HST to ACST Converter
Trying to line up HST and ACST? ACST is 19 hours and 30 minutes ahead of HST. Set any HST time below to see the matching ACST time and date.
Daylight saving notes
In southern Australia, daylight saving time runs from the first Sunday in October to the first Sunday in April. That affects Australian Central Standard Time (ACST).
HST to ACST conversion chart
For example, a 9:00 AM HST meeting takes place at 4:30 AM ACST (+1 day). Concretely, when Honolulu (HST) and Adelaide (ACST) set up a call, aCST is 19 hours and 30 minutes ahead of HST.
| HST time | ACST time |
|---|---|
| 12:00 AM | 7:30 PM |
| 1:00 AM | 8:30 PM |
| 2:00 AM | 9:30 PM |
| 3:00 AM | 10:30 PM |
| 4:00 AM | 11:30 PM |
| 5:00 AM | 12:30 AM+1 day |
| 6:00 AM | 1:30 AM+1 day |
| 7:00 AM | 2:30 AM+1 day |
| 8:00 AM | 3:30 AM+1 day |
| 9:00 AM | 4:30 AM+1 day |
| 10:00 AM | 5:30 AM+1 day |
| 11:00 AM | 6:30 AM+1 day |
| 12:00 PM | 7:30 AM+1 day |
| 1:00 PM | 8:30 AM+1 day |
| 2:00 PM | 9:30 AM+1 day |
| 3:00 PM | 10:30 AM+1 day |
| 4:00 PM | 11:30 AM+1 day |
| 5:00 PM | 12:30 PM+1 day |
| 6:00 PM | 1:30 PM+1 day |
| 7:00 PM | 2:30 PM+1 day |
| 8:00 PM | 3:30 PM+1 day |
| 9:00 PM | 4:30 PM+1 day |
| 10:00 PM | 5:30 PM+1 day |
| 11:00 PM | 6:30 PM+1 day |
This chart uses the fixed HST and ACST offsets; the live converter above follows current daylight saving.
Convert HST to ACST Time Zone
Below are the answers people search for most when converting Hawaii Standard Time (HST) to Australian Central Standard Time (ACST).
How do I convert HST to ACST?
It takes three quick steps:
- Click the HST field on the left and pick the time you want to convert.
- The matching ACST time updates on the right automatically — there’s no button to press.
- Need a different day? Click the date field and the result follows, rolling over if it crosses midnight.
What is the time difference between HST and ACST?
ACST is 19 hours and 30 minutes ahead of HST. In everyday terms, once you know the time on one side you just add 19 hours 30 min to get the other — so a call between Honolulu and Adelaide is always 19 hours 30 min apart.
What's the current time in ACST?
Right now the time in Australian Central Standard Time (ACST) is Tuesday, June 30, 2026 · 3:23:57 AM. It ticks every second, so you’re always looking at the live ACST clock.
And what time is it in HST?
And in Hawaii Standard Time (HST), it’s currently Monday, June 29, 2026 · 7:53:57 AM. Compare the two and the 19 hours 30 min gap is easy to see.
Planning a meeting across HST and ACST?
For example, a 9:00 AM HST meeting takes place at 4:30 AM ACST (+1 day). The trick is to aim for a slot that lands inside normal working hours on both sides. Once you’ve found a time, hit Share on the converter to copy a link with the time built in — easy to send to a colleague. Juggling three or more zones? The meeting planner highlights the hours that overlap for everyone.
Does daylight saving time change the HST–ACST difference?
The labels HST and ACST are fixed offsets, so the result on this page is always exact. One side switches between standard and summer time while the other stays put, so the real-world gap can shift by an hour for part of the year. It's worth checking which label a region is actually using before you lock in a time.
How accurate is this HST to ACST conversion?
We don’t guess. HST and ACST times are worked out from the official IANA time zone database, the trusted standard that operating systems use worldwide. Because daylight-saving rules and regional offsets do change over time, we track those updates rather than relying on a fixed number — which is exactly where many converters slip up.
Convert HST to other time zones
- UTC Coordinated Universal Time
- GMT Greenwich Mean Time
- EST Eastern Standard Time
- EDT Eastern Daylight Time
- CST Central Standard Time
- CDT Central Daylight Time
- MST Mountain Standard Time
- MDT Mountain Daylight Time
- PST Pacific Standard Time
- PDT Pacific Daylight Time
- AKST Alaska Standard Time
- AKDT Alaska Daylight Time
- AST Atlantic Standard Time
- ADT Atlantic Daylight Time
- NST Newfoundland Standard Time
- NDT Newfoundland Daylight Time
- BRT Brasília Time
- ART Argentina Time
- WET Western European Time
- WEST Western European Summer Time
- CET Central European Time
- CEST Central European Summer Time
- EET Eastern European Time
- EEST Eastern European Summer Time
- BST British Summer Time
- IST Irish Standard Time
- MSK Moscow Standard Time
- TRT Turkey Time
- WAT West Africa Time
- CAT Central Africa Time
- EAT East Africa Time
- SAST South Africa Standard Time
- GST Gulf Standard Time
- IST Israel Standard Time
- IDT Israel Daylight Time
- IST India Standard Time
- PKT Pakistan Standard Time
- BDT Bangladesh Standard Time
- ICT Indochina Time
- WIB Western Indonesian Time
- WITA Central Indonesian Time
- WIT Eastern Indonesian Time
- CST China Standard Time
- HKT Hong Kong Time
- SGT Singapore Time
- PHT Philippine Time
- JST Japan Standard Time
- KST Korea Standard Time
- AWST Australian Western Standard Time
- ACST Australian Central Standard Time
- ACDT Australian Central Daylight Time
- AEST Australian Eastern Standard Time
- AEDT Australian Eastern Daylight Time
- NZST New Zealand Standard Time
- NZDT New Zealand Daylight Time
Convert to ACST from other time zones
- UTC Coordinated Universal Time
- GMT Greenwich Mean Time
- EST Eastern Standard Time
- EDT Eastern Daylight Time
- CST Central Standard Time
- CDT Central Daylight Time
- MST Mountain Standard Time
- MDT Mountain Daylight Time
- PST Pacific Standard Time
- PDT Pacific Daylight Time
- AKST Alaska Standard Time
- AKDT Alaska Daylight Time
- HST Hawaii Standard Time
- AST Atlantic Standard Time
- ADT Atlantic Daylight Time
- NST Newfoundland Standard Time
- NDT Newfoundland Daylight Time
- BRT Brasília Time
- ART Argentina Time
- WET Western European Time
- WEST Western European Summer Time
- CET Central European Time
- CEST Central European Summer Time
- EET Eastern European Time
- EEST Eastern European Summer Time
- BST British Summer Time
- IST Irish Standard Time
- MSK Moscow Standard Time
- TRT Turkey Time
- WAT West Africa Time
- CAT Central Africa Time
- EAT East Africa Time
- SAST South Africa Standard Time
- GST Gulf Standard Time
- IST Israel Standard Time
- IDT Israel Daylight Time
- IST India Standard Time
- PKT Pakistan Standard Time
- BDT Bangladesh Standard Time
- ICT Indochina Time
- WIB Western Indonesian Time
- WITA Central Indonesian Time
- WIT Eastern Indonesian Time
- CST China Standard Time
- HKT Hong Kong Time
- SGT Singapore Time
- PHT Philippine Time
- JST Japan Standard Time
- KST Korea Standard Time
- AWST Australian Western Standard Time
- ACDT Australian Central Daylight Time
- AEST Australian Eastern Standard Time
- AEDT Australian Eastern Daylight Time
- NZST New Zealand Standard Time
- NZDT New Zealand Daylight Time
Frequently asked questions
How many hours ahead of HST is ACST?
ACST is 19 hours and 30 minutes ahead of HST — a fixed 19 hours and 30 minutes difference, since both are fixed-offset labels.
What time is it in ACST when it's 12:00 PM HST?
When it's 12:00 PM (noon) HST, it's 7:30 AM ACST the next day.
Do HST or ACST use daylight saving time?
Hawaii Standard Time (HST) is a fixed offset with no daylight saving; Australian Central Standard Time (ACST) observes daylight saving, alternating with ACDT.
Why might the real-world HST–ACST difference change during the year?
The labels HST and ACST are fixed offsets, so this converter is always exact. But Australian Central Standard Time's region switches between standard and summer time, so for part of the year you may actually want HST to ACDT. Always check which label a region is currently using before you schedule.