Ad vs. Add: What’s the Difference?

Here we have another set of confusing words. It’s not uncommon to see confusing words in English, so don’t get frustrated if you aren’t exactly sure when to use ad vs. add or you aren’t sure which one is correct to use and when. Both of these words sound exactly the same and they are only a single letter a part, so it’s easy to see how they can get mixed up.

In this post, I will go over the differences between these two words, their definitions, and how to use them properly in a sentence. After reading this post, you shouldn’t have any trouble at all remembering them.

When to Use Ad

what is the grammar for add or adThe word “ad” is actually a shortened colloquial form of the word “advertisement.” For example,

  • Did you see the new political ad that they are running?
  • The school took out a full-page ad in the local paper.

The first recorded use of “ad” for “advertisement” was in 1841, and, since then, “ad” has become very widespread in informal speech and writing. In formal writing, however, you should still spell out the full word “advertisement.”

  • How much is a full-page advertisement in your magazine?

When to Use Add

when should i use ad and andUnlike “ad,” which is a noun, “add” is a verb. It is defined as “to join or combine (numbers) through addition.” For example,

  • When adding odd numbers, the result will always be even.
  • If you add 6 to 7, you get 13.

It also has uses that are unrelated to joining or combining numbers but just refers to an addition. For example,

  • I will certainly add this to her list of mistakes.
  • My frequent flyer miles continue to add up with every dollar that I spend.

Add is also used in a few phrasal verbs and idioms such as “add up” and “add up to.”

  • After looking over the bill, the numbers didn’t quite add up.
  • All of the repairs added up to a pretty large repair bill.

Remember the Difference

There is a very easy way to keep track of these two words and make sure you are using them correctly in your everyday writing.

When thinking about the word “ad,” just remember the full word that it stands for “advertisement.” If you do this, there is no way that you can get it confused with add because add has two “d’s” in it, whereas ad/advertisement only has one “d” in it.

Similarly, if you remember that “add” means to constitute an addition, you won’t ever be able to confuse it with the shorter “ad.”

If you can remember these two tricks, you should be home free.


Even though these two words sounds alike and are spelled close to the same, they have wildly different meanings and it is important not to confuse add vs. ad in your writing. If you do confuse these two words, people might accuse you of having sloppy writing.

Ad is short for advertisement.

Add is a verb that refers to combining things through addition.