Text to ASCII art — words set in large letters

Almost always because the message is being rendered in a proportional font rather than a monospaced one. Banner letters are built from a fixed grid of character cells, so they only hold their shape where every character is the same width — the moment an i is narrower than an m, the columns stop lining up and the letters shear. In Slack, Discord and most chat clients the fix is to wrap the message in a triple-backtick code block, which is what the Markdown option here produces. The second cause is trailing spaces: several clients strip them, so a banner that relies on them to keep its rectangle arrives ragged on the right. That is why trailing spaces are trimmed by default here, and why the dot-matrix face draws its background as periods instead of leaving it blank.

No, and that is worth knowing before you paste it into something old. ASCII is 128 code points and its printable range is 0x20 to 0x7E — the letters, digits and punctuation on a US keyboard, one byte each. The full block used by the solid and half-block faces is U+2588, a Unicode character that costs three bytes in UTF-8 and renders as a question mark or a box anywhere the encoding is not UTF-8. Four of the six faces here are checked to emit nothing outside 0x20 to 0x7E; the other two are labeled, and the panel under every result reports the exact code points and how many extra bytes they cost. HELLO drawn in the solid block face is 408 characters but 700 bytes — the same picture at 1.7 times the storage — while in the hash face 207 characters is exactly 207 bytes.

Because a banner alphabet is one case, and every character in it is drawn on the same grid. Real lowercase needs descenders — the tails on g, j, p, q and y — which means either two more rows on every letter in the alphabet or a g that sits on the baseline and stops being a g. Terminal banner programs have made the same choice since the 1970s. What this page does is fold your lowercase up to capitals rather than dropping it, and say so under the result, so a name typed in mixed case still comes back complete.

Because they light the same segments, exactly as they do on a calculator or a microwave clock. The three-row face is a seven-segment alphabet, and that construction has always had a small set of characters it cannot separate — it is also why B is drawn as a lowercase b and D as a lowercase d, since the uppercase forms would be indistinguishable from 8 and 0. The page derives the clash from the glyph table rather than from a list somebody typed, so it warns only when one of those characters is actually in your text. If the banner has to be read back character by character, a serial number or a registration, use one of the seven-row faces instead.

Yes, and the wrapper options exist so you do not have to add the comment markers by hand. The hash form covers shell, Python, Ruby, YAML and Dockerfiles; the double-slash form covers C, Java, JavaScript, Go and Rust. Prefer a line comment to a block comment where you have the choice, for one specific reason: a block comment can be closed early by the art itself. The three-row face draws a literal asterisk and a literal slash, so a banner containing both in the wrong order ends the comment where it appears and leaves the remaining lines to be parsed as code. This page checks for that and refuses to pretend it did not happen.

A monospaced character cell is roughly twice as tall as it is wide, so a letter plotted one cell per grid square comes out at about half the proportion it was drawn at. The 5 x 7 matrix behind four of these faces is meant to read as a five-wide, seven-tall letter; at one column per cell it occupies five columns and seven rows, which on screen is a tall thin letter. The double-width faces draw two columns per cell, which puts the shape back at roughly its intended proportion at the cost of twice the columns — six letters on an 80-column line instead of thirteen. It is the same correction the ASCII pages that start from a photograph have to make, in the opposite direction.

Pick the width from the destination, not from how the banner looks on this page. 80 columns is the terminal default and what a GitHub diff view renders at; 72 is the conventional ceiling for the body of a git commit message; a printed sheet at 7pt monospace holds roughly 128 columns across A4 with normal margins. Whatever you choose, the wrap happens at the spaces between words and each band is separated by a blank row, so a two-word phrase becomes two stacked banners rather than one banner cut through the middle. The face is the bigger lever than the width: the same word runs 82 columns in the double-width faces, 41 in the single-width hash face and 27 in the three-row segment one.