AST to HST Time Converter
HST is 7 hours behind AST. Atlantic Canada and the Caribbean are currently on ADT (UTC-3:00), and HST is UTC-10:00.
Best Time to Call Between AST and HST
Both zones are inside normal business hours between 4:00 PM and 5:00 PM AST — that's 9:00 AM to 10:00 AM HST. That's a 1-hour window.
both at work AST only HST only neither — hours along the strip are AST.
Common Times Converted
AST on the left, HST on the right.
AST to HST: Full 24-Hour Conversion Table
Shaded rows are working hours; the darker shade marks the hours when both zones are at work.
| AST | HST | Working hours |
|---|---|---|
| 12:00 AM | 5:00 PM prev day | — |
| 1:00 AM | 6:00 PM prev day | — |
| 2:00 AM | 7:00 PM prev day | — |
| 3:00 AM | 8:00 PM prev day | — |
| 4:00 AM | 9:00 PM prev day | — |
| 5:00 AM | 10:00 PM prev day | — |
| 6:00 AM | 11:00 PM prev day | — |
| 7:00 AM | 12:00 AM | — |
| 8:00 AM | 1:00 AM | — |
| 9:00 AM | 2:00 AM | AST only |
| 10:00 AM | 3:00 AM | AST only |
| 11:00 AM | 4:00 AM | AST only |
| 12:00 PM | 5:00 AM | AST only |
| 1:00 PM | 6:00 AM | AST only |
| 2:00 PM | 7:00 AM | AST only |
| 3:00 PM | 8:00 AM | AST only |
| 4:00 PM | 9:00 AM | Both zones |
| 5:00 PM | 10:00 AM | HST only |
| 6:00 PM | 11:00 AM | HST only |
| 7:00 PM | 12:00 PM | HST only |
| 8:00 PM | 1:00 PM | HST only |
| 9:00 PM | 2:00 PM | HST only |
| 10:00 PM | 3:00 PM | HST only |
| 11:00 PM | 4:00 PM | HST only |
What AST and HST Actually Are
AST — Atlantic Standard Time
Halifax, San Juan, Santo Domingo, Bermuda. Standing at UTC-4:00 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, November 1, 2026, to AST. AST also stands for Arabia Standard Time (UTC+3), used in Saudi Arabia, Iraq and Kuwait.
Atlantic Standard Time is the only North American zone whose name is more commonly associated, worldwide, with a completely different zone — Arabia Standard Time.
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.
What This Means in Practice
This gap is not fixed
AST 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, November 1, 2026 unless someone resets it.
Major Cities in Each Zone
Cities on AST
Cities on HST
Frequently Asked Questions
What is the time difference between AST and HST?
HST is 7 hours behind AST. That is the live figure. Taken strictly as written, the gap between AST and HST is 6 hours — the two differ because at least one of these regions is currently on daylight saving.
What is 9:00 AM AST in HST?
9:00 AM AST is 2:00 AM HST.
What are the best hours to schedule a call between AST and HST?
Between 4:00 PM and 5:00 PM AST, which is 9:00 AM to 10:00 AM HST. Both sides are inside normal business hours through that window.
Does the difference between AST and HST change during the year?
Yes. AST 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, November 1, 2026.
Does AST always mean Atlantic Standard Time?
AST also stands for Arabia Standard Time (UTC+3), used in Saudi Arabia, Iraq and Kuwait.
Does HST always mean Hawaii Standard Time?
Hawaii does not observe daylight saving, so this offset holds all year.