Number Prefix in Font Name

Hi Everyone,

Are there any known technical issues with beginning the font name with a number? Is it likely to cause problems?

E.g. 66 Font Name

I was using Pablo Impallari’s online font tester ( and my file wouldn’t work with the numerical prefix in the file name. When i renamed it in glyphs and removed the number from the beginning of the font name and exported a new .otf the new file worked fine…

Many Thanks

Well, you found one technical issue already. The specification does not mention it: but you will have to do testing, at least in Adobe and Microsoft apps on Mac and Windows.

I used a commercial font with a number prefix last week. Can you try 66Font Name (without the space after the numbers)?

Hi Georg and Rainer, thanks for your replies

I have also tested removing the space between the numbers and the font name and it still didn’t work.

I should mention the font works fine in my adobe creative suite. I just hadn’t considered any potential issues with the naming until i tried testing it on Pablo’s online tester and discovered removing the number prefix fixed the issue.

I thought that perhaps the wider, more experienced community might be aware of an issue i am unaware of - so am reaching out

At least some web browser technology (including things like the Atom editor) don’t like a font name that starts with a number, though the specification does not technically disallow it.

thanks for your reply