I'm working on a project that has a a convoluted acronym with an O in it. In addition to being difficult to remember, it's very easy to mistake the O for a zero since it's not a word and it already has a number in it. (Example: F4TYO -- a reader who has never encountered this and doesn't know what it stands for may think that O is a 0)

Since I don't have control over the name, I want to try using a font that will make the O look very much like an O and not a zero.

Most fonts I've seen seem to focus on making the zero distinct (e.g. a slash, a dot, or boxy curves). I'm looking for a font where O is really distinct instead and very clearly an O and not a zero, even if it's mixed in with numbers.

I need to use a free font (Google fonts are OK). Suggests for non-free fonts would be welcome too though as they may lead me to ideas that point me in the right direction. Other ideas for designing around this problem would be welcome.

Edit: Another way to phrase this question as Sebastian mentions in the comments is "How would one even differentiate an O from a 0 in the absence of the latter"

  • This seems pretty broad, given it could be any font with a distinct 0 and O pair. What other restraints do you have for the font? Commented Jun 15, 2017 at 13:55
  • 1
    Do you have any other style constraints? For example a calligraphic font might do this but would look out of place in a lot of technical projects.
    – Chris H
    Commented Jun 16, 2017 at 8:03
  • 2
    @ChrisH No, there aren't other clear restrictions, per say. The audience for this project is scientific researchers. Commented Jun 16, 2017 at 16:31
  • 1
    @Scribblemacher The following chat message might be of interest to you: chat.stackexchange.com/transcript/message/38225583#38225583
    – user61223
    Commented Jun 19, 2017 at 19:35
  • 1
    To add context to the previous comment: Chuck Bigelow is one of the foremost type designers of the last several decades (e.g. he with Kris Holmes created the Lucida family of typefaces, also Monaco, etc), and he has recently (2013) written a wonderful 14-page article called Oh, oh, zero! about exactly this issue: distinguishing the letter O from the numeral 0. Commented Jun 20, 2017 at 0:09

8 Answers 8


Some visual clues that will tell your users the O is a letter:

  1. If the O has thicker sides than the top and bottom.
  2. If the 4 is an old-style numeral that sits below the baseline.
  3. If the O is much wider than the number 4.

One free font I found that has all 3 is Goudy Bookletter 1911:


If that font looks too old-fashioned or unprofessional, you can either render some characters in one font and some in another, or you can pick a font that uses only 2 of the 3 clues, such as Actor.

  • 2
    A better font that satisfies all 3 is in Baldrickk's answer: French Canon.
    – NH.
    Commented Jun 15, 2017 at 19:52
  • 2
    My real project has a 3 in it, not a 4 (I didn't use the real name in my question), but your points are still applicable. I personally like the old fashioned look of Goudy. Using different typefaces and/or styles for different characters within the word is another good idea, although that's an appropriate I can only really use in a logo/header Commented Jun 16, 2017 at 12:00

My suggestion would be to make the number distinct from the letters instead of worrying about the O itself; maybe a different colour or size.

Thereby implying that anything else is a letter.


Assuming this is meant for use as a logo, where you have a bit more leeway in tools at your disposal, I'd suggest focusing on contrast between the number character and the letter characters. This could include:

  • different fonts (ie. Helvetica v. Bodoni)
  • different colors
  • different scale
  • different weights (ie. light v. bold)
  • different styles (ie. italics v. book)
  • etc.

Or any combination of the above.

Quick examples. The top is using different fonts and the bottom different colors: enter image description here

The goal here is to make the 'O' clearly belong to the rest of the letters in the word leaving the actual number the odd-one out.

  • I've tried a few approaches so far and haven't finished my designs yet, but most of the approaches I'm trying are using the idea presented here, to make the number look different rather than focusing on the O. Commented Jun 22, 2017 at 13:52

As @Sebastian rightly rephrased, "How would one even differentiate an O from a 0 in the absence of the latter? I don't think there's a convention for that."

You are asking for ideas to get around your problem. I propose that you work it out via the width of the characters: You have got F4TYO, i.e. four letters and one digit. So search for fonts where the digits (numbers) are obviously more narrow than the (capital) letters. That way the 4 is indirectly telling your readers that the O is not a 0 but a capital letter. If you cannot find much distinction in width, my second choice would be stroke-width (but any quality font would hardly have a noticable difference between letters and digits).

I need to get going, so will not do your homework. Once you have decided what you are looking for, I am confident that you will find a suitable font with that feature. Since style of digits is not normally tagged, you will probably need to look through many examples on your typeface-provider of preference, sorry. Please write an update and let us know how you solved it finally.

Since this intruiged me, I took time for one example, there must be better but I only serched for a few minutes:

enter image description here

So, seeing only the O will not tell much, but next to the 4, I believe that it feels owie.

(And I hate it when other users do it to my questions, but I just cannot resist for this question: "What you want is bad." - At least it is not your fault; but even the fact that you are having this problem means that the acronym sucks altogether. Normally customers should be able to figure out what it means - and then the question would not even post itself. So if they cannot know what it means, maybe it is less important whether that is a digit or a letter (and nobody will want to pronounce it anyway). My condolences, and please take this last paragraph not too seriously.)

  • 4
    I actually thank you for the last paragraph. I'm still holding out hope that I can convince the powers that it should be changed. If it's difficult to pronounce and remember, I think an acronym isn't working correctly. Commented Jun 16, 2017 at 12:06
  • Yes, I have been yelled-at on this forum, where my humour had created misunderstandings. I have respect for your for trying to raise to this challenge and solve it at the technical level. But then also trying to get to the root of the problem: the bad and lame acronym (BALAC). So I am glad that you understood my humour and my hidden encouragement. Still courious how you will decide (with those powers) in the end. Good weekend. Commented Jun 16, 2017 at 18:02

There are some fonts that use "old style figures", and so have a displacement between the positioning of uppercase alpha and numeric characters, e.g. IM FELL French Canon Font

enter image description here

Personally, I don't like this much, and I prefer Digital's answer.


I don't think there's really any unambiguous and widely established way to indicate that "this is a capital letter O, not a zero." The closest I can think of is that, in most fonts, all numbers tend to have the same width (so that they'll line up nicely), and thus a zero tends to be narrower than it's tall (unless it's a lowercase zero, that is).

So you could look for a font where the letter O is much wider than other letters, maybe even a perfect geometric circle. Such perfectly circular O's are often found e.g. in "geometric sans" fonts inspired by the art deco and Bauhaus design styles of the early 20th century, of which the most well known one nowadays is probably Futura. For example, here's your example text "F4TYO" rendered in URW Futura No 2 D Book:

Futura No 2 D Book

and in Monotype Century Gothic Std Regular:

Century Gothic Std Regular

You could further emphasize the roundness of the O by picking a font where most other letters are particularly narrow. For example, here's the same text in ITC Plaza Std:

Plaza Std

and Mecanorma Organda MN:

Organda MN

Unfortunately I can't recommend any good free alternatives off the top of my head, although I'm sure they exist. However, if this is just for a single logotype, you could always just take any reasonably geometric looking free sans-serif font that you like, and redraw the O yourself. After all, a perfect circle is among the simplest possible shapes to draw.

  • 4
    To me, in the last 2 examples the "O" is so different (at ~4x the width of the other letters) that it's no longer an "O" but a circle. (And the kerning on Century Gothic between the "Y" and the "O" looks like the "O" is making a bid for freedom, but that could presumably be fixed). +1 for the concept,
    – Chris H
    Commented Jun 16, 2017 at 7:57

(Since you're looking for a font, this doesn't directly answer your question, but this suggestion is too long for a comment. =) )

Perhaps there are some alternative approaches that you could use:

  • Use lowercase letters. f4tyo. Clearly the last character is a lowercase o and not a zero. Based on current website naming trends, apparently there are some people who think that using all-lowercase names is hip or cool. Acronyms do not necessarily need to be in all-uppercase (e.g. people usually do not capitalize scuba, laser, or radar in modern usage). Note that doing so might introduce ambiguity between 1 (one) and l (lowercase L), but perhaps you could selectively use lowercase only for some letters.

  • Use diacritics. F4TYÖ. Who cares if the diacritical mark is meaningless there? Heavy metal bands didn't care. Or use an accent mark (F4YTÓ) and pronounce it with, say, a Spanish accent.

  • 4
    As someone who uses 'Ö' in daily writing I would like to discourage its use when you actually mean 'O'. People familiar with it will read and retype it as a completely separate letter. Of all diacritics I would probably be okay with a macron for this use: 'Ō'. But then others might be confused by that.
    – Emil
    Commented Jun 16, 2017 at 7:14
  • 2
    I'm open to the lower-case idea. In fact, I came to a similar conclusion shortly after I posted this question. I'm still debating whether such an informal style will work for this particular project, but it's definitely a viable option. Commented Jun 16, 2017 at 11:50
  • 3
    I want to +1 the lowercase idea as quite creative and one obvious solution. And then yell at you and -1 for abusing the Ö and calling its dots meaningless. That is as if I would ask you to use a stroke through your lower-case l (as in lame idea) to distinguish it from an upper case I (as in India), because "for me" the horizontal stroke through an l is rather meaningless. And bad luck, if it looks to millions of people like a t (as in teaser)... So that gets you +1 -1 = 0. Maybe kill the second part of the idea or make it a separate answer, then I will gladly like the lowercase idea. Commented Jun 16, 2017 at 18:11
  • I want to ... but I am not. When re-reading it sounds too harsh, but was written with a grin. Too late to edit, 5 minutes have passed. Language is emotional, and as each language has got its little weirdnesses, some of us care especially about those. Commented Jun 16, 2017 at 18:22
  • 1
    The lowercase suggestion won't really help if the acronym is written in a font using OSF, of course—an OSF zero will just look like a lowercase oh instead of an uppercase one… Commented Jun 17, 2017 at 16:12

We've had a couple of examples with a circular "O", but so far no suggestion of a rather square "O". To me this stands out quite clearly. The example here is Fetamont (based on the metafont logo)

fetamont sample

One rather clichéd way to make numbers stand out is subscript (pseudo-chemistry) or superscript. This may or may not work in your context. The former would look something like F₄TYO.

  • When I read your reasoning, I thought "well, because it'll look like a monospaced zero," but the O in Fetamont actually does look very much like an O (I think due to its width). Commented Jun 16, 2017 at 11:36
  • 1
    @Scribblemacher yes, I really did mean "square" rather than rectangular. In this particular font the typical capitals are very similar in width to each other and about 25% wider than the numerals. Of course there are alternatives, but the downside to Fetamont is it's a small-caps font.
    – Chris H
    Commented Jun 16, 2017 at 12:32
  • Given the target audience (scientists) I'd probably avoid the chemistry-style subscript I suggested - some find such abuse of notation irritating.
    – Chris H
    Commented Jun 16, 2017 at 16:46
  • 2
    Yes! You found a good example for my idea above: A font with distinctly wider letter than numbers. I had a hunch that it would exist - because almost anything has been tried in typefaces. Just harder to find a certain tree these days in such a wonderful jungle (sorry, forrest). Commented Jun 16, 2017 at 18:14

Not the answer you're looking for? Browse other questions tagged or ask your own question.