If I want to venture into the world of typeface design, I of course would prefer to use the proper font file format. I'm wondering if there exists an industry standard for this, as well as whether there is a specific format that is particularly popular in the open source world.

My first thought is OpenType (.otf), which, I gather, supersedes TrueType (.ttf), but does it replace PostScript as well? How about Embedded OpenType (.eot)? Not sure the difference there.

I don't mean for this question to be a subjective discussion of merits and appropriateness. I'm really asking whether there is a standard, and if so, what it is, but if there isn't a standard, that should be the answer.

  • 1
    Actually, .ttf can denote either a TrueType font or an OpenType font using TrueType outlines. .otf denotes an OpenType font using PostScript outlines.
    – e100
    Commented Aug 29, 2013 at 15:50

5 Answers 5


While there are no standards, there are submissions to and recommendations from the World Wide Web Consortium.

Fonts at World Wide Web Consortium has further, more technical information. The WOFF FAQ claims that WOFF, as it gains acceptance, allows better typography, accessibility, internationalization and Search Engine Optimization.

On a related note that I hope isn't off topic, it helps to offer bold versions along with normal. Otherwise bolding is left to browsers and the end result looks shabby. Whereas when the font includes bold the result tends to look how a designer intended.


As far as I know there is no standard for free fonts. You can release it in ttf format. Other formats (such as eot, woff) are webfont formats.

  • 1
    Okay, I half-expected that. Commented Aug 28, 2013 at 12:05

I don't know about "standard", but I only purchase/download OpenType fonts (OTF) today.

I've found far too many poorly constructed TTF fonts to consider using them anymore. TTF is a fine format and there is no inherent issue with using that format. The problems I've encountered seem to be that many creators releasing TTF files are not as meticulous in the creation of the actual font file. While designers releasing OTF files seem to me more invested in the actual font file in addition to the glyph designs. Then there is the fact that OTF files can contain many, many more glyphs than TTF files.

The only time I'll use a non-OTF file is when it's demanded by a client.... and I cringe a little.

  • What exactly makes them "poorly constructed"? Is it just the smoothing/antialiasing, or lack thereof? Commented Aug 28, 2013 at 18:48
  • It isn't that TTF is inherently poorly constructed, it's that many who create TTF fonts do a poor job. I've found, in general, those creating OTF files are more concerned about font construction.
    – Scott
    Commented Aug 28, 2013 at 18:53

OpenType is the standard; it completely supersedes Postscript Type 1 and (early) TrueType formats. OTF fonts have built-in support for advanced typographical features like ligatures, stylistic alternates, etc. OTF fonts have the broadest cross-platform support (I believe) – the main computing platforms support OTF natively, both desktop and mobile as do all the major browsers.


The standard actually depends on the browser. Different browsers support different font formats, so it is best to cover all the bases and provide everything that various browsers may need. Below is the different font formats accepted by the different browsers.

  • Internet Explorer – .eot
  • Mozilla Firefox – .otf and .ttf
  • Safari and Opera – .otf, .ttf and .svg
  • Chrome – .ttf and .svg
  • Mobile Safari – .svg

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