How this instrument works
Real underlining is formatting: an HTML underline tag, a word processor's underline button, a rich-text toggle — all instructions attached to text that a renderer applies or ignores. Unicode has a different tool for the same visual effect: combining characters, zero-width marks that stack onto the character before them rather than replacing it. A combining low line, U+0332, placed after any letter draws a line directly beneath it, and because the mark travels with the character in the same plain-text string, it survives being pasted into fields with no underline button at all — bios, usernames, plain-text notes, comment boxes.
This tool appends U+0332 after every single character in your input, including spaces, which is what keeps the underline continuous under multi-word text instead of breaking at each gap. It's worth distinguishing from a similarly built sibling tool on this site, strikethrough text, which uses a different combining mark entirely — U+0336, the combining long stroke overlay, which cuts through the middle of the character instead of sitting beneath it. Both work the same way mechanically, but they produce opposite visual effects, and it's easy to mix them up if you only remember that a combining character makes a line through text.
- Type or paste your text — up to 2,000 characters.
- Each character, including spaces, gets a combining low line appended right after it.
- Read the underlined result as it updates with every keystroke.
- Copy it and paste it anywhere plain text is accepted — bios, comments, chat messages.
Worked example — underlining across a word gap
Typing hello world produces h̲e̲l̲l̲o̲ ̲w̲o̲r̲l̲d̲ — 11 visible characters in the input becoming 22 Unicode code points in the output, because the space between the words gets its own combining low line too, not just the 10 letters. That's a deliberate choice: skip the space and the underline would visibly break in the gap, reading as two separately underlined words rather than one continuous phrase.
This matters for anyone using the tool to emphasize a run of text somewhere with no real underline button — a product review, a forum reply, a caption. Underline every character, space included, and the line reads as one unbroken stroke under the whole phrase, the way underlining normally looks in a word processor rather than under each word individually.
Questions
Why does underlining a phrase also mark the space between words?
Because skipping the space would break the underline visually right where the gap falls, making a phrase look like two separately underlined words instead of one continuous one. This tool appends the combining low line, U+0332, after every character in your input including spaces, which is what keeps the line unbroken under multi-word text — matching how underlining normally looks in a word processor.
Is this different from the strikethrough text tool on this site?
Yes, even though both work the same way mechanically. This tool appends U+0332, the combining low line, which draws beneath each character. Strikethrough text uses a different mark, U+0336, the combining long stroke overlay, which draws through the middle of each character instead. They're built from the same Unicode mechanism — combining characters — but produce visually opposite effects, so don't assume one tool's output can substitute for the other's.
Will the underline display the same way in every app?
Mostly, but rendering quality varies by font and platform. Some fonts position the combining low line slightly differently, and letters with descenders — g, j, p, q, y — can occasionally make the line look uneven or overlap the character below it, since the mark is designed to sit under an average letter, not adapt to each glyph's exact shape. It always displays as an underline; how tidy it looks depends on the font.
Will this underlined text paste correctly into every platform?
Usually, but not universally. Some platforms filter or limit combining characters as a spam or abuse precaution, since stacking many combining marks on one character is also how novelty "glitch" text effects are built — a legitimate single low line per character rarely triggers this, but a small number of strict input fields (some usernames, some form validators) may strip or reject it.
Can I remove the underline once I've pasted it somewhere?
Not with this tool automatically — it only adds the combining low line, it doesn't strip it back out. If you need the plain version again, retype or paste your original unconverted text; there's no built-in undo here, so it's worth keeping your source text saved separately if you might need the plain version later.