Is fourty ever correct?

No. Modern standard English accepts only forty. Fourty appears in older manuscripts and in present-day typos, but no current dictionary lists it as a variant.

Why does fourteen keep the u when forty drops it?

Because the vowel was shortened only in the decade compound. In fourteen the first syllable kept its full length, so the spelling kept the u; in forty the shortened vowel came to be written without it.

Twenty. English once counted in scores — four score is eighty — and the word survives in fixed phrases like four score and seven years ago.

Why are there sixty seconds in a minute?

Because Babylonian astronomers counted in base-60, and Greek and medieval scholars kept their convention. The sixty-fold division passed into clocks and into the 360 degrees of the circle.

1decade name that drops the u of its root — forty alone

-tysuffix meaning a group of ten, from Old English -tig

4×20how French still says eighty: quatre-vingts

40forty

A ledger of number names

Forty Number Names

English writes forty without the u that four keeps — the only decade name that breaks from its root. This record explains how that spelling settled, how number names are assembled from tens and hundreds, and what older ways of counting left inside the words.

fortyon.com
Ledger entry no. 40 — tens, dozens, scores
A reference ledger of number names, from forty's missing u to the score and the dozen.

Twenty to ninety, in order

The decade index

40fortyThe only English decade name that drops the u of its root word four.

80quatre-vingtsFrench names eighty as four twenties, a living trace of base-20 counting.

60sixty secondsBabylonian base-60 survives in the minute, the second and the degree.

Forty in seven languages

The word for forty in seven languages, and how each is built
Language	Word for forty	How the word is built
English	forty	four plus the ten-suffix -ty, with the u dropped
German	vierzig	vier (four) plus -zig, fully regular
Dutch	veertig	vier plus -tig, regular, close to the German pattern
French	quarante	from Latin quadraginta; the link to four is historical
Spanish	cuarenta	from Latin quadraginta, like French
Danish	fyrre	short for fyrretyve, four tens — yet Danish counts 50 to 90 in twenties
Welsh (traditional)	deugain	two twenties: base-20 counting, still in living use

The word for forty in seven languages, and how each is built

Why is it forty and not fourty?

Because the vowel of four was shortened inside an old compound, and the spelling settled without the u long before dictionaries fixed English spelling.

Old English wrote the number as fēowertig: fēower, the ancestor of four, joined to -tig, a suffix meaning a group of ten. Inside the compound the first syllable was pronounced shorter than the standalone word, and short vowels in English have a long habit of being written with fewer letters.

Through the Middle English period scribes wrote the word as they heard it, and they heard it differently: fourty, fourtie, fortie and forty all appear in manuscripts. The forms without u tracked the shortened pronunciation, and they multiplied as the vowel of the first syllable weakened.

When printing reached England in the late fifteenth century, variants began to narrow, and the shorter spelling steadily won. By the time Samuel Johnson's dictionary entered the word as forty in 1755, the u-less form was the standard, and fourty survived only as an error — which is its status in every major dictionary today.

Terms used in this record

Numeral: A word or symbol that names a number. Forty and 40 are both numerals for the same value — one a word, one a digit string.
Cardinal number: A number that answers how many: one, forty, a hundred. Its counterpart is the ordinal, which answers which in order: first, fortieth.
Base (radix): The number at which a counting system starts a new level. Base-10 starts a new level at ten; base-20 at twenty; base-60 at sixty.
Vigesimal: Counting in twenties. French quatre-vingts, the old English score and traditional Welsh deugain are all vigesimal forms.
Duodecimal: Counting in twelves. The dozen, the gross and the twelve-inch foot are duodecimal survivals in a decimal world.
Positional notation: A way of writing numbers where a digit's value depends on its place, as the 4 in 40 means four tens. It requires a zero to hold empty places.

Common questions about forty and number names

Is fourty ever correct?: No. Modern standard English accepts only forty. Fourty appears in older manuscripts and in present-day typos, but no current dictionary lists it as a variant.
Why does fourteen keep the u when forty drops it?: Because the vowel was shortened only in the decade compound. In fourteen the first syllable kept its full length, so the spelling kept the u; in forty the shortened vowel came to be written without it.
What is a score?: Twenty. English once counted in scores — four score is eighty — and the word survives in fixed phrases like four score and seven years ago.
Why are there sixty seconds in a minute?: Because Babylonian astronomers counted in base-60, and Greek and medieval scholars kept their convention. The sixty-fold division passed into clocks and into the 360 degrees of the circle.

How this record was made

This record was assembled from standard dictionaries, grammars of English and comparative works on numeral systems. Historical dates are given as broad periods because spelling change is gradual. No material from any previous site at this address was used or available.

Sources and further reading

The reading list points to standard etymological dictionaries, histories of English spelling and comparative studies of numeral systems.