CHAST — Chatham Island Standard Time
See what CHAST means, where it is used, its UTC+12:45 offset, and how to compare or convert it with other time zones.
How to Convert CHAST to Other Time Zones
Open the CHAST converter page: Go to https://www.xconvert.com/time-converter/chast-time-zone to load the visual comparison grid with Chatham Island Standard Time (CHAST) already shown as the base row. This page is especially useful if you are planning a call with someone on the Chatham Islands, coordinating marine operations east of mainland New Zealand, or checking whether a meeting overlaps normal office hours in larger hubs like Auckland, Sydney, or London.
Add comparison cities with the + Add City button: Click “+ Add City” and search for cities such as Auckland, Wellington, Sydney, or London depending on your use case. Auckland and Wellington are relevant because the Chatham Islands are part of New Zealand but run on a distinct offset, while Sydney is useful for aviation, tourism, and regional business coordination, and London helps global teams compare CHAST against major financial-market hours.
Drag across the grid to select a meeting window: Click “Select” if needed, then drag across the CHAST row to highlight a time range in purple, such as 9:00 AM to 11:00 AM CHAST. That selection immediately shows the equivalent time in other rows—for example, 9:00 AM CHAST is 8:15 AM in Auckland during New Zealand Standard Time, which helps confirm whether a morning call on the Chatham Islands still fits mainland New Zealand work hours.
Export or share the selected time range: After selecting the range, use the export options for ICS download, Google Calendar, Gmail, Copy to clipboard, or Share link. This is practical when sending a confirmed cross-time-zone slot to a remote team, a travel coordinator, or a client so each person sees the event in their own local time without manually converting the unusual UTC+12:45 offset.
About Chatham Island Standard Time (CHAST)
CHAST stands for Chatham Island Standard Time, a time standard used in the Chatham Islands, a remote part of New Zealand located in the Pacific Ocean southeast of the New Zealand mainland. Its exact offset is UTC+12:45, which makes it one of the world’s few official time zones that uses a 45-minute offset rather than a whole hour.
Because CHAST is 12 hours and 45 minutes ahead of Coordinated Universal Time, when it is 12:00 noon UTC, it is 12:45 AM the next day in CHAST. This unusual offset matters for scheduling because it does not line up neatly with the hour-based assumptions built into many manual planning habits, so visual comparison is especially useful when arranging calls, transport timing, or deadline handoffs.
CHAST is used specifically in the Chatham Islands region of New Zealand, rather than across the whole country. Mainland New Zealand typically uses NZST (UTC+12) in standard time, so CHAST is 45 minutes ahead of mainland New Zealand standard time, meaning that when it is 9:00 AM in Wellington during NZST, it is 9:45 AM on the Chatham Islands.
The Chatham Islands have a small population compared with mainland urban centers, but the time zone remains important for local government, aviation schedules, logistics, fisheries, tourism planning, and communications with mainland New Zealand. Anyone booking flights, arranging service windows, or planning public-sector coordination with the islands should account for the extra 45 minutes rather than assuming the same clock time as Auckland or Christchurch.
CHAST and Daylight Saving Time
Although the input details list DST: false, in real-world usage Chatham Island Standard Time does have a daylight saving counterpart. During the daylight saving season, the Chatham Islands switch from CHAST (UTC+12:45) to CHADT, Chatham Island Daylight Time (UTC+13:45), moving clocks forward by 1 hour.
For the current year, 2026, the Chatham Islands observe daylight saving on the New Zealand seasonal pattern adjusted for their local zone. Clocks switch from CHADT back to CHAST on Sunday, 5 April 2026 at 3:45 AM local daylight time, when they move back to 2:45 AM CHAST, and they switch from CHAST to CHADT on Sunday, 27 September 2026 at 2:45 AM local standard time, when clocks move forward to 3:45 AM CHADT.
This seasonal change affects meeting planning in a very specific way: during standard time, the islands are 45 minutes ahead of mainland New Zealand, but during daylight saving they remain offset in parallel at UTC+13:45, still preserving the distinctive 45-minute difference from many other regions. If you are scheduling recurring calls with teams in New Zealand, Australia, Asia, Europe, or North America, check the date row in the converter before confirming a slot, because the exact difference can shift when one region has changed clocks and another has not.
Frequently Asked Questions
What does CHAST stand for?
CHAST stands for Chatham Island Standard Time. It is the standard-time zone used on the Chatham Islands of New Zealand, and its official offset is UTC+12:45, which is unusual because it includes a 45-minute component rather than a whole-hour difference.
Is CHAST the same as GMT?
No, CHAST is not the same as GMT. GMT is UTC+0, while CHAST is UTC+12:45, so CHAST is 12 hours and 45 minutes ahead of GMT; for example, when it is 6:00 AM GMT, it is 6:45 PM CHAST on the same day.
Which cities use CHAST?
CHAST is associated with the Chatham Islands, rather than a large list of major international cities. The principal settlement most commonly referenced is Waitangi, Chatham Islands, and the time zone is used across the island group for local administration, transport timing, and daily business operations.
What is the UTC offset for CHAST?
The UTC offset for CHAST is UTC+12:45. That means you add 12 hours and 45 minutes to UTC to get local standard time on the Chatham Islands, so 10:00 PM UTC becomes 10:45 AM CHAST the next day.
When does CHAST change?
CHAST changes when the Chatham Islands enter or leave daylight saving time. In 2026, the islands change to CHAST on 5 April 2026 when clocks move back from CHADT (UTC+13:45), and change from CHAST to CHADT on 27 September 2026 when clocks move forward by one hour.
Is CHAST the same as New Zealand time?
No, CHAST is not exactly the same as mainland New Zealand time. During standard time, mainland New Zealand uses NZST (UTC+12) while the Chatham Islands use CHAST (UTC+12:45), so the islands are 45 minutes ahead; when it is 8:00 AM in Auckland, it is 8:45 AM on the Chatham Islands.
Why does CHAST use a 45-minute offset?
CHAST uses a 45-minute offset because the Chatham Islands maintain a distinct local time standard separate from mainland New Zealand. This arrangement reflects the islands’ geographic and administrative history and is important in practice because transport schedules, local services, and inter-island coordination would be inaccurate if people rounded the time difference to a full hour.
How do I schedule a meeting with someone in CHAST?
The easiest method is to use the xconvert visual grid and compare CHAST with the other participant’s city before sending an invite. Because CHAST is UTC+12:45, a time such as 2:00 PM CHAST may map to 1:15 PM in Auckland during NZST or a very different previous-day time in North America, so dragging a visual range and exporting it to Google Calendar or ICS reduces mistakes caused by the quarter-hour offset.