Convert any time between HST and AEST, with a full 24-hour table and the hours when both sides are actually at work.

HST to AEST Time Converter

AEST is 21 hours ahead of HST. HST is UTC-10:00, and Eastern Australia is currently on AEDT (UTC+11:00).

Worth knowing right now. Eastern Australia is currently on AEDT, not AEST, because daylight saving is in effect. The 21 hours above is the gap between those two regions today, which is almost certainly what you want. Taken strictly as written, HST to AEST is 20 hours.
HST
Hawaii Standard Time
05:45:47 AM
Sunday, October 11, 2026
UTC-10:00
+21:00
hours difference
⇆ Reverse
AEST
Australian Eastern Standard Time
02:45:47 AM
Monday, October 12, 2026
UTC+11:00

Best Time to Call Between HST and AEST

Both zones are inside normal business hours between 12:00 PM and 5:00 PM HST — that's 9:00 AM to 2:00 PM AEST. That's a 5-hour window.

both at work HST only AEST only neither  —  hours along the strip are HST.

HST to AEST: Full 24-Hour Conversion Table

Shaded rows are working hours; the darker shade marks the hours when both zones are at work.

HSTAESTWorking hours
12:00 AM 9:00 PM —
1:00 AM 10:00 PM —
2:00 AM 11:00 PM —
3:00 AM 12:00 AM next day —
4:00 AM 1:00 AM next day —
5:00 AM 2:00 AM next day —
6:00 AM 3:00 AM next day —
7:00 AM 4:00 AM next day —
8:00 AM 5:00 AM next day —
9:00 AM 6:00 AM next day HST only
10:00 AM 7:00 AM next day HST only
11:00 AM 8:00 AM next day HST only
12:00 PM 9:00 AM next day Both zones
1:00 PM 10:00 AM next day Both zones
2:00 PM 11:00 AM next day Both zones
3:00 PM 12:00 PM next day Both zones
4:00 PM 1:00 PM next day Both zones
5:00 PM 2:00 PM next day AEST only
6:00 PM 3:00 PM next day AEST only
7:00 PM 4:00 PM next day AEST only
8:00 PM 5:00 PM next day —
9:00 PM 6:00 PM next day —
10:00 PM 7:00 PM next day —
11:00 PM 8:00 PM next day —

What HST and AEST Actually Are

HST — Hawaii Standard Time

Honolulu and the rest of Hawaii. Standing at UTC-10:00 as written, and the region does not change its clocks, so that offset holds all year. Hawaii does not observe daylight saving, so this offset holds all year.

Hawaii dropped daylight saving in 1967 and never resumed it. Being close to the equator, its daylight barely varies across the year, so there is little to gain.

AEST — Australian Eastern Standard Time

Sydney, Melbourne, Brisbane, Canberra, Hobart. Standing at UTC+10:00 as written, and the region does change its clocks, so its live offset moves by an hour twice a year. The next change is on Sunday, April 4, 2027, to AEST. Sydney and Melbourne move to AEDT (UTC+11) for the southern summer; Brisbane does not change at all.

Queensland abandoned daylight saving after a 1992 referendum, so for five months a year Brisbane and Sydney read different clocks despite sharing a zone.

What This Means in Practice

The date changes mid-working-day

For 8 of the eight hours in a normal HST working day, the equivalent AEST time falls on a different calendar date. Anything scheduled in that stretch needs the date checked as well as the time, or a Tuesday call quietly becomes a Wednesday one at the other end.

This gap is not fixed

AEST changes its clocks and HST does not, so the difference between them moves by an hour twice a year. A recurring meeting set now will drift for one side from Sunday, April 4, 2027 unless someone resets it.

Nearly opposite sides of the clock

At 21 hours apart, one side's morning is the other side's night. Handing work over at the end of a shift usually beats trying to get both parties in the same call.

Frequently Asked Questions

What is the time difference between HST and AEST?

AEST is 21 hours ahead of HST. That is the live figure. Taken strictly as written, the gap between HST and AEST is 20 hours — the two differ because at least one of these regions is currently on daylight saving.

What is 9:00 AM HST in AEST?

9:00 AM HST is 6:00 AM the next day AEST.

What are the best hours to schedule a call between HST and AEST?

Between 12:00 PM and 5:00 PM HST, which is 9:00 AM to 2:00 PM AEST. Both sides are inside normal business hours through that window.

Does the difference between HST and AEST change during the year?

Yes. AEST observes daylight saving and HST does not, so the gap shifts by an hour at least twice a year. The next clock change is on Sunday, April 4, 2027.

Does HST always mean Hawaii Standard Time?

Hawaii does not observe daylight saving, so this offset holds all year.

Does AEST always mean Australian Eastern Standard Time?

Sydney and Melbourne move to AEDT (UTC+11) for the southern summer; Brisbane does not change at all.

Converting between two time zones regularly? Bookmark this page — the clocks update live and the table follows daylight saving automatically.