Fourty or forty?

The word fourty is not a real word, but it is a common misspelling. The word forty is the correct spelling of the number 40.

Your writing, at its best

Compose bold, clear, mistake-free, writing with Grammarly's AI-powered writing assistant

What is the difference between fourty and forty?

When it comes to spelling numbers, one of the most common mistakes we see involves the number 40. You know–– the amount that’s ten more than 30 and ten less than 50? We are happy to say that no matter the topic, the correct modern spelling of 40 is forty, not fourty. Period. 

It’s forty, not fourty

The English Language spells the number 4 as ‘four,’ 14 as ‘fourteen,’ but 40 as ‘forty.’ Seems confusing, right? To clarify, here’s a quick breakdown of how to write numbers containing the number four: 

  • 4: four
  • 14: fourteen 
  • 40: forty
  • 44: forty-one 
  • 42: forty-two
  • 43: forty-three
  • 44: forty-four 
  • 45: forty-five 
  • 46: forty-six
  • 47: forty-seven
  • 48: forty-eight
  • 49: forty-nine
  • 400: four hundred
  • 440: four hundred and forty 
  • 4,000: four thousand
  • 4,000,000: four million 

We think you get the picture. 

When did fourty become forty?

Outside of numerical spelling differences, English writers also grapple with spelling changes over time. For instance, if you lived between the 12th and 15th centuries, you wouldn’t be wrong to use ‘fourty’ instead of ‘forty.’ 

As far as we can tell, the current spelling forty accompanied other spelling variants during the 16th century, such as ‘fourtie,’ ‘fortie,’ or ‘vorty.’ But even before Modern English, the number’s spelling was a mess. 

Fourthy,’ ‘forti,’ ‘fourty,’ and ‘feowrti’ are just four out of 18 different spellings that occurred at the time, and among these Middle English variants came the spelling of ‘forty,’ which became the primary Modern English spelling by the 18th century. 

Whether this change occurred from a historical pronunciation change or “standardized” English, the facts remain unclear. But we can say one thing with absolute certainty: forty vs. fourty has nothing to do with American English vs. British English. And for that, we can be thankful. 

What does forty mean?

The word forty is a cardinal number ‘equal to 4 X 10’ (40), or it involves other numbers between forty to forty-nine (40-49). English speakers use the word forty as an adjective or noun to describe anything quantifiable–– whether it’s age, speed, garment size, etc. 

For example, 

“The Google domain costs forty dollars.” 
“She is a forty-year-old woman.” 
“He wears size forty-two.”

Additional meanings of ‘forty’

The plural form of forty is “forties,” which might imply an era of one’s life or the historical period of the 1940s’. For example, 

“I can’t wait until my forties.” 
“Polaroid cameras opened a new world of photography in the nineteen-forties.” 

According to Lexico, “the Forties” also represents the central North Sea between Scotland and southern Norway, as the sea depth supposedly begins at forty fathoms. 

“Father’s oil ship is passing through the Forties.” 

We can also use the word “fortieth” (40th) to describe 40 consecutive events or intervals, while the word “fortyish” implies a range of numbers near the amount of forty. For example, 

“Today is our fortieth wedding anniversary.” 
“There are about fortyish people at the event.” 

Lastly, the word “fortyfold” is an adjective and adverb that describes ‘forty times as big or as much.’ For example, 

“Within the first decade of settlement, New York’s population expanded fortyfold.” 


Quadfragenarian, quadragesimal. 

Etymology of forty

The Middle English adjective forty entered the English Language via Old English fēowertig and Northumbrian feuortig. Old English fēowertig means “40” and consists of fēower for ‘four’ and -tiggroup of tīen (10).’ 

English phrases of forty

The word forty carries several connotations outside of the classic number. In the United States, people use numbers 40-49 to reference U.S. presidents, gun calibers, or simply “forty” to mean a ‘40 oz. bottle of beer or malt liquor.’ 

Americans also use phrases like forty winks(circa 1821) to mean ‘a brief nap,’ or “forty-niner” to describe participants of California’s 1849 gold rush. Speaking of which, have you heard of the San Francisco 49ers? As it turns out, the name of the city’s football team commemorates the region’s unique history. 

Of course, we’d be remiss to forget the “lower forty-eight,” an Alaskan phrase that references all US states below the region of Alaska. Who knew? 

How to use the word forty for AP and Chicago style?

Learning how to use forty is straight-forward, but writing style rules can affect how we use numbers in sentences correctly. Two of the more common writing guides include the Associated Press Stylebook or The Chicago Manual of Style, which both provide different rules for in-text numbers. 

In general, the AP Stylebook spells out cardinal numbers between 1-9 (except decimals), while Chicago writes out cardinal numbers between 0-100. 

For example, 

AP Style: “My favorite number is 40” or, “I write for 40 minutes a day.”
Chicago Style: “My favorite number is forty” or, “I write for forty minutes a day.”  

However, if you’re using a number to describe time, quantity, age, or distance, there’s a good chance these guides provide specific stipulations on using forty or 40 in a sentence. 

Let’s compare the AP Stylebook and Chicago’s suggestions for forty vs. 40:


AP: “The 40th century.”
Chicago: “The fortieth century.”


AP: “The 1940s.” 
Chicago: “The 1940’s,” “The ‘40s,” or “The forties” (as long as the century is known).


AP:She is in her 40s” or “She is 40-years-old.” 
Chicago:She is in her forties” or “She is 40-years-old.” 

40 million, billion, or trillion nouns vs. dollars

AP:40-million Grammarly users” or “$40 billion.”   
Chicago:Forty million Grammarly users” or “$40 billion.” 


AP:40 feet by 20 feet.”
Chicago: “Forty-by-twenty feet.”  


AP:40 miles away.” 
Chicago:Forty miles away.”


Chicago:40 percent” or “40%” (use symbol for technical writing). 

The AP Stylebook and Chicago’s shared rules for 40 vs. forty

  • Spell out numbers at the beginning of sentences.
  • Use figures for ages (e.g., “40-years-old). 
  • Use figures for monetary amounts with symbols (e.g., $40). 

Of course, The Chicago Manual of Style and AP Stylebook contain several other guidelines for numerics, but our general outline can help you get started in the right direction. 

Want to know more?

If you’d like to learn about other tricky words within AP and Chicago formats, check out The Word Counter’s recent posts, such as: 

Test Yourself!

Test how well you understand the difference between forty vs. fourty with the following multiple-choice questions. 

  1. The proper spelling of 40 is ___________.
    a. Forty
    b. Fourty
    c. Feowrti
    d. Fourti
  2. True or false: “fourty” is an older form of “forty.”
    a. True
    b. False
  3. The use of fourty fell out of favor by the ____________.
    a. 16th century
    b. 17th century
    c. 18th century
    d. 19th century
  4. Which is correct for AP and Chicago?: “She tweets ________ a day
    a. 40 times
    b. Forty times
    c. 40-times
    d. None of the above
  5. Which of the following amounts contains an incorrect spelling of 40? 
    a. Forty dollars
    b. Four-hundred and thirty-five dollars
    c. Fourty dollars and fourteen cents
    d. Four-thousand and forty dollars


  1. A
  2. A
  3. C
  4. D
  5. D


  1. Forty.” The American Heritage Dictionary of the English Language, 5th ed., Houghton Mifflin Harcourt Publishing Company, 2020. 
  2. Forty.” Cambridge Dictionary, Cambridge University Press, 2020.
  3. Forty.” Lexico, Oxford University Press, 2020.
  4. Forty.” The Dictionary, Merriam-Webster Inc., 2020.
  5. Forty.” Oxford English Dictionary Online, Oxford University Press, 2020. 
  6. Forty winks.” Cambridge Dictionary, Cambridge University Press, 2020.
  7. Harper, Douglas. “Forty.” The Online Etymology Dictionary, 2020. 
  8. Numbers.” The Chicago Manual of Style Online, 16th ed., The University of Chicago, 2010. 
  9. Numerals.” AP Stylebook, The Associated Press Stylebook, 2020.