Frequently Asked Questions
What is a stencil font?
A stencil font is one designed for laser cutting or physical stencils. Enclosed areas (like the hole in "O" or "a") would fall out without support. Bridges are thin connections that hold these islands in place. They show as small breaks in the letters: the familiar stencil look.
How do bridges work?
The algorithm detects which glyphs have enclosed white areas. For each area, it cuts a small gap (bridge) through the surrounding stroke: out to the open space around the letter, or into a neighbouring area that already has a way out, as the lower half of a B does. In most letters the cut follows the letter's own inner and outer edges exactly, and every curve it doesn't touch is kept as the designer drew it. When laser-cut, the bridge holds the enclosed piece in place so it doesn't fall out. Hairline areas thinner than 1% of the font size are usually filled in instead of bridged.
Will this work with my font?
Most valid .ttf and .otf fonts work, and the engine places bridges even on complex glyphs like é and @. In fonts that draw letters from overlapping pieces (common in script and variable fonts), some letters can lose part of their shape where the pieces overlap, and an Ø whose slash is drawn over an O can keep an enclosed area. Fonts with unusual designs can need touching up in a font editor, so always check the result, and test-cut a sample before cutting anything valuable.
What file formats do you accept?
.ttf (TrueType) and .otf (OpenType) fonts. You normally get the same format back: a .ttf stays a .ttf, and an .otf stays an .otf, though an .otf built with TrueType outlines comes back as a .ttf. Variable .ttf fonts are converted in their default style, as a regular (static) font. Variable .otf fonts aren't supported yet.
What happens to my font?
Nothing: it never leaves your device. The stencil engine runs inside your browser, so your font is read, bridged and saved on your own computer or phone, and is never uploaded to us or anyone else. See our Privacy Policy for full details.
Am I allowed to convert my font?
Only if you made it, its licence allows you to modify it, or its owner has given you permission. Adding bridges changes the font, so it makes a modified version. Many free fonts allow that: the SIL Open Font License and the Apache License both do, with conditions. Many paid fonts don't, even when they allow commercial use, so check the licence (often called an EULA) before you convert. Fonts that came with Windows, macOS or other software usually don't allow it either. You're asked to confirm this each time. See our Terms of Use.
Can I use the output commercially?
The stencil version is still covered by the original font's licence. We don't change the licence or give you any extra rights, so you can use and share it only in the ways that licence allows for a modified copy. This isn't legal advice: if you're unsure, read the licence or ask the font's maker.
Why do I have to choose a new name?
Some fonts under the SIL Open Font License reserve their name: a modified copy must be called something else, however small the change. When a font does this, we ask you for a new name and check it doesn't use the reserved one. Other fonts get “Stencil” added to their name.
Why won't it convert some fonts?
Fonts carry a setting in which their maker can say they must not be modified without permission (“restricted licence”). We respect it and don't convert those fonts. Variable .otf fonts also aren't supported yet.