How to Schedule Meetings Across Time Zones Without Doing the Math

I work from Mumbai, and a lot of the people I work with are in the US and Europe. For years I scheduled calls by doing the math in my head. "London is four and a half hours behind, New York is another five, so..." And I got it wrong more times than I'd like to admit.

So here's the process I use now. It's simple, and it has stopped me from showing up an hour early (or late) to calls.

1. Start with the overlap, not the time

Most people pick a time that works for them and then check if it works for everyone else. That's backwards.

Write down everyone's working hours in their own time, then find the window where they overlap. For India and the US East Coast, that window is tiny: roughly 6:30 PM to 9:30 PM in India, which is 9 AM to noon in New York. For India and the UK it's much easier, because most of the UK workday overlaps with an Indian afternoon or evening.

If there's no overlap at all, someone has to stretch. Decide who that is, and rotate it if the meeting repeats. It's not fair for the same person to always take the 11 PM call.

2. Pick one anchor city

When you're juggling three or four cities, choose one as the anchor and say every time in that city's time first. Teams with people everywhere often use UTC because it never changes for daylight saving.

The important part is that everyone knows which clock you're talking about. "Let's do 3" means nothing on a remote team.

3. Watch out for daylight saving weeks

This is the trap that gets almost everyone. Countries don't change their clocks on the same day, and many (including India) don't change them at all.

• Europe moves its clocks back on the last Sunday of October. This year that's October 25.
• The US moves back on the first Sunday of November. This year that's November 1.

So for one week, from October 25 to November 1, London and New York are only four hours apart instead of five. Every recurring meeting between them moves by an hour for one side, and calendars don't always make that obvious.

From India it's even messier, because we don't change at all. Right now London is 4.5 hours behind IST. After October 25 it's 5.5 hours. If your weekly call with London is at 3 PM your time, it will suddenly be at 9:30 AM their time instead of 10:30 AM.

The same thing happens in March, when Europe and the US move their clocks forward on different Sundays.

4. Remember half-hour time zones exist

India is UTC+5:30. Nepal is UTC+5:45. Parts of Australia and Canada have half-hour offsets too. Lots of mental math assumes whole hours, and that's where the "wait, is it 4 or 4:30?" moments come from.

5. Send the time in their time zone

When you propose a time, write it in the other person's time zone, or in both. "Does 10 AM your time (7:30 PM mine) work?" is much easier to say yes to than making someone convert it themselves.

And always send a calendar invite. Calendars store the time properly and show it in each person's local time, which gets rid of most mistakes.

The tool I made for this

After getting it wrong enough times, I built Time Zone Pro, a world clock for iPhone, iPad and Mac. You add your cities, drag one 24-hour slider, and every clock moves together. So you can see what 4 PM in London means in New York, Dubai and Mumbai at the same time, with day and night indicators that make it obvious when someone is asleep.

It handles daylight saving and half-hour offsets for you, which covers points 3 and 4 above. It's free on the App Store.

But even if you never use it, the process above will save you from most time zone mistakes. Find the overlap, pick an anchor, watch the daylight saving weeks and say the time in their time zone.