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Forty vs. Fourty

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2:08 min read
  Marius Alza  —  Grammar Tips
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Forty vs. Fourty

Derivation is one of the four means of word formation and probably the most important, using suffixes and prefixes to create new words. But at the same time, derivation can also become very tricky, especially when it also changes one or two letters before adding a suffix/prefix.

"Fourty" is a great example for the situation above. You may have seen the number 40 spelled both "forty" and "fourty", but does this mean that both forms are correct or officially accepted today? This situation can be very confusing, so let's clear it up quickly, shall we?

Forty vs. Fourty

With "forty", things are very clear. It is the one and only officially accepted form for the number 40 today, and is used with this sense in any context.

"Fourty", on the other hand, is the one that might create problems and confusions. This is an old form for the number 40, but it's definitely not accepted in any dictionary nowadays. Usually, if there are two forms accepted, both are mentioned in a dictionary - but it doesn't happen in the case of "forty".

When do we use "forty"?

"Forty" is the only accepted form and should always be used as the spelling for the number 40, either referring to age, quantity or numbers in general. In addition, "forty" is also the only one used in all its derivatives (forty-one, forty-two etc).

 It is true, the situation might get tricky because these numbers are formed through derivation. Six, for example, turns into "sixteen" for 16 and "sixty" for 60, by simply adding the specific suffixes after the number. This also happens for "seven", "eight" and "nine".

 "Four", anyway, is one of the numbers that make an exception. While "fourteen" follows the rule by simply adding the suffix "teen" after "four", "forty" doesn't. You won't use "fourty" in modern times, as the derivation rule would require, but delete the "u" and spell it "forty" every time.

When do we use "fourty"?

Never. The fact that this is an old form for the spelling of "forty" does not make it correct today, when no dictionary accepts it. Spelling 40 as "fourty" will be considered a mistake in any context, so we strongly advise you to never use it.


There is not much to remember about "forty" and "fourty". "Fourty" is a misspelling today, never correct, while "forty" is the only spelling for 40 existing in all dictionary. Simply take "fourty" out of your vocabulary and you will not face this confusion again.

Forty vs. Fourty

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