A ligature is a character consisting of one or more connecting letters. As in the graphic above, sauerstoffflaschen—the German word for oxygen tank—is the only word to contain the “fffl” ligature. It also contains the decorative “st” ligature. Below are examples of standard and decorative ligatures.

nullligature examples
Letter pairs with their associated ligatures in Adobe Caslon Pro

When appropriate, I always use ligatures of well designed fonts for print and screen. Though, sometimes it requires a history lesson…

As many people aren’t familiar with ligatures, their use is often suspect. The use of some ligatures has become so rare that some folks view them as jarring, especially when editing or critiquing designs. Some standard ligatures—letter pairs like fi fl ff—will pass by unnoticed while others (st ct sk sti) may raise flags. Then it’s also possible, when not in edit mode/mood, some skeptics will pass over the more extravagant ligatures unnoticed.

Often, concerns with ligatures are not unfounded. Ligatures can’t be used for everything, so it’s possible to go overboard with them. They can be used in body copy above certain sizes, but rarely should they be used for titles. Letter combinations in ligatures can’t be kerned, so titles using them often suffer from blown spacing.

Posted by on December 21, 2005
Filed Under Typography | 18 Comments

  • Muffy

    I wonder how many lay-persons [non-designers, etc.] are even aware of their existence…

  • Avi Bercovich

    not very many I’m afraid… I just had an otherwise very capable office manager get back to me about the ‘funny mistakes’ in the word ‘office’.


  • Theodore Rosendorf

    > ‘funny mistakes’

    Funny indeed!
    I hope they didn’t continue to explain how to correctly spell the word office…

    I may update this post to ask how ligatures might affect legibility in text.

  • Kristopher Cargile

    Any idea as to what their original purpose was? Purely cosmetic, or something more utilitarian?

  • Theodore Rosendorf

    > Any idea as to what their original purpose was? Purely cosmetic, or
    > something more utilitarian?

    Ligatures were invented for utilitarian and cosmetic purposes. Back in the days of lead type, they were used to save space for copy fitting, and save time setting type. Ligature letter pairs (fl, fi, etc.) occur frequently in text, so you can imagine the convenience of setting one instead of two or three blocks.

    For cosmetics, ligatures are (should be) designed to support a font’s style. Below is an example of how the ‘fi’ ligature in Adobe Caslon better suits its font’s style than the clumsy f and i pair. The ligature is on the right.

    fi ligature example

  • Bhikkhu Pesala

    Should the spacing of ligatures be identical to the spacing of regular text? I have seen some bold f-ligatures (in the DejaVu Bold and Bold Italic Sans Font) that are more tightly kerned than plain text.

    That is, should:

    Difficult, and

    Di?cult always be the same width?

    I think that would be better in most cases, otherwise tracking (and hence pagination) would be affected by the use of ligatures.

  • Theodore Rosendorf

    A well designed face provides correctly spaced ligatures. Standard ligatures (fi, fl, ff, ffi, and ffl letter combinations) in roman faces accommodate the kerns of the letter (f) so the arm of the f won’t collide haphazardly, but connect elegantly with the letter following it.

    I’d say yes. And if it looks awkward—disturbing the rhythm—it’s off.

  • Bhikkhu Pesala

    I fixed the ligatures for Verajja, my version of Bitstream Vera. If the image code works you can see the results below. First plain text, then Verajja with ligatures, then DejaVu with ligatures.

    Let me know what you think.

  • Theodore Rosendorf

    Okay, I see what you mean.

    Some pairs will require more space. Some less.

    In some cases you may want to alter the letterforms to fit together as one.

    I see you’re very close.

  • Cameron

    I understand that there is a fairly common AE ligature. So therefore it should make sense to have an AF or AL ligature right?

  • Theodore Rosendorf

    The letter aesc (æ, Æ) is a ligature used in Danish, Norwegian, and Anglo-Saxon, representing the Swedish ä. In English, it represents the Greek αι (alpha iota).

    Theoretically, you could create any ligature you want and the public would judge its usefulness.

    Mrs. Eaves is a good example of a face with extra decorative ligatures.

  • Tom Flowers

    In reading old texts, I often come across the ligature AR. How does one create this ligature on the computer via unicode?

  • Bhikkhu Pesala

    Apart from the common ligatures like ff, fi, fl, and a few other Alphabetic Presentation forms, most other ligatures are not assigned a code-point in the Unicode system. You have to design them in a font editor like FontCreator or FontLab and assign them to the Private Use Area. Then, to type them you need to assign shortcut keys or create autocorrect entries.

  • Walter

    The Duden (German orthography “bible”) clearly prohibits ligatures across composition boundaries. Sauerstoffflasche has to be written with a ff and then separately fl ligature.

    Sorry, no need for a fffl-ligature, at least not in German.

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  • JC

    Firefox 3.0 and the beta version of Thunderbird (Shredder) allow display of ligatures. The ligatures accessed by looking up tables stored inside fonts.

    Firefox allows the CSS command
    text-rendering: optimizeLegibility;
    To force the browser/email reader to go pick up the ligatures and display them.

    Most of the text in the above web site is romanized Sinhala. However, if you install the special orthographic font, Sumangala at

    it turns the Latin characters into complex Sinhala letters. You MUST use Firefox to see the ‘liagaturized’ romanized Sinhala.

  • Anton Sherwood

    I’ve always wondered about the loop in the ‘ct’ and ‘st’ ligatures. It detracts from the identifiability of the components; it is not necessary to spacing. Does it have any function other than to call attention to itself? “Look at me, I’m a ligature!”

  • Joel Mielke

    I wonder how many typefaces accommodate the possible use of this word with the fffl ligature.