If you have the freedom to work and live a location-independent life, dealing with multiple timezones can become an issue.

Whether this is because you have clients from around the world, your employer is within another timezone, or your own location changes frequently — overcoming the challenges of coordinating across timezones doesn’t have to be difficult.

Exhausted from making calls at 1am in the morning?

Regain control over your schedule and sleep, by following the tips presented in this article for managing your schedule across multiple timezones.

Get in The Habit of Always Stating Your Timezone

When you are working and coordinating with individuals located within a timezone other than your own, it is nearly meaningless for you to schedule a meeting at “2PM”. Instead state that you are available for a call at 2PM EST, or 11:30 London time. This especially helps to alleviate confusion, if your client is aware that you are communicating from another part of the world.

Become Familiar with a 24 Hour Clock or “Military Time”

The world largely operates by a 24 hour clock or “military time”.

In comparison to a 12 hour clock, military time removes any ambiguity from a stated hour and makes the calculation of time differences far easier.

So if don’t instantly recognize what time of day 21:15 or 21h15 is, you have some practice to do.

For example, 9 o’clock could mean 9 in the morning or the evening. But 9h00 means 9am and 9am only.

Quick! 16 hours and 15 minutes from 1am is what? …

Are you still scratching your head?

Well, what if you tried adding 16.15 to 1? Yup, that’s 17.15. Which can also be stated as 5:30pm. Can you see how much easier that is?

The quickest way to become familiar with a 24 hour clock is for you to take any digital device that you read time from, and switch it over to a 24 hour clock setting — this will only require 5 to 10 minutes. Your wristwatch, phone, laptop, microwave oven — any and everything. Nearly all digital clocks have a military time setting available.

Make these easy changes, and within two weeks, you’ll be able to read a 24 hour clock without any thought to it.

Understand GMT

GMT or Greenwich Mean Time is international time, and the basis of the world time clock. To simplify it, GMT defines the start of the day as 00:00 GMT. 5pm in London during the winter is 17:00 GMT. 5pm in Los Angeles in the winter is 17:00 GMT-8. In other words, if you add 8 hours to the local time in LA during the month of December, you’ll know what time it is in London.

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Wondering why the period of the year is important?

Countries differ in how they implement or forego the use of Daylight Savings Time. As during May, 2015, 5pm in London is 17:00 GMT+1.

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Now let’s see how the knowledge of GMT can be put to use, through a scheduling exercise with a “client” who resides within a different timezone than you.

If for example, you’ll be traveling in India during the months of June and July, you’ll know that your timezone will remain GMT+5:30. Now let’s say that you are comfortable with scheduling meetings between the hours of 6am and 11pm.

If you want to coordinate a phone call with a client located in New York (GMT-4) who is available from 8am until 6pm EST, all that is required is a little math in order to determine the ideal block of time that will suite you both. Which can be done through these three steps:

  1. Convert your local availability to military time. So 6am - 11pm now becomes 6:00 - 23:00.
  2. Calculate the absolute GMT time difference between you are your client’s time zone. New York GMT -4 becomes 4. And the sum of 4 and 5:30 (Indian GMT+5:30) equates to 9:30. This is the number of hours that you ahead of New York by, if you were in India.
  3. Convert your client’s timezone availability to your own local time, by adding the previously calculated time difference, 9:30, to your client’s time range. So 8:00 - 18:00 becomes 17:30 - 3:30*, which is 5:30pm until 3:30am. *Because a day has only 24 hours to it, if you end up with an hour beyond 24, simply subtract 24 from it to get a valid hour of day. Also, roll over any minutes beyond 60 into the next hour. E.g. 16:45 + 9:30 = 25:75 - 24 = 1:75, which is 2h15 or 2:15 AM
  4. Since you don’t want to schedule any calls at 2am, now you just need to find the overlap between your own schedule, 6:00 - 23:00 and your client’s relative time schedule of 17:30 - 3:30. Which is 17:30 - 23:00, or 5:30pm - 9pm.

Voila! You now know that you can reasonably schedule meetings, conference calls, chat, etc… between 5:30 - 9pm with your client in New York.

All that is left for you to do in order to keep sane, is to shutoff or silence your phone before you go to bed.