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Is it ‘21th’ or ‘21st’?

Shaun Connell
September 5, 2023

If you are trying to figure out whether '21th' or '21st' is correct, I can help!

Here is the short answer: 

  • '21th' is a grammatical error and, therefore, never correct. 
  • '21st' is the correct numerical abbreviation of the ordinal twenty-first. 
  • Twenty-first is an adjective and noun that means number 21 in a series or divisible into 21 equal parts. 

'21st' is correct, but there is much more to learn. So, stick around to read this post.

Is '21th' or '21st' Correct?

When it comes to whether '21th' or 21st' is correct, there is no gray area. '21st' is always the correct way to abbreviate the ordinal twenty-first. Ordinals are numbers in a series.

  • So, number 21 in a series of items is the '21st.'

When you are using the numeric abbreviation of an ordinal, you use the number portion followed by the last two letters in the term.

Here are some examples:

  • First - 1st
  • Second - 2nd
  • Third - 3rd
  • Fourth - 4th
  • Fifth - 5th
  • Sixth - 6th
  • Seventh - 7th
  • Eighth - 8th
  • Ninth - 9th
  • Tenth - 10th
  • Eleventh - 11th
  • Twelfth - 12th
  • Thirteenth - 13th
  • Fourteenth - 14th
  • Fifteenth - 15th
  • Sixteenth - 16th
  • Seventeenth - 17th
  • Eighteenth - 18th
  • Nineteenth - 19th
  • Twentieth - 20th

After the 20th, you use:

  • Twenty
  • Thirty
  • Forty
  • Fifty
  • Sixty
  • Seventy
  • Eighty
  • Ninety
  • One hundred

And you hyphenate the second number, for example:

  • Twenty-third - 23rd
  • Thirty-first - 31st
  • Forty-fouth - 44th
  • Fifty-second - 52nd
  • Sixty-seventh - 67th
  • Eighty-sixth - 86th
  • Ninety-ninth - 99th

When and How to Use '21st'

Now that you understand how to create numeric abbreviations for ordinals, here are some tips for when and how to use ordinals like '21st':

  • Use '21st' to reference number 21 in a series of items.

For example, you might say:

This is the 21st car that I have purchased. 

  • Use '21st' to describe the twenty-first day, year, month, or week.

For example, I might say:

Her birthday is on the 21st day of January. However, she always starts celebrating on the 15th of the month.

  • Use '21st' when you are talking about number 21 in a group of people.

So, you might say something like:

Jillian slept outside of the stadium because the first 20 people through the door would win $10,000, but she ended up being the 21st person to walk through the doors.

  • Use '21st' to refer to attempt number 21 in a series of attempts or drafts.

For example, you could say:

We have been trying to solve the problem for three years, and finally, after our '21st' attempt, we succeeded. 

Definition of '21st': What Does '21st' Mean?

According to the Merriam-Webster Dictionary, '21st' is an adjective and noun that means:

  •  Number 21 in a countable series of items, people, or days
  • One of 21 equal parts of a whole that is divisible by 21 or 1/21

Pronunciation: How to Pronounce '21st'

Pronunciation is an essential part of communication. When you know how to pronounce terms, you are more confident to use them in verbal and written communications.

So, here is a pronunciation guide you can follow:

  • Use this phonetic spelling to pronounce '21st':


Here are the pronunciations of ordinals one through twenty:

  • First - ferst
  • Second - se-kend
  • Third - therd
  • Fourth - forth
  • Fifth - fith or fif(t)th
  • Sixth - siksth
  • Seventh - se-ven(t)th
  • Eigth - ātth
  • Ninth - nin(t)th
  • Tenth - ten(t)th
  • Eleventh - i-lev-en(t)th
  • Twelfth - twelf(t)th
  • Thirteenth - ther(t)-tēn(t)th
  • Fourteenth - for-tēn(t)th
  • Fifteenth - fif-tēn(t)th
  • Sixteenth - siks-tēn(t)th
  • Seventeenth - se-ven-tēn(t)th
  • Eighteenth - āt-tēn(t)th
  • Nineteenth - nīn-tēn(t)th
  • Twentieth - twen-tē-eth
  • Thirtieth - ther-tē-eth
  • Fortieth - for-tē-eth
  • Fiftieth - fif-tē-eth
  • Sixtieth - six-tē-eth
  • Seventieth - se-ven-tē-eth
  • Eightieth - āt-tē-eth
  • Ninetieth - nin-tē-eth
  • Hundredth - hun-dredth

Sample Sentences Using '21st'

One of the most effective ways to learn how to spell a term correctly is through repetition. So, read through these sample sentences.


  • Are you coming to the event we are hosting on Monday, the 21st?
  • She interviewed more than 20 book editors, but she chose to hire the 21st person she interviewed.
  • If you are available on the 21st, I would love to take you to a party at my friend's house.
  • This is the 21st ebook she has self-published this year.
  • After she published her 21st blog post, she started seeing some SEO results.
  • They go on interesting journeys every year. This is their 21st trip to a weird destination, and they hope it will be their best.
  • Julian, a popular travel writer, was the 21st boarder to stay at the bed and breakfast that recently opened on the hill.
  • We recently moved to 21st St. downtown, and we love it. Everything is within walking distance, so we rarely have to use our car.
  • The trainer congratulated the player on his 21st win of the 2023 season.
  • Do you remember the neighborhood bar on the corner of 21st St. and Waugh Dr. that burned down years ago?
  • After completing her 21st application, she finally got a high-paying writing job that she enjoys.
  • Please turn in the first draft of your term papers by the 21st. That way, I will have enough time to grade them and get them back to you, and you can revise them in time for the deadline on the 31st.
  • We will not be able to get to work because they have 21st St. closed off for several miles.

Review of Which is Correct '21th' or '21st'

Thank you for sticking around. We covered a ton of information. So, here is a quick recap of what you learned about whether it is '21th' or '21st':

  • '21th' is a grammatical error, so you should never use it. 
  • '21st' is the correct numeric abbreviation for the ordinal twenty-first. 
  • Twenty-first is an adjective and noun that means number 21 in a series of people, places, or things. 

As a writer, you have to remember thousands of words, spellings, definitions, and grammar rules. The best writers take time to verify proper abbreviations. So, if you are unsure in the future, you can always return to this page to review this lesson.

Before you leave, read through a few of the other guides for writers. There are posts to help you find high-paying writing jobs, improve your writing, market your work, and more.

So, come back frequently to stay current on freelance writing trends and best practices. Doing so will help you become a better writer and maintain a competitive edge.

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Written By:
Shaun Connell
Shaun Connell has spent his entire career either working as a freelance writer or hiring freelance writers for his many successful publications. Shaun has learned the exact tricks of the trade to hire the perfect writer for almost any niche.

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