Is it 'Forty'? Or 'Fourty'?

The number 40 is spelled forty despite the fact that four contains a u.

 

Even though it is often misspelled fourty, the only widely accepted spelling of the number is forty.

 Hello, everyone. We have an announcement. We are pleased/sorry to report that there is never a u in forty.

 That's right: the word for the number 4 is four, but ten times that is 40, which is spelled forty. This is true in all of the vast English language, despite rumours that users of British English like the word to resemble colour (they don't), and despite the frequent appearances of the misspelling out and about. 

In related facts, the number 14 keeps the u: it's written as 

Fourteen

But fortieth correlates to forty, so it too goes without a u.

 

*Ref. Dictionary.*