# “6-foot tall” or “6-feet tall”?

I have heard/seen people say/write "She is 5 feet 10 inches tall" and "She is 5-foot-10." But in formal writing, is there a convention? I found both "8-foot-tall" and "nine-feet tall" in online sources.

The bronze, 8-foot-tall LBJ sculpture is slated to be installed at downtown's Little Tranquility Park, bound by Capitol, Walker, Bagby and Smith streets. (source)

Nine-feet tall and bronze, the monument to the famous novelist has been erected in the grassy center of the 13.7-acre park's circular drive. (source)

• This is a good question, but you should note that "Nine-feet tall" is a typo in the original source. It should just be "Nine feet tall", with no hyphen. – stangdon Aug 17 '18 at 17:41
• – ColleenV Aug 17 '18 at 18:44
• – user3395 Aug 17 '18 at 19:00

When a measurement is used right before the noun it measures, use a hyphen and the singular form of the unit of measurement:

I saw a 95-foot yacht in the harbor.
The 12-mile climb is too arduous for casual visitors.
The monument is in the 13.7-acre park's circular drive.

A dimension can also be included with another hyphen:

I saw a 95-foot-long yacht in the harbor.
The 8-foot-tall sculpture is impressive.
The flagpole is a 25-foot-tall, 3-inch-thick bamboo pipe.

However, when the measurement is used as a predicate, separate from the noun it measures, use the plural form of the unit of measurement. Don't use a hyphen:

The yacht I saw was 95 feet long.
The flagpole is 25 feet tall and 3 inches thick.
I can only finish a climb that's 4 miles or less.
Nine feet tall and bronze, the monument is popular among tourists.
She is 5 feet 10 inches tall.

In the first example, the adjective '8 foot tall' comes directly before the noun it modifies, while in the second example the adjective 'nine feet tall' is part of its own phrase. The two forms of the adjective would sound out of place if they were in each other's positions in the sentence.

The second form (8 feet tall) would also be the best form to use with the verb 'to be'.

The statue is 8 feet tall.

The singular form 'foot' can more readily be substituted for the plural 'feet' than 'feet' can be substituted for 'foot', but it is not a standard usage to do so. It sounds colloquial.

My wife is five foot tall.