Fourties or Forties: Which Spelling Is Correct?

The spelling of the number 40 and its plural form trips up writers constantly. When you need to refer to the decade of the 1940s or the age range between 40 and 49, the fourties or forties question arises. The confusion stems from the fact that the number four contains a “u,” but its multiples often do not follow the same pattern.

The correct spelling is forties—without a “u.” The word “fourties” is a misspelling that appears frequently online and in informal writing, but it has never been accepted as standard English . This comprehensive guide explains the correct spelling, explores the history behind this linguistic oddity, provides practical examples, and helps you remember the rule for good.

Quick Answer

The correct spelling is forties—no “u.” It is the plural form of forty, referring to the numbers 40 through 49, the decade of the 1940s, or the age range between 40 and 49. “Fourties” is always a misspelling. Remember: forty has no “u,” so forties has no “u” either .

Meaning Overview Table

Aspect	Meaning
Definition	The plural of forty; refers to numbers 40–49, the 1940s decade, or ages 40–49
Pronunciation	/ˈfɔːrtiz/ (FOR-teez)
Part of Speech	Noun (plural)
Usage	“She is in her forties” or “music from the forties”
Context	Everyday speech, historical writing, age descriptions, temperature ranges

Main Meaning

Definition

Forties is the plural form of the noun “forty.” It refers to the numbers from 40 through 49, the years of a decade ending in “40” (especially the 1940s), or the period of life between ages 40 and 49 . The word appears in phrases like “in her forties,” “the forties,” and “the high forties” (referring to temperature) .

Origin

The word “forty” traces back to Old English fēowertig, a compound meaning “four tens” . In Middle English, spellings like fourti and fourty appeared, reflecting the influence of “four.” However, by the end of the 18th century, the spelling “forty” had become standard, and the “u” was dropped for reasons that remain unclear . The plural “forties” followed the same pattern, appearing without the “u” in modern usage.

Context

The word appears in several distinct contexts:

• Ages: “She is in her forties” describes someone between 40 and 49 years old
• Decades: “The forties” refers to the 1940s, especially in cultural or historical discussions
• Temperature: “The temperature is in the forties” means between 40 and 49 degrees
• Streets: “The West Forties” refers to street numbers in the 40s, particularly in New York City
• Geography: “The Forties” is a region of the North Sea

Modern Usage

Today, “forties” appears constantly in journalism, literature, and everyday speech. The misspelling “fourties” remains common online, but dictionaries, style guides, and spell-checkers all flag it as incorrect . The word’s unusual spelling—lacking the “u” that appears in “four”—makes it a frequent source of error.

Detailed Explanation

Literal Meaning

Literally, “forties” means “multiple sets of forty” or “the numbers from forty to forty-nine.” It is the plural of the cardinal number forty.

Common Meaning

Commonly, people use “forties” to describe an age range or a decade. “She’s in her forties” means she is between 40 and 49 years old. “Music from the forties” means music from the 1940s.

Historical Meaning

“The forties” often refers to the 1940s, a decade marked by World War II, the beginning of the Cold War, and significant cultural shifts. Writers and historians use “the forties” as shorthand for this period.

Temperature Meaning

Weather reports and everyday conversation use “forties” to describe temperatures between 40 and 49 degrees Fahrenheit or Celsius. “It’s in the forties today” means the temperature is in that range .

Age Meaning

Describing someone as “in their forties” is a standard way to indicate age without giving an exact number. The phrase carries no negative connotation, simply indicating the fifth decade of life.

Examples Table

Example	Meaning
She is in her forties.	She is between 40 and 49 years old
The temperature is in the high forties.	The temperature is between 47 and 49 degrees
He loves music from the forties.	He enjoys music from the 1940s
The forties were a turbulent decade.	The 1940s were marked by war and change
My parents are in their forties.	My parents are between 40 and 49
The wind blew through the roaring forties.	A region of the ocean with strong winds
She celebrated her fortieth birthday.	She turned 40 years old
The office is in the West Forties.	A street address in the 40s
The forties brought significant technological change.	The 1940s saw major innovations
Temperatures will stay in the forties all week.	The weather will remain between 40 and 49 degrees

Related Meanings Table

Related Term	Meaning
Forty	The number 40; no “u” in modern spelling
Four	The number 4; contains a “u”
Fourteen	The number 14; contains a “u”
Fortieth	The ordinal form of forty; no “u”
Fourth	The ordinal form of four; contains a “u”
Forties	The plural of forty; no “u”
Fourties	A misspelling; never correct
Mid-forties	The middle of the forties range, around 44–46
Roaring Forties	A windy region of the ocean between 40 and 50 degrees latitude
The Forties	A region of the North Sea
Fortieth	The ordinal number for 40
Forty-niner	A gold prospector who went to California in 1849
Forty winks	A short nap
Forty-ounce	A large bottle of beer or malt liquor
Fortysomething	A person in their forties

Common Uses

People use “forties” across numerous contexts:

Everyday Conversation: People describe their age or others’ ages using “in their forties.” This usage is neutral and common.

Weather Reports: Meteorologists say temperatures will be “in the forties” to describe mild but cool weather.

Historical Writing: Historians and journalists refer to “the forties” when discussing the 1940s, a decade of global conflict and change.

Cultural Commentary: Music, fashion, and film from the 1940s are described as “from the forties.”

Geography: The “Roaring Forties” describes a windy belt of ocean in the Southern Hemisphere. “The Forties” also refers to a North Sea region.

Common Mistakes

Mistake	Correction
Writing “fourties”	Write “forties” (no “u”)
Writing “fourty”	Write “forty” (no “u”)
Writing “fourtieth”	Write “fortieth” (no “u”)
Assuming “fourties” is a British variant	It is not a variant; it is always a misspelling
Adding a “u” by analogy with “four”	Forty and forties are exceptions to the pattern
Writing “in her fourties”	Write “in her forties”
Writing “the fourties”	Write “the forties”
Writing “forty-four” as “fourty-four”	Write “forty-four” (no “u” in forty)
Believing the spelling changed recently	“Forty” has been standard since the 16th–18th centuries
Trusting spell-check alone	Spell-check may miss the error; learn the rule

Related Questions

Is it “fourties” or “forties”?

The correct spelling is “forties” without a “u.” “Fourties” is always a misspelling, despite appearing frequently online .

Why is “forty” spelled without a “u”?

The reason is unclear. “Four” and “fourteen” contain a “u,” but “forty” and “fortieth” do not. The spelling “forty” became standard by the 18th century, and the “u” was dropped for reasons that remain unexplained .

Is “fourties” a British spelling?

No. Both American and British English use “forties.” “Fourties” is not a recognized variant in any English-speaking region .

What does “in her forties” mean?

“In her forties” means a woman is between 40 and 49 years old. The phrase is standard and neutral.

What are the “Roaring Forties”?

The “Roaring Forties” is a region of the ocean between 40 and 50 degrees south latitude, known for strong westerly winds and rough seas.

What is “the Forties” in geography?

“The Forties” is a region of the central North Sea between Scotland and Norway, named for its depth of forty fathoms or more .

FAQs

Is it “fourties” or “forties”?

The correct spelling is “forties” without a “u.” “Fourties” is a common misspelling and is never correct .

Why do people spell it “fourties”?

People add the “u” by analogy with “four,” “fourteen,” and “fourth.” However, “forty” and “forties” are exceptions to this pattern .

What does “forties” mean?

“Forties” is the plural of forty. It refers to the numbers 40–49, the decade of the 1940s, or the age range between 40 and 49 .

Is “fourties” ever acceptable?

No. “Fourties” is always a misspelling. No dictionary or style guide accepts it as a valid variant .

How do you spell the ordinal form?

The ordinal form is “fortieth” without a “u.” “Fourtieth” is incorrect .

What is the difference between “forty” and “fourty”?

“Forty” is the correct spelling. “Fourty” is a misspelling that was common in the past but has been considered incorrect since the 18th century .

What are “the forties”?

“The forties” usually refers to the 1940s, a decade in the 20th century. It can also refer to the age range or temperature range.

How can I remember the spelling?

Remember: “forty” has no “u,” so “forties” has no “u.” Think of “forty winks” or “forty-niner”—both use the correct spelling without a “u.”

Conclusion

The fourties or forties question has a clear answer: the correct spelling is forties—no “u.” This unusual spelling reflects a historical quirk in English, where the “u” from “four” disappeared from “forty” centuries ago. While “fourties” appears frequently online and in informal writing, it is always a misspelling. Whether you are writing about someone’s age, the 1940s, or temperatures in the 40s, use “forties” with confidence. Remember the simple rule: forty has no “u,” so forties has no “u.” This small distinction separates careful writers from careless ones.