Use i.e. when you mean “that is” or “in other words” and use e.g. when you mean “for example.”

Quick rule

  • i.e. = restate or clarify the previous idea.
  • e.g. = give one or more examples, not a complete list.

Easy test

Replace the abbreviation in your sentence:

  • If “that is” works, use i.e..
  • If “for example” works, use e.g..

Examples

  • “Bring a warm layer, e.g. , a jacket or sweater.”
  • “I prefer citrus fruits, i.e. , oranges and lemons.”

Writing tip

You can often avoid both and just write “for example” or “that is” if you want the sentence to feel clearer.

TL;DR: i.e. clarifies; e.g. gives examples.