principal Cities: The largest city in the BST time zone is London in United Kingdom, with about 7.557 million people. Other major cities in this time zone include Birmingham, Glasgow, Liverpool, Saint Helier.

BST Time Zone Geo Map
BST timezone map

Daylight Saving: British Summer Time (BST) is a daylight saving/summer time zone. During winter, some places set clocks back one hour and observe Greenwich Mean Time (GMT).

Daylight saving time clock moves forward for one hour from 1am to 2amStart: British Summer Time (BST) started on Sunday, March 29, 2026 at 1:00 am local time and clocks were set one hour forward to Sunday, March 29, 2026, 2:00 am. Daylight saving starts annually on the last Sunday of March

Daylight saving time clock moves back for one hour from 2am to 1amEnd: British Summer Time (BST) ends on Sunday, October 25, 2026 at 2:00 am local time and clocks are set one hour back to Sunday, October 25, 2026, 1:00 am local standard time instead. Daylight saving ends annually on the last Sunday of October

BST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • +01 - basic short
  • +0100 - basic
  • +01:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • +0100 - sign character (+) followed by a four digit time providing hours (01) and minutes (00) of the offset. Indicates an offset of one hour to the east of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Alpha - Military abbreviation for BST
  • A - short form of 'Alpha'
IANA/Olson: Reflects BST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • Europe/Belfast
  • Europe/Guernsey
  • Europe/Isle_of_Man
  • Europe/Jersey
  • Europe/London
  • GB
  • GB-Eire
BST Abbreviation: Several time zones share BST abbreviation and it could refer to these time zones
  • British Summer Time - UTC +1
  • Bangladesh Standard Time - UTC +6
  • Bougainville Standard Time - UTC +11
Time zones with the GMT +1 offset:
  • BST - British Summer Time
  • CET - Central European Time
  • IST - Irish Standard Time
  • WEST - Western European Summer Time
  • A - Alpha Time Zone
  • CET - Central European Time
  • MEZ - Mitteleuropäische Zeit
  • WAT - West Africa Time
  • WST - Western Sahara Summer Time
  • BMT - Biel Mean Time
EST to ISTGMT to ESTPST to ESTEST to GMTPST to GMT