Writing feet and inches can be confusing if you're not accustomed to it. How do you write out someone’s height when using feet and inches? Why do English speakers typically use feet and inches instead of just stating everything in inches the way Metric users state a person’s height in centimeters or in meters with a decimal? For that matter, why does anyone still use feet and inches at all?
While American Customary Units of Measurement (hereafter referred to as Imperial units for simplicity) may feel awkward to those not accustomed to them at first, the fact is that there is a solid logic behind their design and how they are used. In this article, we’ll shed some light on that through the lens of expressing common measurements such as a person’s height. Then we’ll zoom out a bit and look at why they make sense to those who use them.
Keep reading, and you'll learn exactly how to write height correctly with proper grammar.
Getting started, let’s take a look at what a couple of the most popular style guides say on the matter. While these don’t reflect informal usage, each covers a specific range of formal writing.
The two style guides below, the Chicago Style Guide and the Associated Press style guide are the most important style guides that exist. Most major publications follow one of these approaches with all of the writing and publishing. You should, too.
The Chicago Manual of Style is the standard for formal American English writing in many spheres. The correct method of writing height in Chicago style is to spell everything out exactly as it would be spoken. The logic behind this is that it will avoid any ambiguity.
The feet are specified first using feet to indicate the unit of measurement, followed by the inches indicated by the unit inches:
Note the lack of a comma between the units. It’s just a space after the feet, followed by the inches. If there are no inches left over after accounting for the feet, they are typically omitted unless absolutely required for clarity:
Another common option, especially if you want to emphasize that someone’s height is exactly a certain number of feet, is to say even in place of the inches:
The Associated Press issues its own style guide that is the standard for journalistic writing in the United States. The primary difference between the AP style and the Chicago style is that the AP style says to use digits to write the numbers:
The AP style guide also states that hyphens should not be used when writing the height of something except for when the height is being used as a description of something, such as this restated version of one of our earlier examples:
Note that when used this way foot remains in its singular form, even when there are multiple feet. When using this format, the number of inches is always included. However, the inches designator at the end is typically dropped—though if left in, it would also stay in the singular:
While the style guides referenced prefer that the units be spelled out to prevent confusion, foot/feet can be abbreviated as ft., and inch/inches can be abbreviated as in. when used in the context of measurements. Americans prefer to keep the periods at the end of the abbreviations, while British usage omits them.
In informal contexts—especially speech—it is common to drop the units altogether, such as in the following exchange:
A: “How tall are you?”
B: “I’m five-four.”
In this example, B is stating that he is five feet and four inches tall—the units are implied based on the context and a common understanding that we are using feet and inches as opposed to other units of measurement.
We touched upon this version when discussing AP style; here, we’re going to dig in just a bit further. As mentioned, this usage primarily appears when using the height as a descriptor for something else:
As discussed previously, when inches are mentioned the unit identifier is typically left off. If it is included, it stays in the singular—the same as with the feet.
In cases where there are no inches, you have a range of options in informal speech:
The last form (where you drop the inches altogether) is most typically used when talking about objects or creatures other than people.
One common way that you will see feet and inches written out is by using the prime (′) and double prime (″) notation. These markings are used in several contexts where you have a base unit (indicated by the prime symbol, which looks like an apostrophe or single quote) and a subdivision of that unit marked by a double prime symbol (which looks like a double quote).
For example, 5 feet 10 inches can be represented as 5’10” using this notation since the foot is the primary unit of length in the Imperial system—hence its prime designation. The next unit down in measuring length is the inch, so it is marked with the double prime.
This usage is especially common in diagrams (such as architectural blueprints or furniture assembly instructions). You will also see people using it in most settings where they have to write measurements down by hand, such as entering their height on a form.
Caution: As mentioned, this notation is not exclusive to feet and inches. While the context should make it clear in virtually all settings, it should be noted that another place where this notation is commonly used is recording durations. Four minutes and 15 seconds can be represented as 4’15”, in addition to such forms as 4:15 and 4m15s. Therefore, it is good to be aware of what you are looking at when you see something written out in this manner.
Sometimes you don’t know someone’s exact height. What should you do in these cases? Are there any particular social conventions that should be followed?
When you don’t know someone’s height, it is acceptable to estimate it in most contexts. Naturally, this requires some familiarity with feet and inches to be able to say. You can also buffer your statement by making a comparison against a known quantity:
While we typically do not subdivide feet into fractions, one exception to this is half feet. Where precision is either not required or obnoxious to provide, it is customary to estimate heights or lengths to the nearest foot or half foot.
The default method for indicating half units is to add “and a half” in between the number and the unit. So 5½ feet would be read as “five and a half feet.”
If there is only one whole foot, you can alternatively phrase this length as being “a foot and a half,” with the unit (a singular foot) being brought up before the and a half.
The short answer is that feet are the default unit of measurement in the Imperial system. With the exception of half-feet mentioned in the previous section, it’s not customary to subdivide feet into fractions directly—If you said that something was 5¼ feet or 5 1/3 feet you would get a strange look from people around you.
Hence, the default method is to state the number of whole feet and then express the remainder in inches:
Conversely, inches do frequently get subdivided. When talking about human heights they often get rounded to the nearest half-inch, though some people do prefer to keep it to the nearest inch all the same:
When measuring lengths in mechanical and carpentry settings, it is not uncommon to see the inch divided even smaller. For lengths over one inch, the limit is often the quarter- or eighth-inch. However, for lengths below one inch, this binary division can continue further, with some drill bit and ratchet sets going to sixteenths, thirty seconds, and even sixty-fourths of an inch. Most tape measures go down to the sixteenth-of-an-inch level. Unlike Metric units, customary usage with Imperial units strongly favors fractions over decimals in most cases.
All of that being said, while the default rule is to read measurements in feet and inches, there are times when it would be appropriate to state things as simply being a set number of inches. In particular, lengths of up to 2 feet may be expressed in inches alone:
Additionally, you’ll sometimes hear someone read the total number of inches when reading from a tape measure,
There are several reasons why Imperial measurements such as feet and inches have persisted in America and other parts of the English-speaking world, even in spite of periodic efforts over the years to migrate over to the Metric system. Let’s take a brief look at some of the most significant ones.
When you boil it down, the biggest reason why the Imperial system remains is people’s familiarity with it. While this argument will become less relevant over time as more people become fluent in both systems, the inertia this familiarity generates cannot be understated. Even in England, which switched over to the Metric system starting in 1965, the traditional units persist in at least informal usage in certain contexts (especially where human measurements and servings of alcohol are concerned), as well as in a range of idiomatic phrases and traditional proverbs:
Even setting aside common sayings. However, the fact remains that once taught basic Imperial units, they remain easy for people to picture. Being based on the length of an actual foot makes it easy for someone to use their own foot or step as a basis for estimating the length of things. Inches are similarly easy to grasp—which is more than can be said for the definition of most metric units (e.g., a meter is officially defined as “the length of the path traveled by light in a vacuum in 1/299,792,458 of a second.”). In a world where things grow increasingly cold, precise, and impersonal every day, having things of a more organic, human nature provides comfort to many people.
Lastly, Imperial units of measurement feel more human because they put comfortable levels of granularity where people look for them when living their day-to-day lives. Little exemplifies this better than measuring temperatures.
While the Celsius scale, with its basis centered around the freezing and boiling points of water, makes sense for scientific purposes, it has a range of about 40 degrees across the band where people primarily inhabit. Conversely, the Fahrenheit scale has 100 degrees at nearly the highest people in most localities experience and 0 degrees at nearly the lowest that people in most localities will experience. This places more than twice the number of degrees in the range the bulk of people inhabit, with the 100-degree cutoff falling almost exactly at the official definition of a fever for medical purposes (the Centers for Disease Control defines a fever as a body temperature of 100.4 degrees).
While base 10 is convenient for converting between different units, the increased number of factors makes the base 12 system underlying feet and inches far more convenient for division.
Ten millimeters (which are equal to a centimeter) is easily divisible by 10, 5, and 2, for example, but if you want to divide it four ways, you start having to break it down into decimals, which grow increasingly complex every time you need to divide them further (dividing it into four parts would leave you with 2.5, eight parts would be 1.25, and sixteen parts would be 0.625). Most significantly, representing division into thirds in Metric can be awkward since 10 divided by 3 results in 0.3 repeating.
On the other hand, since a foot is based around the number 12 it is easily divisible by 12, 6, 4, 3, and 2. This provides an immense amount of utility in common situations. If further subdivisions are required, the customary binary divisions of the inch mentioned earlier in this article take that into account. Division by thirds is no longer an issue because the foot itself can be divided into three equal four-inch segments. This logic is why some systems have employed a base 60 system over the years, which provides all of the divisibility benefits of 12, plus the ability to divide cleanly by 5.
There you have it. This should help you learn to write height correctly.