Timezone Converter: Tips & How-Tos

Best Practices

Always confirm DST status before scheduling. Daylight saving time transitions happen on different dates in the US, EU, and Australia. A meeting set for '3 pm EST' becomes '3 pm EDT' after the spring transition without any indication in the invite.
Use city names, not timezone abbreviations. EST and EDT both exist; IST is shared by India, Ireland, and Israel. Choose a city name (New York, Dublin, Mumbai) to avoid ambiguity when sending calendar invites internationally.
Anchor to UTC when sending global notifications. For developer alerts, release announcements, or compliance-sensitive events, state the time in UTC alongside local conversions. UTC never changes and has no DST.
Share the time in the recipient's local zone. When inviting someone to a meeting, state the time in their time zone first, then yours in parentheses. This reduces cognitive load and prevents them from making the conversion themselves under pressure.
Add a 30-minute buffer around DST transition dates. During the two weeks when US and EU DST transitions are out of sync, recurring meetings can shift by an hour. Build in buffer time or manually verify the first occurrence after each transition.

US and EU DST transitions fall on different dates. The US switches in March and November; the EU switches in late March and late October. For about two weeks twice a year, the offset between the US and UK is one hour different from normal.
Not every region observes DST. Arizona, Hawaii, most of Indiana, China, Japan, India, and many other places do not change their clocks. Assume DST applies only after you have specifically checked for the zone in question.
UTC is the only timescale that never changes. UTC has no DST offset; it advances uniformly. When in doubt about whether a time has shifted, express it in UTC and let each recipient convert to their local zone.
Set calendar invites in UTC when possible. Calendar apps like Google Calendar and Outlook store events internally in UTC and display them in local time. Creating the event directly in UTC prevents local-time interpretation errors on both sides.

Convert departure and arrival times separately. A flight that departs at 10 pm and arrives at 6 am involves two different local clock times. Convert each independently to confirm layover durations and whether you need a hotel night.
Account for flights that cross the date line. Westbound transpacific flights can arrive on a day earlier than they depart by the calendar. Check the arrival date — not just the time — when booking connections or ground transport.
Confirm hotel check-in time in local time before arriving. If your flight arrives late and check-in is at 3 pm local time, convert your arrival time to the destination zone to know whether you will need to wait or can go directly to your room.

Finding a slot that works for New York, London, and Singapore simultaneously.

Enter a candidate meeting time in your local zone.
Note the displayed times in the other participants' zones.
Look for a time when all three zones fall within working hours (roughly 8 am–6 pm).
New York + 5 hours = London; London + 8 hours = Singapore. A 9 am New York call is 2 pm London and 10 pm Singapore — the Singapore participant may prefer morning their time instead.
Adjust until all three displayed times fall within acceptable hours, then share the time in each participant's local zone.

Quickly checking what time it is right now for a colleague or contact.

Open the Timezone Converter.
Select your local city in the first zone picker.
Select the target city in the second zone picker.
The current time in the target city displays immediately alongside your local time.

Understanding what time your flight departs by your home clock.

Note the departure time and city from your ticket (e.g. 14:30 in Tokyo).
Select Tokyo in the From zone.
Select your home city in the To zone.
Enter the departure time.
The result shows the equivalent time at home — useful for telling family when to expect you.

Before calling or emailing, verify the local time at the business's location.

Select your current city in the first zone.
Select the business's city in the second zone.
The current local time at the business location displays immediately.
Compare it to typical business hours (usually 9 am – 5 pm local) to decide whether to call now or wait.

Reading server logs, API responses, or compliance records that use UTC.

Identifying the hours when team members in Asia, Europe, and the Americas are all online.

List your team's locations (e.g. Los Angeles, Berlin, Singapore).
Note the UTC offsets for each: LA = UTC−8 (or −7 DST), Berlin = UTC+1 (or +2 DST), Singapore = UTC+8.
Add those offsets to UTC business hours to find local working hours.
LA business hours (9am–5pm = UTC 17:00–01:00) overlap with Berlin (9am–5pm = UTC 08:00–16:00) from UTC 17:00–16:00 only partially. The best overlap between LA and Berlin is usually around 4–5 pm Berlin / 7–8 am LA.
Singapore overlaps better with Berlin than with LA. Schedule one call to cover the LA–Berlin overlap and a separate one for the Berlin–Singapore overlap if needed.

Confirming the current UTC offset for a specific city before sending a time-sensitive message.

Select the target city in the Timezone Converter.
The converter uses the current date, so the displayed UTC offset reflects whether DST is currently in effect.
Compare the displayed offset to the city's standard offset — if it is one hour ahead, DST is active.

Finding a time slot that falls in the evening for the US and is not too late for the UK.

A broadcast at 8 pm ET is 1 am BST (summer) or midnight GMT (winter) — too late for UK viewers.
A 5 pm ET broadcast is 10 pm BST — reasonable for UK primetime.
Use the Timezone Converter to check the UK time for each candidate US broadcast time.
Select a time where both zones fall within reasonable viewing hours (typically 7 pm–11 pm local).