i.e. vs e.g.

Quick answer: i.e. vs e.g.

Use i.e. to mean "that is" or "in other words" — it restates or pins down exactly what you just said. Use e.g. to mean "for example" — it introduces one or more samples from a larger group. The fastest test: if you can swap in "that is," choose i.e.; if you can swap in "for example," choose e.g. In American English both are written with two periods and a following comma (i.e., and e.g.,); British English keeps the periods but usually drops that comma.

What the abbreviations actually stand for

Both are shortened Latin phrases, which is exactly why they get muddled — almost nobody translates them mentally.

• i.e. = Latin id est, literally "that is." It signals a restatement, definition, or precise equivalent: what follows means the same thing as what came before.
• e.g. = Latin exempli gratia, literally "for the sake of example." It introduces items drawn from a wider set: what follows is a partial list, and there could be more.

That single contrast — equivalent versus example — drives every rule below.

The one-second test

Before committing to either, read the sentence aloud and replace the abbreviation with its English meaning:

• Try "that is" or "in other words." If the sentence still holds, you want i.e.
• Try "for example" or "such as." If that fits, you want e.g.

The two are never interchangeable. If both seem to fit, the sentence is ambiguous and worth rewriting.

Correct vs incorrect examples

i.e. — restating or defining (one exact meaning):

• ✓ "The meeting is on the first day of Q3, i.e., 1 July." (1 July is precisely what "the first day of Q3" means.)
• ✓ "The book is written for bibliophiles, i.e., book lovers."
• ✗ "Bring a waterproof, i.e., a raincoat or a poncho." (A raincoat and a poncho are examples, not the sole definition — use e.g.)

e.g. — giving examples (a partial list):

• ✓ "Pack warm clothing, e.g., a fleece, gloves, and a hat."
• ✓ "Many citrus fruits, e.g., lemons and limes, are high in vitamin C."
• ✗ "The two founders, e.g., Ada and Grace, will speak." (If there are only two founders, they are the whole set, so this needs i.e.)

How one abbreviation changes the meaning

Swap i.e. for e.g. in the same sentence and you change the facts, not just the tone:

• "The senior partners (i.e., Khan and Rossi) approved it." — There are exactly two senior partners: Khan and Rossi.
• "The senior partners (e.g., Khan and Rossi) approved it." — Khan and Rossi are two examples; other senior partners exist.

That is why careful editors insist on the distinction: readers genuinely rely on it.

Punctuation: periods, commas, and italics

Keep the periods

Write both letters with a period (full stop) after each: i.e. and e.g. — not "ie" or "eg," and not "i.e" or "e.g" with a point missing. Some British publications, such as The Guardian and The Economist, deliberately drop the points as house style, but unless your own style guide says otherwise, keep them.

The comma after (the transatlantic split)

• American English: follow the abbreviation with a comma — i.e., and e.g., This is the rule in the Chicago Manual of Style and in AP style.
• British English: the comma is usually omitted — i.e. and e.g. — although adding it is not wrong.

Choose one convention and apply it consistently across a document.

What comes before

Set the whole insertion off from the main clause with a comma, a pair of parentheses, or a dash: "…on Fridays, e.g., before lunch" or "…on Fridays (e.g., before lunch)."

Don't italicise them

Although they come from Latin, i.e. and e.g. are fully naturalised in English, so set them in normal (roman) type, not italics. Italicising them is a common but needless flourish.

Tricky cases and myths

• Never add "etc." after e.g. Because e.g. already signals an incomplete list, "e.g., apples, pears, etc." says "for example" twice over. Use one device or the other, not both.
• Don't pair e.g. with "such as." They mean the same thing, so "such as, e.g., …" is redundant.
• Starting a sentence with either is awkward, not illegal. No rule forbids it, but it reads poorly — rewrite so the abbreviation sits mid-sentence, or spell out "For example."
• "They must be italic" is a myth. As above, roman type is standard in Chicago, Oxford, and AP.
• Meet the cousin, viz. Viz. (Latin videlicet, "namely") resembles i.e. but introduces a full, itemised specification. It is formal and rarely necessary; i.e. almost always does the job.
• In formal prose, consider spelling them out. Many editors keep i.e. and e.g. for parentheses, footnotes, and tables, and write "that is" or "for example" in flowing text. Both approaches are correct.

A memory trick that sticks

Two aids cover almost every case:

• e.g. = "example given." The e stands for example. It is not the literal Latin, but the matching "e" makes it easy to recall.
• i.e. = "in essence" / "in other words." The i matches, and "in other words" is exactly what i.e. does.

Or picture an egg for e.g.: an egg is one example taken from the carton, just as e.g. offers one example from many.

US vs UK: what genuinely differs

• The comma after: American English adds it (e.g.,); British English usually omits it (e.g.). This is the difference that matters most in practice.
• The points: standard on both sides, but a few British house styles print "eg" and "ie" with none. Follow your publication; otherwise keep them.
• Everything else — the meanings, the "that is / for example" test, no italics, and no trailing "etc." — is identical in American and British usage.

Frequently Asked Questions