Converting 9 pm GMT to EST

Instructor: Deborah Schell

Deborah teaches college Accounting and has a master's degree in Educational Technology.

There are 24 time zones in the world and it's helpful to know the time if you're communicating with someone in another country. In this lesson, you will learn how to convert between GMT and EST.

Converting from GMT to EST

A time zone represents a geographic area where the time is the same. There are 24 time zones in the world. Two examples are GMT and EST. GMT, or Greenwich Mean Time, is the time at the Royal Conservatory in London, England. GMT is five hours ahead of EST, or Eastern Standard Time, which is the time zone used by cities such as New York.

If we are trying to convert from one time zone to another, we will need to consult a reference table to determine the difference between the two. For example, GMT is five hours ahead of EST, so if we're converting from GMT to EST, we will need to subtract five (5) from GMT to convert it to EST. If we are given a time in EST, we will need to add five (5) to it to convert it to GMT.

The formula is:

EST = GMT - 5

Let's use this formula to convert 9 pm GMT to EST.

EST = GMT - 5

= 9 pm - 5

= 4 pm


Therefore, when it's 9 pm GMT, it is 4 pm EST.


Let's work through a couple of examples together.

1. If it's 3 am GMT, what time is it in EST?

We know that EST is five hours behind GMT and we can use the following formula:

EST = GMT - 5

= 3 am - 5

= 10 pm

Therefore, when it's 3 am GMT, it's 10 pm EST the night before.

2. Let's try converting the other way. If it's 8 am EST, what time is it in GMT?

We know if we are given a time in EST, we need to add five to convert it to GMT.

GMT = EST + 5

= 8 am + 5

= 1 pm

Therefore, when it's 8 am EST, it is 1 pm GMT.

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