Time Zone Converter and Meeting Planner (DST-Aware)

Why time zone math goes wrong

Time zones aren't just fixed offsets. New York is 5 hours behind London most of the year, but for a few weeks each spring and fall it's 4, because the US and Europe switch daylight saving time on different dates. The US moves clocks on the second Sunday in March and the first Sunday in November. The UK and EU switch on the last Sundays of March and October. Arizona (except the Navajo Nation) and Hawaii don't switch at all. India is UTC+5:30, Nepal is UTC+5:45, and Australia's DST runs opposite to the Northern Hemisphere.

This converter doesn't use a hard-coded offset table. It asks your browser, which ships the IANA time zone database, the same data your phone and operating system use to change clocks. Pick a date in July or December and the offsets shift correctly on their own.

PST, EST, and the abbreviation trap

People say "3 PM EST" all year, but strictly EST is Eastern Standard Time (UTC-5) and only applies in winter. In summer the East Coast is on EDT (UTC-4). The same goes for PST and PDT on the West Coast. Almost everyone saying "EST" in July means "whatever time it is in New York", and this tool treats typed abbreviations that way: EST, EDT and ET all mean America/New_York with the correct offset for the date you pick.

Some abbreviations are ambiguous worldwide. IST is India, Ireland and Israel; CST is US Central, China, and Cuba. The tool maps IST to India and CST to US Central, which is what most US searchers mean. For anything else, type a city or pick a full name like Europe/Dublin from the list. When you schedule with people abroad, write the city ("3 PM New York time") rather than an abbreviation.

How to use the converter

Set the date, time, and the "from" zone. It starts as your own. Every zone in your list updates instantly with its local time, date, abbreviation and UTC offset. If the other zone has already rolled into tomorrow (or is still on yesterday), you'll see a +1 day or -1 day tag. That's the detail that ruins international calls.

Add zones by typing a city (Tokyo), an abbreviation (PST) or an IANA name (America/Sao_Paulo), or tap the quick buttons. Your list is saved in this browser for next time. Press Now to jump back to the current time.

Finding a meeting time that works for everyone

The meeting planner lays out the chosen day hour by hour in your "from" zone, with a row showing what time that is in every other zone. Teal cells are 9 AM to 5 PM local, amber cells are 7 to 9 AM or 5 to 9 PM (doable, not ideal), and plain cells are night. The bottom row marks hours where everyone is inside the workday, and the summary lists them. Click any column to set that as the meeting time.

Worked example: a team in San Francisco, New York, and London. San Francisco is 8 hours behind London, so there is no hour inside all three 9-to-5s. The closest fit is 8 AM Pacific, which is 11 AM in New York and 4 PM in London; the planner shows it amber for San Francisco and teal for everyone else. Add Bangalore and it gets worse: 8 AM Pacific is 8:30 PM in India. Then you pick who takes the amber slot, and ideally rotate it so the same people aren't always on at 10 PM.

Daylight saving edge cases

On the spring-forward night, local clocks skip an hour. In the US, 2:00 to 2:59 AM simply doesn't exist that Sunday. If you enter a skipped time, the tool tells you and shows the real time instead. On the fall-back night, 1:00 to 1:59 AM happens twice. The converter picks one of the two, so avoid scheduling anything in that hour, or say explicitly whether you mean EDT or EST.

For recurring meetings that cross the March and October-November transition weeks, check the meeting in each week of the switch. A 9 AM New York standup with London moves from 2 PM to 1 PM London time for a couple of weeks, then back.

Quick reference for US zones

Eastern (ET): UTC-5 standard, UTC-4 daylight. Central (CT): UTC-6 / UTC-5. Mountain (MT): UTC-7 / UTC-6, except Arizona, which stays at UTC-7 all year. Pacific (PT): UTC-8 / UTC-7. Alaska: UTC-9 / UTC-8. Hawaii: UTC-10 all year. So PST to EST is always +3 hours when both sides switch together, which they do. For a single time written in 24-hour format, the Military Time Converter handles the AM/PM side.