I'm trying to write "3 and a half year old," as in, "He is a 3 and a half year old dog".

I know a hyphen or two is supposed to go in there somewhere. Per Ways to write "2000 year old" , I suspect it should be "3-and-a-half-year-old", but that reads like death-by-hyphen, even if it is correct.

What's the proper way to hyphenate "# and a half year old" in this context?

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    Covered under english.stackexchange.com/questions/152041/… – Leon Conrad Feb 14 '14 at 19:31
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    I would certainly write three-and-a-half-year-old dog as such. Yes, it’s five hyphens in a row, but it doesn’t seem unnatural to me, really, because the hyphens are all logical and balanced. – Janus Bahs Jacquet Feb 14 '14 at 19:35
  • @LeonConrad - Duplicate noted; voting to close as duplicate. – JoshDM Feb 14 '14 at 19:35
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    Certainly. Numbers up to and including ten (or, according to some, twenty) are usually spelt out, particularly when they occur as natural parts of a sentence, as the number here does. I would say, for example, “The size of the box is 3 x 4 x 6 inches” (because they appear here as more mathematical units), but “It was a small box, only about three by four by six inches in size” (because the numbers are more naturalised into the sentence and less rigorously numeric in their ‘appearance’, as it were). – Janus Bahs Jacquet Feb 14 '14 at 19:39
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    Following up on Janus Bahs Jacquet, you could also simplify your life by using just numbers, as in "The dog is 3½ years old." – rhetorician Feb 14 '14 at 21:06

I recommend first that you use either "three-and-a-half-year-old" or "3½-year-old," and that you not mix spelled-out numbers and numerical numbers as in "3-and-a-half-year-old" and "three-and-½-year-old."

Another common (but in my view unjustifiable) form of punctuation in unedited manuscripts is, for example, "three-and-a-half-year old," where the author omits the final hyphen as though old were a stand-alone noun in the context of the given age.

The other obvious option is to leave the words open: "three and a half year old." This approach avoids what you consider the hyphen plague of "three-and-a-half-year-old," but it also de-emphasizes the unitary aspect of the phrase, which the heavily punctuated form makes clear.

You might also think of the form "three-and-a-half-year-old" as offering a recognizable-at-a-glance contrast to the similar phrase "three-and-a-half years old," where years is indeed a freestanding noun.

In any event, if five hyphens in a stretch of six words strikes you as too many, you have two practical options that don't do violence to the words' interconnectedness:

  1. Use "3½-year-old" instead of "three-and-a-half-year-old." (You are within your rights to do this unless your publisher/style guide insists that you spell out all numbers below a certain minimum. In this regard, an anonymous editor has added this helpful note to my answer: "Note for those using APA formatting: Numbers one through ten are always spelled out." I'm not familiar with APA style, but such variations in preference are not at all unusual.)

  2. Recast the sentence so that you can describe the person or thing as being "three-and-a-half years old" rather than "three-and-a-half-year-old."

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  • I would not put any hyphens at all in ‘three and a half years old’. Apart from that, +1. – Janus Bahs Jacquet Feb 14 '14 at 21:03
  • Not a fan of the "½" character. Oh look, it didn't even conform to how you typed it in the answer. – JoshDM Feb 14 '14 at 22:38

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