'e.g.' and 'i.e.':the difference

The abbreviations 'e.g.' (from Latin 'exempli gratia') and 'i.e.' (from Latin 'id est') are often confused. This is because they are both used to introduce some clarification of something previously mentioned.

+ 'e.g.'
The abbreviation 'e.g.' is used to provide an example:
"The buffet provided excellent variety, e.g., vegetarian and non-vegetarian soups, Italian and French breads and numerous sweets."
(e.g. = for example)

"He was the school champion of many activities (e.g., chess, badminton and 110m hurdles)."
(e.g. = for example)


+ 'i.e.'
The abbreviation 'i.e.' is used to restate an idea more clearly or offer more information.

Examples:
"It happened in August; i.e. two months ago."
(i.e. = in other words)

WRONG: "It happened in August; e.g. two months ago."
(e.g. = for example)

"Service charge is included in all prices, i.e., you don't have to leave a tip."
(i.e. = in other words)


+ Getting Them Wrong:
Often mixing the abbreviations up does not mean your sentence is grammatically incorrect. However, getting them wrong will change the meaning of your sentence.

Examples:
"All amphibians are thriving in the new pond; e.g., the two bullfrogs were being very active yesterday."
(This sentence is fine grammatically. From it, we infer that there are more amphibians than two bullfrogs in the pond.)

"All amphibians are thriving in the new pond; i.e., the two bullfrogs were being very active yesterday."
(This sentence is fine grammatically. We infer that the only amphibians in the pond are the two bullfrogs.)


+ HOT TIPS - REMEMBERING WHICH IS WHICH:
This may assist in remembering:

e.g. = "example given"
i.e. = "in effect"

THE FORMAT WITH E.G. OR I.E.:
- Comma before is okay:
"He directs a variety of genres, e.g., crime, disaster, drama,
fantasy."
- Semicolon before is okay:
"He directs a variety of genres; e.g., crime, disaster, drama,
fantasy."
- Brackets are okay:
"He directs a variety of genres (e.g., crime, disaster, drama,
fantasy)."
- Starting a sentence is okay:
"He directs a variety of genres. E.g., he directs crime, disaster, drama and fantasy."

COMMA AFTER E.G. OR I.E.:
In the US, it is usual to follow 'e.g.' or [/i]'i.e.'[/i] with a comma. It is less common in the UK. There is leniency in all conventions. The golden rule is: be consistent.

FULL STOPS (or PERIODS ) OR NOT:
It is usual to see full stops (or periods) with 'e.g.' and 'i.e.' However, you can write them without. The golden rule is simply: be consistent.


+ WARNING - DON'T USE ETC. AFTER E.G.:
The examples you offer after using 'e.g.' are usually samples from a more complete list. Therefore, it is often not appropriate to use 'etc.' after 'e.g.' since it is understood that you are only offering a partial list by way of example. In the example below, the 'etc.' is redundant:

"Mark needs gloves to handle live fishing bait (e.g., rag worm, lug worm, crab, etc.)"
In the example above:
the use of e.g. is correct.
the use of etc. is wrong.

http://www.grammar-monster.com/easily_confused/eg_ie.htm