Home » Compound Numbers » Twenty one or Twenty-one?

Twenty one or Twenty-one?

Twenty one or twenty-one ? In this article we show you how to write 21 in English words correctly. In addition, we provide you with the grammar rule right away.

Regardless of where they appear in a number, hyphenate all compound numbers between 21 and 99 (not 30, 40, 50, 60, 70, 80, and 90) such as 21. In other words:

Hyphenate all numbers between twenty-one and ninety-nine, except those divisible by ten, even if the compound number is preceded or succeeded by numbers that do not require hyphens.

Thus, the correct spelling of 21 is twenty-one (hyphenated).

Along the same lines:

  • 21,000 = twenty-one thousand (hyphenated).
  • 21,000,000 = twenty-one million (hyphenated).
  • 21,000,000,000 = twenty-one billion (hyphenated).

Twenty-one or Twenty one Spelling

It doesn’t matter which noun follows the adjective, the grammar rule explained above remains in place. In the examples below the correct spelling is underlined.

Twenty one years or twenty-one years?
Twenty one percent or twenty-one percent?
Twenty one hours or twenty-one hours?

Frequently Asked Question about Twenty One

  • Does twenty one have a hyphen? Yes, 21 has a hyphen and is spelled correctly as twenty-one.
  • Do you hyphenate twenty one? Yes, you put a hyphen between twenty and one: twenty-one.
  • Does twenty one need a hyphen? As 21 is a compound number in between 21 and 99 it needs a hyphen; therefore writing 21 in full is twenty-one.

In the table below we show you the correct spelling of some numbers succeededing and precededing 21:


Twenty first or Twenty-first?

In the following examples the correct spelling is underlined.

Twenty first of August or twenty-first of August?
Twenty first day or twenty-first day?
Twenty first hour or twenty-first hour?

Frequently Asked Question about Twenty first

  • Does twenty first have a hyphen? Yes, the ordinal number for 21 has a hyphen and is spelled correctly as twenty-first.
  • Do you hyphenate twenty first? Yes, you put a hyphen between twenty and first: twenty-first.
  • Does twenty first need a hyphen? 21 is a compound number in between 21 and 99 which needs a hyphen. Thus, writing 21st in full is twenty-first.

Twenty first or Twenty-one?

As you already know, 21 as cardinal numeral is twenty-one, and 21 as ordinal numeral is twenty-first.

Thus, the question in the subtitle above mixes two distinguished linguistic concepts and cannot be answered as such.

Observe that you can always check how to spell a number in full correctly using our converter below.





Letter case:

Sentence case
Title Case
Spelling: Twenty-one


As explained by the hyphens-in-numbers rule, 21 = twenty-one.

If you are happy with our information, then you may also be interested in our article twenty-three or twenty three.

We love to hear your feedback and answer any question about how to correctly write 21 you might have. Use the designated form below or get in touch by email.

Kindly share this content on the social media, and don’t forget to download our app.

Thanks for visiting howdoyouspell.org.