I'm in the UK, which uses metric units for pretty much everything now except road distances and beer (obviously best kept apart).

Page sizes have been metric here and in most of the rest of the world for many years.

Can anyone suggest any reasons why printed type is still always measured in points, e.g 11pt (= 11/72 inch) rather than say millimetres?

In counterpoint, does anyone use anything else?

Edit: Obviously points have worked fine for centuries. But there would seem to be significant advantages measuring type in the same metric units as you measure the page it's placed on, especially if setting up a grid.

Edit: Wikipedia has a page on metric typographic units, and there's a bit more context on use in Germany and Japan on the main typographic unit page.

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    I think your question is a bit unclear here, you probably mean points per inch, not points in your question... In any case, this question is argumentitive, doesn't contribute to the conversation, and should probably be closed. Jan 5, 2011 at 15:30
  • I don't closing is that clear cut anymore ...Maybe have a look at blog.stackoverflow.com/2010/09/good-subjective-bad-subjective
    – phwd
    Jan 5, 2011 at 15:41
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    I've toned it down a bit and clarified I'm talking about printed type - but I'm genuinely interested in any good reasons (e.g. I suspect Quark only supported points as the unit for type sizes)
    – e100
    Jan 5, 2011 at 15:52
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    I think one should ask: why NOT points? What does metric or inches give us that points does not? How is the specification of paper size in any way related to how I measure or speak about type sizes?
    – horatio
    May 11, 2011 at 14:30
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    note that points don't measure the height of the type, but the height of the 'virtual space' the type takes up. So, not an terribly literal measurement to begin with.
    – DA01
    May 11, 2011 at 16:05

4 Answers 4


The most basic reason points are still around is there's nothing metric that can usefully replace them. Note that word, "usefully." There are a couple of reasons why: (1) as Lauren points out (pun hard to avoid... or resist), 6-12-72 has many more even divisors than decimal, so it's easier to work with, just as 60 is much more practical for angles and time than any kind of decimal equivalent. But (2) in very practical terms, 1/72nd of an inch is a much smaller increment than 1 mm. A 1mm difference in type size is much greater, visually, than a 1 point difference. 10 point type and 11 point type are markedly different sizes, but 6 mm and 7 mm are enormously different. The eye sees incredibly fine differences in typography. One word out of alignment by as little as 1/10th of a point is visible even to the untrained eye, and leaps out at a designer like DayGlo socks at a funeral. So if we tried to shoehorn our type sizes into a decimal strait-jacket, we'd be working with unwieldy fractions all the time.

The no-longer-relevant-in-the-digital-age measurements, like ciceros and agates, are endangered species, hanging on only in protected corners of InDesign and Quark, no longer seen in the wild. Points, like cockroaches, are hardy survivors that will be here long after mankind has rendered himself obsolete.

Like most systems of measurement, points are fundamentally arbitrary, but they have stuck around for centuries because they are so immensely practical. The relatively coarse metric system just isn't a good substitute. For much the same reason, you're not likely to see grams replace carats in the gem industry, either. And for a slightly different reason, the good old British pint will be with us for a long time to come.

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    As a minor critique, computer design renders all units of measurement completely interchangable (provided the programmer obliges). Also, you are giving special status to points in your argument: 1/10th of a point is allowed, but a micrometers aren't?
    – horatio
    May 11, 2011 at 14:26
  • Computer design indeed renders units interchangeable. People are less flexible, though. 1 point is .013888... inches. That's bad enough, but it's 352.77777... micrometers. If someone proposed sizing type in 350 um increments, my wild guess is there would be no takers. When something is extremely workable and widely familiar, there are very few reasons to change it. None of them are good reasons. Your average Brit, for example, will give up his pint the day they pull it out of his cold, dead hands... :-) May 11, 2011 at 19:41
  • Personally I would suggest a new unit, the Font unit, 100 font units = 72 points the old way. I have a feeling there aren't any takers here either :-)
    – user7179
    Dec 4, 2012 at 20:45
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    Basing units on 12 is so much easier than 10 that I still don't understand how metric made it. 10 can be evenly divided into halves and fifths. 12 has halves, thirds, quarters, and sixths. As Alan describes, type greatly benefits from this finer divisibility. Dec 4, 2012 at 23:02

I can't cite anything in particular, but from my U.S. perspective, the 6-12-72 base is very flexible (that is, it's easy to divide and get round numbers), and since we've been measuring and defining type this way for 150+ years, the industry is unlikely to make a wholesale change on its own. Inertia is pretty powerful.

To change points to mm, you'd wind up getting all sorts of repeating decimals, or we'd have to redefine absolutely everything, which might mean a lot of very tiny type retooling. And re-purchasing.

I have to say I've never even heard of type, itself, being measured in anything else (other than pixels, which is not for print).

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    Good points - why would you need to re-purchase though?
    – e100
    Jan 5, 2011 at 17:18
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    I'm assuming that foundries would use "New! Metric fonts!" as an excuse to re-issue type "which is correctly proportioned to metric measurements" or some other such blather. I don't think type really comes in just 10 pt, 12pt, 36 pt etc. any more, but any which does would definitely have to be re-sized for 30m, 33mm, etc. so you'd know what you were choosing in your program's type palette. Jan 5, 2011 at 17:53
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    Nice pun e100 :P May 11, 2011 at 23:07

Every standard dimension has its unit of measurement

Type has been around since Gutenberg and it's always been set in points. Every dimension has it's own unit of measurement. Let's say we have metres. Why would anyone use AUs in space measurements? Why not use kilometres instead? The same goes to type. Why use mm if points are units of type size.

If you'd read The elements of typographic style you'd see that particular point sizes related to type have their own names as well (like nonpareil: 6pt, minion: 7pt, brevier, bourgeois etc...). It's been standard for hundreds of years, why invent something unconventional and confuse the world.

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    Take your points (pun intended), but an AU appears to be based on a fundamental measure which can't easily be expressed in SI units, whereas a modern point is a relatively simple fraction of an inch. Yes, I've read the book. But those fixed sizes date from an era where metal typefaces were available in common fixed sixes, rather than having the ability to be arbitrarily scaled.
    – e100
    Jan 12, 2011 at 14:27
  • @e100: As you stated yourself: fractions... Isn't it better to express something in whole numbers than fractions? Isn't it better to say 10mm than 0.01m? Jan 12, 2011 at 18:04
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    If one is trying to match the layout of text which was set in a 10pt font with 3pt leading, is it really easier to describe it the spacing as as a 4.586mm than 13pt? Note that if places a 65-line column 4.6mm spacing next to one with 11pt spacing, they'll be off by 0.76mm at the bottom--very noticeable. Even 4.59mm spacing would be off by about 0.21mm--still noticeable.
    – supercat
    Jun 17, 2014 at 17:32

The only explanation that I can offer is bureaucratic inertia. "This is the way that we've always done it, and if it was good enough for Grandpa..."

The only programs that I've found (at a price that a college student can afford) that allow you to specify sizes in millimeters are the Adobe CS2 programs that were accidentally released into the wild, and an older version of Ragtime known as Ragtime Solo.

I would LOVE for current mainstream publishing programs to allow type to be specified in millimeters (like the German DIN 165702 standard), but since Adobe, Quark, et al are headquartered in one of the three companies in the world that have not adopted the metric system, I don't see it happening anytime soon.

  • InDesign (and presumably other CC software) allows entering type sizes in mm. There is even a Preference toggle for that. Bin so since CS6 or the first CC, so for at least 5 years.
    – Jongware
    Oct 25, 2018 at 22:38

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