What a FIGlet banner is and how this generator builds one
FIGlet is the program that has been turning short words into large letters made of smaller characters since the early nineties, the banners you still see at the top of README files, in terminal startup messages, and printed by command line tools when they launch. Each font is a plain text file describing every character as a small grid of pipes, underscores, slashes and parentheses, and the program stitches those grids together side by side to spell out whatever you typed.
This page runs the same idea in your browser. Type into the text field and the banner is regenerated on every keystroke, using the FIGlet library and the font file for whichever font is selected. In the Standard font the word HI comes out five rows tall, with the H drawn as two vertical pipes joined by an underscore crossbar and the I as a bracketed column, so the whole banner is around eleven characters wide for two letters. That ratio is worth keeping in mind: a FIGlet banner is typically six to eight columns wide per letter, which is why short words work and sentences do not.
Nothing is sent anywhere. The font files are part of this site and the rendering happens in the page, so the text you type stays in the tab.
The twenty two fonts and how to choose between them
The font menu offers twenty two of the classic FIGlet fonts rather than the full collection of several hundred that ships with the original program. They are Standard, Big, Slant, Shadow, Small, Mini, Block, Banner3, Bubble, Digital, Doom, Ghost, Graffiti, Isometric1, Larry 3D, Lean, Ogre, Speed, Star Wars, 3-D, Alligator, and Colossal. Each one is loaded on demand the first time you select it and then kept for the rest of the session, which is why switching to a font you have not used yet shows a brief loading state and switching back to one you have used is instant.
Standard is the safe default and the one most people recognise. Small and Mini are the compact options, useful when the banner has to fit somewhere narrow. Big, Block, Colossal, and Banner3 are the heavy ones, roughly twice the height of Standard, which suits a project title at the top of a README. Slant, Lean, and Speed lean the letters to the right for a sense of motion. Shadow, Doom, Ghost, and Graffiti are decorative, and Star Wars and Alligator are stylised enough that legibility drops away for anything longer than a single short word.
Isometric1, 3-D, and Larry 3D deserve a warning. They draw each letter in pseudo perspective, which means they are both very tall and very wide, often more than a dozen columns per character. They look striking with three or four letters and become an unreadable wall with eight.
Making a banner fit the width it has to live in
The practical constraint on an ASCII banner is almost always horizontal. A terminal is conventionally eighty columns, a GitHub README renders code blocks at a similar width before it starts scrolling sideways, and a source file often has a line length limit set by a formatter. Since Standard uses roughly seven columns per letter, eighty columns is about eleven characters of text, and a heavy font such as Colossal will run out of room at six or seven.
There is no automatic wrapping. If the banner is too wide it simply keeps going, and whatever displays it will either wrap the lines at arbitrary points, which destroys the shapes, or scroll sideways. The fix is to shorten the text or change the font. A project called continuous-deployment becomes a banner nobody can read in any font here; the same project rendered as CD in Colossal, or as deploy in Small, works at once. Splitting a two word name across two separate banners stacked vertically is another common approach, generating each word on its own and pasting them one after the other.
Check the result at the width it will actually be seen at, not in the preview box on this page. A banner that looks fine in a wide browser window can break the moment it lands in a terminal.
Pasting the result into code, READMEs, and terminals
The copy button puts the whole banner, newlines and internal spaces intact, on your clipboard. Because it is ordinary text it can go anywhere plain text goes, but three details decide whether it survives. It must be displayed in a monospace font, since the alignment depends on every character occupying the same width and a proportional font shifts the columns out of true. It must keep its line breaks. And nothing in the destination may trim trailing whitespace, because some fonts rely on trailing spaces to keep the last column of a letter in position.
In a README, wrap the banner in a fenced code block so the markdown renderer uses a monospace font and does not reflow the lines. In source code, use a block comment rather than a run of single line comments, since a formatter that reindents comment bodies can shift rows relative to each other. For a terminal banner, a heredoc or a text file printed with cat is more reliable than an echo with escapes, which tends to mangle the backslashes that many of these fonts use for diagonal strokes.
If the copied banner looks fine in one place and broken in another, the destination is almost always the cause rather than the generator. Pasting the same text into a code editor is a quick way to confirm the banner itself is intact.
Which characters render and which do not
FIGlet fonts define glyphs for printable ASCII: the upper and lower case letters, the digits, and common punctuation such as the hyphen, underscore, full stop, and exclamation point. Anything outside that range has no glyph to draw. Accented Latin letters, Cyrillic, Greek, CJK characters, and emoji will not render as banner art, so a name with a diacritic needs the plain ASCII spelling instead.
Case is preserved and does matter. Most of these fonts were designed with capitals in mind and look more solid in upper case, while lower case letters in the decorative fonts are often noticeably shorter than their capitals, leaving an uneven top edge. Spaces work and separate words as you would expect, though a space costs the same several columns as a letter, so a two word banner is close to twice as wide as either word alone.
The banner regenerates as you type, which makes it cheap to try a few spellings. Shortening a word, dropping a space, or switching to upper case often gets a banner into the width you need faster than hunting through the font list.