Time zone converter for international meetings, travel, and global team coordination. Supports 30+ world cities with automatic DST handling.
Four tabs: time conversion (city A โ city B), meeting planner across multiple zones (up to five cities), real-time world clock, and jet-lag forecast based on travel direction (east-west vs. west-east).
Disclaimer: DST is computed automatically from IANA timezone data. Double-check for important events.
Calculator information
๐ How to use this calculator
- Pick the source city (e.g. New York, EST UTC-5) and the destination city (e.g. London GMT UTC+0).
- Enter the source date and time in 24-hour format, e.g. 14:30, or 2:30 PM.
- Click Convert; results automatically account for DST (Daylight Saving Time) for US and European cities.
- For multi-city meetings, use the Meeting Planner tab; add up to 5 time zones.
- Check the World Clock tab for live global time, or the Jet Lag tab for an estimated recovery time.
- For travel, the jet lag rule of thumb is East-West 1 day/zone and West-East 1.5 days/zone.
๐งฎ UTC Conversion and Jet Lag Estimation
Time_dest = Time_source + (UTC_dest - UTC_source) ยฑ DST_offset ; JetLag_days = |ฮTZ| ร factor (East = 1.5, West = 1.0)
- Time_source = time in the origin zone
- UTC_dest, UTC_source = UTC offset of destination and origin zones (hours)
- DST_offset = +1 hour if the destination city is currently observing DST
- ฮTZ = difference in number of time zones between origin and destination
Most of the US observes DST starting the second Sunday of March and ending the first Sunday of November. Europe observes DST from late March to late October. Hawaii, most of Arizona, and US territories do not observe DST.
๐ก Worked example: Meeting from New York 9:00 AM to London (October, BST UTC+1)
Given:- Source city: New York (EDT UTC-4, on DST)
- Destination city: London
- Date: October 15 (still BST before October 27)
- Source time: 9:00 AM EDT
Steps:- BST in London = UTC+1
- Difference = +1 - (-4) = +5 hours
- Time_London = 9:00 AM + 5 hours = 2:00 PM BST
- Check: 2:00 PM BST = within business hours
- Meeting works well at this time for both parties
Result: 9:00 AM EDT = 2:00 PM BST. This is a workable meeting slot during business hours on both sides of the Atlantic.
โ Frequently asked questions
Why does the US observe DST?
DST was first adopted in the US during World War I to conserve energy and extended by the Uniform Time Act of 1966. It moves one hour of daylight from morning to evening during the warmer half of the year. The benefit is most noticeable at mid-to-high latitudes (>30ยฐ) with significant day-length variation. Hawaii and most of Arizona opt out because their proximity to the equator or extreme heat makes the shift unnecessary.
When does DST start and end in the US and Europe?
US and Canada: DST begins the second Sunday of March at 2:00 AM (spring forward 1 hour) and ends the first Sunday of November at 2:00 AM (fall back 1 hour). Europe: DST begins the last Sunday of March at 01:00 UTC and ends the last Sunday of October at 01:00 UTC. Australia is reversed: October-April because of the southern hemisphere.
What is the best time zone window for Asia-Europe-Americas meetings?
The 'golden hours' window that overlaps APAC, EMEA, and the Americas is 13:00-15:00 UTC. That equals 8:00-10:00 AM New York, 14:00-16:00 London, and 21:00-23:00 Singapore. For recurring global meetings, rotating the meeting time across zones helps distribute the burden of early-morning or late-evening calls.
How long does it take to recover from jet lag?
Rule of thumb: east-to-west travel typically takes 1 day per time zone, while west-to-east takes about 1.5 days per zone. Eastward travel is harder because the human circadian rhythm naturally runs around 24.2 hours and prefers to delay. Strategies: morning sunlight exposure at the destination, melatonin 0.5-3 mg on the first night, and fasting before local bedtime.
How do I manage time zone differences when working remotely across countries?
Use asynchronous communication (Loom, Notion) as the default. Set 2-3 hours of mandatory overlap (core hours) per week for synchronous meetings. Record times in your calendar in UTC or use tools like World Time Buddy. Always state deadlines with explicit time zones, e.g. '5:00 PM ET Friday'.
๐ Sources & references
Last updated: May 11, 2026