HST to SGT Converter
Convert time between Hawaii Standard Time (HST) and Singapore Standard Time (SGT)
Hawaii Standard Time (HST)
Singapore Standard Time (SGT)
Time Difference
Singapore Standard Time (SGT) is 0 hours ahead of Hawaii Standard Time (HST)
Select Date
Select Time
Quick Reference
| HST | SGT |
|---|---|
| 16:00 | 10:00 |
| 18:00 | 12:00 |
| 20:00 | 14:00 |
| 22:00 | 16:00 |
| 00:00 | 18:00 |
| 02:00 | 20:00 |
| 04:00 | 22:00 |
| 06:00 | 00:00 |
| 08:00 | 02:00 |
| 10:00 | 04:00 |
| 12:00 | 06:00 |
| 14:00 | 08:00 |
Top 10 Most Common Time Zones
| Abbreviation | Full Name | UTC Offset | Typical Use |
|---|---|---|---|
| UTC | Coordinated Universal Time | UTC ±0 | Global reference standard (servers, logs, APIs) |
| EST / EDT | Eastern (US) Time | UTC −5 / −4 | New York, Toronto — North American business hub |
| CST / CDT | Central (US) Time | UTC −6 / −5 | Chicago, Dallas — US central business region |
| PST / PDT | Pacific (US) Time | UTC −8 / −7 | San Francisco, Los Angeles — tech industry standard |
| GMT / BST | Greenwich Mean / British Summer Time | UTC 0 / +1 | UK, used globally as a reference with UTC |
| CET / CEST | Central European (Summer) Time | UTC +1 / +2 | Paris, Berlin, Amsterdam — EU business core |
| IST | India Standard Time | UTC +5:30 | India — major IT & outsourcing region |
| CST | China Standard Time | UTC +8 | Beijing, Shanghai — East Asia business hub |
| JST | Japan Standard Time | UTC +9 | Tokyo — finance & tech hub |
| AEST / AEDT | Australian Eastern (Daylight) Time | UTC +10 / +11 | Sydney, Melbourne — APAC regional business |
Why Time Zone Abbreviations Are Ambiguous
Unlike standardized identifiers (like America/New_York or Europe/London from the IANA tz database), abbreviations such as "CST" or "IST" are not globally unique. They can refer to different time zones depending on context — country, region, or even time of year (due to daylight saving time).
Common Ambiguous Time Zone Abbreviations
| Abbrev. | Common Meaning(s) | UTC Offset | Region(s) |
|---|---|---|---|
| CST | Central Standard Time / China Standard Time / Cuba Standard Time | UTC−6 / UTC+8 / UTC−5 | North America, China, Cuba |
| IST | Indian Standard Time / Irish Standard Time / Israel Standard Time | UTC+5:30 / UTC+1 / UTC+2 | India, Ireland, Israel |
| AST | Atlantic Standard Time / Arabia Standard Time | UTC−4 / UTC+3 | Caribbean, Canada, Middle East |
| PST | Pacific Standard Time / Philippine Standard Time | UTC−8 / UTC+8 | North America, Philippines |
| EST | Eastern Standard Time (North America / Australia) | UTC−5 / UTC+10 | North America, Australia |
✅ Best Practice
To avoid ambiguity, always:
- Use IANA tz identifiers — e.g.,
America/New_Yorkinstead of "EST" - Specify UTC offset explicitly — e.g.,
UTC−5when abbreviations must be used - Include the full timezone name — e.g., "Eastern Standard Time (EST)" with UTC offset
About HST to SGT Time Conversion
Converting time between Hawaii Standard Time (HST) and Singapore Standard Time (SGT) is essential for coordinating across one of the largest time gaps in regular use. HST is UTC-10, while SGT is UTC+8 year-round, placing Singapore 18 hours ahead of Hawaii. Neither side observes daylight saving, so the 18-hour offset is constant 365 days a year.
This time zone converter uses the IANA timezone database to ensure accurate calculations. Hawaii skipped DST in 1947, and Singapore has never observed DST, so HST-SGT is one of the most stable cross-Pacific conversions. Whether you're scheduling meetings between Honolulu and Singapore, planning Pacific travel, or coordinating with Singaporean partners from the Hawaiian Islands, our converter provides reliable results.
Common Use Cases for HST to SGT Conversion
Business & Work
- Scheduling meetings between Honolulu offices or partners and Singapore
- Coordinating logistics and shipping across the Asia-Pacific
- Planning conference calls bridging the central Pacific and Southeast Asia
Personal & Travel
- Planning Pacific travel itineraries between Hawaii and Singapore
- Coordinating with family and friends in Singapore
- Scheduling virtual events bridging Hawaii and Asia
Time Zone Information
Hawaii Standard Time (HST)
- UTC Offset: UTC-10
- IANA Timezone: Pacific/Honolulu
- Daylight Saving: No daylight saving time (Hawaii does not observe DST)
- Major Cities: Honolulu, Hilo, Kailua, Kaneohe, Pearl City, Waipahu
- Coverage: State of Hawaii and parts of the central Pacific
Singapore Standard Time (SGT)
- UTC Offset: UTC+8
- IANA Timezone: Asia/Singapore
- Daylight Saving: No daylight saving time (consistent year-round)
- Major Cities: Singapore
- Coverage: Republic of Singapore
Quick Reference: HST to SGT
Remember: SGT is exactly 18 hours ahead of HST, all year. Neither zone observes daylight saving so the offset never changes.
Frequently Asked Questions
What is the time difference between HST and SGT?
Hawaii Standard Time (HST) is UTC-10, while Singapore Standard Time (SGT) is UTC+8. SGT is 18 hours ahead of HST. When it is 12:00 PM in Honolulu, it is 6:00 AM the next day in Singapore.
Does Hawaii observe daylight saving?
No. Hawaii skipped DST in 1947 and stays on HST (UTC-10) year-round. Singapore has never observed DST either, so the HST-SGT offset is a permanent 18 hours.
How does the time difference change throughout the year?
It does not. Because neither side observes DST, the 18-hour gap is constant 365 days a year. Scheduling does not change with the seasons.
What are the best times for HST-SGT business calls?
The overlap is narrow. Honolulu afternoon (3:00 to 5:00 PM HST) maps to Singapore morning (9:00 to 11:00 AM SGT the next day) — workable for both sides. For a Singapore evening, Hawaii early morning (3:00 to 5:00 AM HST) covers 9:00 to 11:00 PM SGT same day Singapore time.
Which countries or regions use SGT?
Singapore Standard Time is used only in the Republic of Singapore. Neighboring Malaysia uses the same UTC+8 offset under the name MYT, and Western Australia uses AWST also at UTC+8.
Which countries or regions use HST?
HST covers the state of Hawaii year-round. Major cities and areas include Honolulu, Hilo, Kailua, Kaneohe, Pearl City and Waipahu. Some parts of the central Pacific use the same offset.
Pro Tips
- • SGT is 18 hours ahead of HST — add 18 hours to Hawaii time and roll the date forward to get Singapore time.
- • Neither HST nor SGT observes DST, so the 18-hour gap is permanent year-round.
- • Honolulu afternoons line up with Singapore mornings the next day — the cleanest cross-Pacific overlap.
- • Always include the date in invites — Singapore is typically a full calendar day ahead of Hawaii.
- • For a same-day Singapore meeting, schedule very early Hawaii morning (3:00 to 5:00 AM HST).
- • Use IANA identifiers Pacific/Honolulu and Asia/Singapore in calendars to stay aligned with regional rules.