I am new to creating/editing fonts. I want to create a font with custom symbol for "glyph not found". I have downloaded FontForge as it seems to be a widespread free font editing program. I was hoping first U+0000 NUL, Default Character would be that, but it seems that I was wrong. I cannot find any info on how to make your own "glyph not found" symbol on google, maybe here somebody could help?

  • 1
    U+0000 is a defined character and not an un-defined one, so no, that will not work. .notdef is a unique glyph on its own and does not have a Unicode assignment. That would defeat its purpose. See typedrawers.com/discussion/comment/35074#Comment_35074 (you may want to read the entire thread).
    – Jongware
    Jul 5, 2018 at 9:03

2 Answers 2


The "glyph not found" glyph (most commonly drawn as a box, often with an X or a question mark inside of it) should be named .notdef and it should be glyph 0 in your font. This glyph doesn't normally have a Unicode codepoint.

I believe most font editors will put your .notdef glyph into position 0 when generating your font binaries, so long as it's named correctly and does not have a Unicode codepoint.

Source: Glyph 0: the .notdef glyph from Microsoft's Recommendations for OpenType Fonts

  • Welcome to GDSE!
    – curious
    Aug 9, 2021 at 1:46

So far as I'm aware there is no “glyph not found” character. Different programs use different graphic presentations. An empty narrow rectangle is a common rendering, but not the only one. It could also be a rectangle with a question mark in it or with the code number of the character, in hexadecimal, in it.

From the Unicode Spec:

The Unicode glossary entry says:

It often is shown as an open or black rectangle.

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