I see this sentence in a dictionary "The grass was knee-high. [=the grass reached a person's knees]"

Can we imitate that structure, for example, "you are about my chest tall" to mean the height of that person is about the height of your chest?

  • I would generally prefer "high" (as in the dictionary example) to "tall" in this situation. Oct 21, 2023 at 5:27
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    The grass was chest-high. Yes. tall or person=buzzer
    – Lambie
    Oct 21, 2023 at 16:22
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    But you are not imitating the structure: the original sentence is not "the grass was my knee high" (which is not something you can say).
    – Pilcrow
    Oct 21, 2023 at 17:11
  • Generally, if you're moving from a good sentence to one you're not sure about, it's best only to change one thing. Here, you changed "high" to "tall", and you changed the generic body part "knee" to a unique body part "my chest". Two of the answers are about "my", and one is about "tall".
    – gotube
    Oct 21, 2023 at 18:34
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    "Breast height" might be a bit more definitive: en.wikipedia.org/wiki/Diameter_at_breast_height Also, one commonly measures chest circumference at breast height.
    – Dave X
    Oct 22, 2023 at 3:53

5 Answers 5


'Knee-high' is a widely used expression, but it is mainly used to describe things - not people. For example, you can buy 'knee high socks'. You might describe flood water as being 'knee high'. Because of these many uses, 'knee high' is idiomatic in a way that 'chest high' is not. This ngram shows that 'knee-high' is found almost twice as often as 'chest high'.

Crucially though, neither are really good ways to describe the height of another person. By the time a child stands upright they are likely already taller than the height of most adults' knees, so you can appreciate why it isn't a common measure for humans. There is a humourous expression "when you were knee high to a grasshopper" which means when a person was very small, but this is pure hyperbole. If you described someone as "chest high" it would sound very odd. Whose chest? Although we measure 'height', we say a person is tall, not 'high', which makes it doubly unidiomatic. 'Chest tall' definitely doesn't sound right at all.

However, in a direct conversation with another person about their height, it wouldn't be uncommon to compare heights with a remark like "you're so tall you come up to my chest!". It would be most common in regards to a child's height - commenting on other adult's height could be considered rude in polite company.

  • She we make it clearer by saying "you're up to my chest in height"?
    – Tom
    Oct 21, 2023 at 8:18
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    Chest-high can be used of water, vegetation etc. though. Wikipedia gives "The Milky Way is overhead on November 2 2015, while chest-high ground mist rolls in to give the shot an ethereal feel." Oct 21, 2023 at 8:51
  • @tom if you're already talking about their height, it would be tacit anyway. So long as you make it clear. The height of a chest is relative. 'Chest height' would be a meaningless way to describe someone's height unless you knew whose chest they had been measured against. It's only really got any meaning if you're talking about something you experienced, like water that came up to your knee, or to your chest.
    – Astralbee
    Oct 21, 2023 at 15:50
  • @KateBunting It isn't as common, and certainly not in relation to someone's else's height - that is my point.
    – Astralbee
    Oct 21, 2023 at 15:57

You could say "The grass was chest-high" but not "my chest-high". It would be "up to my chest".

When speaking of a child's growth, say, it would be something like:

You have grown so quickly in one year. You're up to my chest.

But since "chest" covers a fairly large indefinite section of the body, "up to my chest" is unlikely in that specific context; the utterance would often use the word "here" instead and be accompanied by a gesture:

You have grown so quickly in one year. You're up to here on me! [speaker is holding their hand palm down, thumb against chest]

You have grown so quickly in one year. You're up to my chin!


No; your chest is not standard or general

As you have read, knee-high is a common expression used both metaphorically for people (I've known him since he was knee-high to a grasshopper) and literally for things (my grandfather always said the corn should be knee-high by the 4th of July). However, this is a 'standard' or 'collective' knee-high, not the specific height of my knees, nor those of any other single person.

'The wheat was chest-high in the field' would be an acceptable expression as well, and again refers to some universal, if vague, standard height.

What is 'wrong' about 'you are my chest tall' is that my chest is not a standard against which things can be measured, so there is no "my chest tall" as a concept. Rather, I should compare the person to my chest; the person has primacy. "You are as tall as my chest", "you are chest-high to me," and "you come up to my chest" are all valid expressions, but I would not compare a person against an implied standard of my own chest.

  • There's en.wikipedia.org/wiki/Diameter_at_breast_height
    – Dave X
    Oct 22, 2023 at 3:57
  • @DaveX There is - but it is not DmBH (Diameter at my breast height), because my breast height is not a standard. Rather, as the article you cite says, "In the United States, DBH is typically measured at 4.5 ft (1.37 m) above ground."
    – Kirt
    Oct 22, 2023 at 4:41

In British English, "chest height" is how this would be described idiomatically - for example "the child who was running around was chest height". Note that this doesn't necessarily mean that the child is exactly at your chest height - rather that on an "average" person the child would come up to their chest. If you want to be specific about your chest height, then you'd say so explicitly - "the child came up to my chest".

As an aside, the only other parts of the body which this is idiomatic for (at least in non-colloquial contexts) are the ankles, knees, waist and neck - for example "the dog was waist height". In particular "head height" isn't idiomatic and "as tall as me" or "up to my head" would be used.

For a particularly casual British usage, if you want to indicate the height of something using your hand, you can say "it was yay high" with your hand around the height of the object you're describing.


No, you cannot say "you are about my chest tall" because the word "tall" doesn't work the way "high" does.

"High" can be pre-modified with just about any noun that indicates a consistent height:

three apples high
my chest high (grammatically correct, but really unnatural)

"Tall", on the other hand, is not so versatile. It can naturally be pre-modified with a unit of measurement or a deictic determiner:

180 cm tall
this/that tall

"Chest" cannot pre-modify "tall".

A further issue is you changed the premodifier from a general height "knee" to the height of one specific thing "my chest". This isn't even natural with "high", let alone "tall".

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