The Latin abbreviations "i.e." and "e.g." are often confused. When used incorrectly, they achieve the exact opposite of the writer's intention, which is to appear learned by using a Latin phrase in place of an English one that means more or less the same thing. Knowing the meanings of e.g. and i.e.—and how to use them correctly—will save you from making foolish errors and make your writing more sophisticated.

What Does E.g. Mean?

E.g. is short for the Latin exempli gratia, meaning "for the sake of example" or "for example." E.g. is used in places where you might write "including," followed by a list of one or more examples. However, e.g. should not be used to introduce an exhaustive list.

At the places where I work best, e.g., Starbucks, I have none of the distractions I have at home.

[There are lots of coffee shops I like, but Starbucks is an example that's known to most people.]

Some of the things he likes to do in his spare time, e.g., racing cars, are dangerous.

[Racing cars is dangerous, but it is not this man's only dangerous hobby.]

The abbreviation e.g. can be used with more than one example. However, avoid piling on multiple examples and adding "etc." at the end.

I like coffee shops, e.g., Starbucks and Seattle's Best, for getting work done.

[Do not write "coffee shops, e.g., Starbucks and Seattle's Best, etc."]

The children of Leda, e.g., Castor and Pollux, were born in pairs.

[Leda gave birth to multiple pairs of children, so Castor and Pollux are one example, as would be Helen and Clytemnestra. If Leda had only given birth to one pair of children, e.g. would be used incorrectly here.]

What Does I.e. Mean?

I.e. is short for the Latin id est, which means "that is to say." I.e. takes the place of the English phrases "in other words" or "that is." As opposed to e.g., i.e. is used to specify, describe, or explain something that has already been referred to in the sentence.

I'm going to the place where I work best, i.e., the coffee shop.

[There is only one place that I am claiming is best for my work. By using i.e., I am telling you that I am about to specify it.]

The most beautiful human in Greek mythology, i.e., Leda's daughter Helen, may have had a unibrow, according to a 2009 book.

[Helen, whose beauty launched the Trojan War, is considered the most beautiful woman in Greek mythology. There is no other contender, so we must use i.e.]

He wants to take some time off and go to the most relaxing place in the world, i.e., Hawaii.

[The man does not want to visit just any relaxing place. He wants to visit the most relaxing place in the world, of which there can only be one.]

When to Use E.g. and I.e.

While they are both Latin phrases, e.g. and i.e. have very different meanings, and you don't want to confuse them. E.g., meaning "for example," is used to introduce one or more possibilities or examples. I.e., meaning "that is to say," is used to specify or explain by giving more detailed information. A way to remember the difference is that e.g. opens the door to more possibilities, while i.e. reduces the possibilities to one.

I want to do something fun tonight, e.g., go for a walk, watch a movie, play a board game, read a book.

I want to do something fun tonight, i.e., watch that movie I've been waiting to see.

In the first sentence, "something fun" could be any number of activities, so e.g. is used to introduce a few of them. In the second sentence, "something fun" is one specific activity—watching that movie I've been waiting to see—so i.e. is used to specify that.

Formatting

The abbreviations i.e. and e.g. are common enough that they do not require italicization (though the full Latin phrases, if they are written out, should be italicized). Both abbreviations take periods and are followed by a comma in American English. European sources may not use the periods or the comma.

It is rare to see i.e. or e.g. at the start of a sentence. If you choose to use one of them there, you must also capitalize the initial letter of the abbreviation. Grammarians will argue over this kind of minutiae all day, so deploy these abbreviations at the head of a sentence only if you must.