The 10-Second Answer
Use i.e. when you mean “that is” or “in other words.” Use e.g. when you mean “for example.” The easiest memory trick is this: think of i.e. as “in essence” and e.g. as “example given.” One explains exactly; the other offers possibilities.
Why Are These Tiny Abbreviations So Confusing?
English has no shortage of word pairs waiting to trip us up. We wrestle with “affect” versus “effect”, pause over “which” versus “that”, and occasionally stare at i.e. and e.g. as though one of them might confess first.
They look similar. They are both short. They both appear before additional information. To make matters worse, they come from Latin—because apparently ordinary confusion was not enough.
Fortunately, the difference between them is simple:
- i.e. introduces a clarification or exact restatement.
- e.g. introduces one or more examples.
That is the entire rule. Once you understand what each abbreviation is doing, choosing the right one becomes much easier.
What Does “I.e.” Mean?
I.e. comes from the Latin phrase id est, meaning “that is.” It introduces information that defines, restates, or clarifies what came immediately before it.
Think of it as a tiny sign saying:
“Here is exactly what I mean.”
For example:
The meeting will take place at our main office (i.e., the building on Oak Street).
The phrase after i.e. identifies the exact office. It is not suggesting one possible location among several. “The building on Oak Street” is what “our main office” means in this sentence.
Here is another example:
My favorite meal of the day (i.e., breakfast) should never be rushed.
The writer is not listing breakfast as one possible favorite. Breakfast is the favorite meal being discussed.
You can test both sentences by replacing i.e. with “that is”:
The meeting will take place at our main office—that is, the building on Oak Street.
My favorite meal of the day—that is, breakfast—should never be rushed.
The meaning remains intact, so i.e. is correct.
What Does “E.g.” Mean?
E.g. comes from the Latin phrase exempli gratia, which means “for example” or, more literally, “for the sake of example.”
It introduces one or more members of a larger group. The examples help illustrate the point, but they do not represent every possibility.
Think of e.g. as a sign saying:
“Here are a few possibilities.”
For example:
Bring something to read on the flight (e.g., a novel, magazine, or comic book).
Those are suggestions, not the complete list of everything a passenger could read. A biography, newspaper, or cereal box would also qualify.
Another example:
Some animals are active at night (e.g., bats, owls, and raccoons).
The sentence does not claim that bats, owls, and raccoons are the only nocturnal animals. They are simply examples.
Replace e.g. with “for example,” and the sentence still works:
Some animals are active at night—for example, bats, owls, and raccoons.
That tells you e.g. is the right choice.
For a dictionary-backed overview, Merriam-Webster’s explanation of i.e. and e.g. uses the same practical distinction: one restates, while the other supplies examples.
The Simple Trick You Will Actually Remember
The Latin origins are useful, but you do not need to become fluent in Latin to write a decent email. Instead, remember these unofficial phrases:
- I.e. = in essence
- E.g. = example given
These are not the phrases the abbreviations truly stand for, but they are effective memory aids.
The first letters do the work:
- The I in i.e. reminds you that you are explaining the idea in other words.
- The E in e.g. reminds you that you are giving an example.
When in doubt, use the replacement test:
- Substitute “that is” or “in other words.”
- If that works, choose i.e.
- If it does not, substitute “for example.”
- If that works, choose e.g.
This test is more reliable than simply choosing whichever abbreviation looks better. As with many grammar questions, you cannot always trust your ear to identify the correct form.
One Pair of Sentences That Shows the Whole Difference
Consider these two sentences:
I am visiting one European capital this summer (i.e., Rome).
I would like to visit a European capital this summer (e.g., Rome).
In the first sentence, Rome is the definite destination. The abbreviation i.e. clarifies exactly which capital the writer will visit.
In the second sentence, Rome is one possible destination. The writer might visit Rome, Paris, Lisbon, or somewhere else. The abbreviation e.g. merely supplies an example.
That difference can affect real meaning. Imagine receiving these two instructions:
Please bring identification (i.e., your passport).
This means the requested identification is specifically your passport.
Please bring identification (e.g., your passport).
This means a passport is one acceptable option, but another form of identification may also be allowed.
Two letters, two periods, and a surprisingly important distinction.
How to Punctuate “I.e.” and “E.g.”
In American English, both abbreviations are commonly written in lowercase with periods:
- i.e.
- e.g.
They are also usually followed by a comma:
We need a warm destination (i.e., somewhere without snow).
Pack warm clothing (e.g., a coat, gloves, and a scarf).
Placing the abbreviation and its related information inside parentheses is often the cleanest option. The MLA Style Center’s guidance on e.g. and i.e. recommends using the abbreviations within parentheses and spelling out “for example” or “that is” outside them.
Different publications may follow different house styles, so professionally edited work should follow the required style guide. For everyday writing, this pattern will serve you well:
General statement (i.e. or e.g., additional information)
Do not italicize the abbreviations in normal use. The complete Latin phrases may be italicized when discussed as Latin terms, but the familiar abbreviations are generally treated as ordinary parts of English.
Common Mistakes to Avoid
Using “i.e.” for a Partial List
Incorrect:
I enjoy outdoor activities (i.e., hiking and kayaking).
This says hiking and kayaking are the writer’s complete definition of “outdoor activities.” If they are merely two activities among many, use e.g.:
I enjoy outdoor activities (e.g., hiking and kayaking).
Using “e.g.” Before an Exact Restatement
Incorrect:
The package will arrive on the final weekday (e.g., Friday).
If Friday is definitely the final weekday being referenced, use i.e.:
The package will arrive on the final weekday (i.e., Friday).
Adding “Etc.” After “E.g.”
Avoid this:
We sell baking supplies (e.g., flour, sugar, baking powder, etc.).
Because e.g. already signals that the list contains examples rather than every possible item, etc. is unnecessary. The Chicago Manual of Style’s explanation specifically advises against combining the two.
Write:
We sell baking supplies (e.g., flour, sugar, and baking powder).
Beginning a Sentence With the Abbreviation
Technically, an abbreviation can be capitalized at the beginning of a sentence, but the result often looks awkward:
E.g., you could take the train.
The smoother choice is:
For example, you could take the train.
Clarity beats abbreviation acrobatics.
Should You Use the Abbreviations at All?
Sometimes the best way to avoid mixing up i.e. and e.g. is to spell out what you mean.
In emails, articles, instructions, and other writing intended for a broad audience, “that is,” “in other words,” and “for example” may be easier to read. Not everyone knows the abbreviations, and some readers will pause to mentally translate them.
Compare:
Several citrus fruits (e.g., oranges and lemons) contain citric acid.
Several citrus fruits, such as oranges and lemons, contain citric acid.
Both are correct. The second may feel more conversational.
Use i.e. and e.g. when they make a sentence more compact without making it less clear. If you suspect your reader might hesitate, spell out the English phrase. Good writing is not about fitting the most Latin into the smallest space.
Test Yourself
Choose i.e. or e.g. for each sentence:
- Please use a permanent writing tool (___, a pen).
- We serve several hot drinks (___, tea, coffee, and cocoa).
- The twins share a birthday (___, April 12).
- Try adding a fresh herb (___, basil or parsley).
- The event has been postponed until the following day (___, Thursday).
Answers:
- i.e. — A pen is the exact writing tool intended.
- e.g. — The drinks are examples from a larger selection.
- i.e. — April 12 is the twins’ specific birthday.
- e.g. — Basil and parsley are possible herbs.
- i.e. — Thursday is the exact day meant.
The Final Rule
If the information after the abbreviation tells the reader exactly what you mean, use i.e.
If it gives the reader one or more possible examples, use e.g.
Or, in its shortest form:
I.e. explains. E.g. exemplifies.
Remember “in essence” and “example given,” perform the replacement test, and these two little abbreviations will never ambush your writing again.