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How to Spell 90 and When to Use It (Examples)

When trying to spell out numbers, its acceptable to get confused. Even native English speakers find it hard to spell words sometimes.

Definition of Ninety

90 or Ninety refers to the number (numerical digit) present between 89 and 91. This cardinal number is calculated by multiplying 9 x 10.

Ninety constitutes an integral part of math. For example, in the geometry field, a 90 degree right angle is referred to often.

The number 90 gets used in other common places like percentages, articles, books, and more.

Ninety (noun) /ˈnīn(t)ē/equivalent to the product of nine and ten; ten less than one hundred; 90.

Difference Between Ninety and Ninty

One easy way to tell them apart is using the letter E; ninety has it, but ninty doesn’t.

The most significant difference between these two words is that ninty isn’t an accurate word.

Ninty is a misspelling of the word ‘Ninety.’ A common reason for the misspelling is that many other numbers don’t have an “E” letter associated with them. For example, “five” and “fifty.” Or “six” and “sixty.”

Sentence example
Sentence example

When to Use Ninety

Remember, the numerical word ‘Ninety’ means the number 90.

Sometimes, it’s better to spell out numbers rather than write them as numerals. In fact, it’s grammatically correct to spell them in their entire word form when used in common sentences.

For example, we wouldn’t want to say “90 nine numbers of things.” Because the number 90 is higher than ten, it’s suggested (by many style guides) to write it in written form rather than numerical form.

That way the sentence can read like the following, “Ninety-nine numbers of things.” Reads better, right?

Here’s an example of an incorrect sentence:

“I want to go to 90 concerts this year.”

A correct sentence would be:

“I want to go to ninety concerts this year.”

Sentence Examples

To help understand better let’s use ‘Ninety’ in various sentences. It will help you better understand what we are talking about.

They are as follows:

  • Ninety is the atomic weight of an isotope in metal strontium.
  • A full-sized baseball diamond features over ninety feet right between its bases.
  • Lilian Parker has a stunning net worth of ninety million.
  • You have about ninety-nine minutes to finish and deliver your project.
  • The malaria department witnessed a ninety percent increase in their cases as of 2022.
  • Gertrude is ninety-six years old.
  • We need someone who can bring a ninety percent increase to the sales department.
  • The lyrics go like this ‘Ninety percent skill and the power of will.’
  • I am ninety-nine percent sure that it was all just a dream.
  • You’ll be buried ninety feet deep before you ever cross me again.
  • According to a recent study, a staggering ninety-five percent of the women in this city get sexually harassed.
  • My current weight is ninety-two kilograms.

When to Use Ninty

You should always spell 90 as ‘Ninety‘ and not ‘Ninty.’

Because ninty is a misspelling of ninety.

Sentence example
Sentence example

Sentence Examples (Incorrect Sentences)

You need to understand that there are no correct sentence examples for the word ‘Ninty.’

But here are some examples of how someone can misspell it in sentences:

  • My grandmother is turning ninty years old tomorrow.
  • The country took ninty years to recover from the economic drought.
  • Is it coming up to ninty degrees?
  • The shipwreck was found ninty feet below.

Should Numbers Get Spelled Out

A good rule of thumb is that numbers smaller than ten can get used in their numerical form (1, 2, 3, 4, 5, 6, etc.). And numbers larger than 10 should get spelled out (eleven, twelve, thirteen, fourteen, etc.).

Paired number examples

  • Incorrect: 12 15-year-old students.
  • Correct: Twelve 15-year-old students.

Always spell the word out when there are paired numbers.

Decades and centuries

  • Correct: It happened in the last 1950s.
  • Correct: It happened in the fifties.

Both are acceptable ways to refer to a decade or century.

What is the Correct Spelling of the Number 90?

The correct way to spell 90 is ‘NINETY.’

Here’s a trick to remember: whenever you are trying to spell 90, ensure that you remember the spelling of the number ‘Nine’ and add a ‘Ty’ to it. Thank you! Or, nine thanks you!

Here’s another fun one: Nine drinks TEA. Or Ninety.

Sentence example
Sentence example

How to Remember Which Form to Use

Generally, always use the word “ninety” because it is a number greater than 10. Refer to the table below if you’re needing to know a certain style guides recommendations on the number.

Style GuideRecommendation
APA Style GuideWhen referring to numbers or fractions. APA style advises that common fractions (e.g.two-thirds) be expressed as words. A number of specific rules for spelling out numbers are outlined in Section 9.1 of the Chicago Manual of Style.
MLA Style GuideMLA style indicates that writers may spell out numbers if they aren’t used too frequently in the document. And can get represented with one or two words (e.g., twenty-four, one hundred, three thousand).


  1. Ninty vs Ninety: Which is the Correct Spelling of 90?
  2. Ninty vs Ninety: What’s the Difference?
  3. Ninety or Ninty: Which is Correct?
  4. How Do You Spell 90 (Ninety or Ninty)
  5. 7 Rules for Writing Numbers in APA Style
  6. Ninty vs Ninety: Common Errors in English

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About the author

Dalia Y.: Dalia is an English Major and linguistics expert with an additional degree in Psychology. Dalia has featured articles on Forbes, Inc, Fast Company, Grammarly, and many more. She covers English, ESL, and all things grammar on GrammarBrain.

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