Quick answer
Pick a base city (Hanoi by default), enter a date and time, and see the matching time in Tokyo, Sydney, London, New York, Los Angeles and any city you add. Daylight saving time is applied for the exact date: 9:00 in Hanoi on 15 January is 21:00 the previous evening in New York, but on 15 July it is 22:00. The meeting planner colours everyone's working hours so you can find a slot that suits all.
What are time zones and daylight saving?
Booking a call with a US client, catching a sale that opens in Seoul, phoning family in Australia: adding or subtracting hours by hand goes wrong because countries switch to daylight saving on different dates and some are offset by half an hour (India is +5:30). This tool asks your browser's built-in IANA time zone data, the same data your phone uses to set its clock.
How to convert between time zones
- 1
Choose the city whose time you know under “Base time in”. The current date and time are filled in.
- 2
Edit the date and time. Each card shows the time in that city, with “Previous day / Next day” when the date differs.
- 3
Add cities with “Add a city” (type English or Vietnamese names, or a country) and remove them with X.
- 4
In the meeting planner, drag the slider or click a column to find an hour that is green (working hours) everywhere.
- 5
Use “Copy all times” to paste the list into an invitation.
Offsets from Vietnam (UTC+7)
| Place | Zone | Northern winter (January) | Northern summer (July) |
|---|---|---|---|
| Tokyo, Seoul | UTC+9 | 2 hours ahead | 2 hours ahead |
| Beijing, Singapore | UTC+8 | 1 hour ahead | 1 hour ahead |
| Sydney | UTC+11 / +10 | 4 hours ahead | 3 hours ahead |
| New Delhi | UTC+5:30 | 1 h 30 behind | 1 h 30 behind |
| London | UTC+0 / +1 | 7 hours behind | 6 hours behind |
| Paris, Berlin | UTC+1 / +2 | 6 hours behind | 5 hours behind |
| New York | UTC−5 / −4 | 12 hours behind | 11 hours behind |
| Los Angeles | UTC−8 / −7 | 15 hours behind | 14 hours behind |
Swipe sideways to see the whole table →
Sydney's summer is the opposite of the northern hemisphere: daylight saving runs from October to April.
Examples
Meeting New York
9:00 Monday in Hanoi (January) is 21:00 Sunday in New York. A slot that suits both is usually 20:00–22:00 Hanoi, 8:00–10:00 New York.
Calling Sydney
In December 19:00 in Hanoi is 23:00 in Sydney; in June it is 22:00 because Sydney is back on standard time.
A sale opening in Seoul
10:00 in Seoul is 8:00 in Vietnam all year, because Korea does not use daylight saving.
An exam scheduled in UTC
Add UTC, make it the base city and enter the time: the Hanoi card shows local time (UTC plus 7 hours).
Common mistakes
- Using one fixed offset all year.
- The US, Europe and Australia change clocks on different dates, so the gap to Vietnam moves by an hour with the seasons. Convert for the actual date.
- Forgetting the date changes.
- Morning in Asia is often the previous evening in the Americas. Check the “Previous day / Next day” label.
- Sending an invite without a time zone.
- Always state the zone (21:00 ICT / 9:00 EST) or paste the list from the copy button.
- Picking a time that doesn't exist.
- On the day clocks spring forward, 2:30 never happens; the tool treats it as the moment just after the jump.
How daylight saving works
Many temperate countries move clocks forward one hour in summer. The US and Canada switch on the second Sunday of March and back on the first Sunday of November; the EU and UK switch on the last Sundays of March and October. Because these dates differ, New York and London are only four hours apart for a few weeks each year.
Vietnam, Japan, Korea, China, Singapore and India do not observe daylight saving.
Where the data comes from
The tool doesn't keep its own offset table. It asks the browser through Intl, which uses the IANA time zone database updated with your browser and operating system, so daylight saving rules, including recent changes, are applied correctly.
Glossary
- UTC
- Coordinated Universal Time, the reference for all time zones. Vietnam is UTC+7.
- ICT
- Indochina Time (UTC+7), used in Vietnam, Laos, Cambodia and Thailand.
- DST
- Daylight saving time: clocks run one hour ahead in summer.
- IANA
- The body that maintains the time zone database (e.g. Asia/Ho_Chi_Minh) used by computers and phones.
Frequently asked questions
What time zone is Vietnam in?
UTC+7 (Indochina Time). The whole country uses one zone with no daylight saving.
How far behind is the US?
The East Coast (New York) is 12 hours behind in winter and 11 in summer; the West Coast (Los Angeles) is 15 and 14 hours behind.
How far ahead are Japan and Korea?
Two hours, all year.
Does the tool update by itself?
The “Now in…” line ticks every second. The base date and time only change when you edit them or press “Back to now”.
Why are some places 30 or 45 minutes off?
Some countries use fractional zones, such as India (UTC+5:30) and Nepal (UTC+5:45). They are shown exactly.
Is my city list saved?
No. Everything runs in your browser; reloading resets the default list.
Ratings and comments
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