Every other font style covered on this site works the same way: swap each ASCII letter for a different code point that looks like a styled version of it. Strikethrough text works completely differently. There is no separate strikethrough alphabet in Unicode. Instead, a combining character called COMBINING LONG STROKE OVERLAY (U+0336) gets inserted after every single letter, and the rendering engine draws that stroke across the preceding character. The text "hello" with strikethrough is not five special characters — it's ten characters: h, combining-stroke, e, combining-stroke, l, combining-stroke, l, combining-stroke, o, combining-stroke.
How Combining Characters Work
Unicode's combining character mechanism exists primarily for accented letters in languages that need more diacritic combinations than have dedicated precomposed code points. A combining character has no width or shape of its own; it modifies the character immediately before it. Type the letter e followed by COMBINING ACUTE ACCENT (U+0301) and a rendering engine draws é, visually indistinguishable from the single precomposed code point U+00E9 (though the two are different underlying byte sequences — a subtlety called Unicode normalization that occasionally causes search or comparison bugs).
Strikethrough text generators repurpose this mechanism for a purpose it wasn't originally designed for: not adding a diacritic mark above or below a letter, but drawing a horizontal line through it. COMBINING LONG STROKE OVERLAY sits in the Combining Diacritical Marks for Symbols block (U+20D0–U+20FF), a block specifically intended for marks used on mathematical and technical symbols rather than ordinary text — which is a clue that this use case (styling plain words) is a repurposing of characters designed for something else, similar to how Mathematical Alphanumeric Symbols get repurposed from typesetting into social media bios.
The Character to Avoid: U+0338 Is Not the Same Mark
A second character is easy to confuse with the strikethrough stroke: COMBINING LONG SOLIDUS OVERLAY (U+0338). "Solidus" is the Unicode name for a forward slash. This character draws a diagonal slash through the preceding character, at roughly a 30-45 degree angle, the same visual pattern used for mathematical negation symbols like ≠ (not equal to, which is actually its own precomposed code point but conceptually built from = plus a slash overlay) and ∉ (not an element of).
Using U+0338 instead of U+0336 produces text that looks slashed through diagonally rather than struck through horizontally — visually similar enough at a glance that the mistake is easy to make and easy to miss, but distinct enough that careful readers notice the difference. A strikethrough generator that accidentally uses the solidus overlay is producing something closer to a mathematical negation mark than conventional editorial strikethrough.
Why Character Count Matters More Here Than Anywhere Else
Every other Unicode font style on this site produces one output character per one input character (with rare exceptions like decorated/separator styles that deliberately expand the string). Strikethrough always doubles the code point count: every visible letter requires its combining stroke character immediately after it. A 20-character phrase becomes 40 code points once struck through.
This matters directly for character-limited fields. Since COMBINING LONG STROKE OVERLAY (U+0336) is in the Basic Multilingual Plane, each instance costs 1 UTF-16 code unit on Twitter's counter — there's no surrogate-pair doubling the way there is for SMP styles like Mathematical Script. But the doubling still happens at the code-point level: a 280-character Twitter limit accommodates only about 140 struck-through letters, because each visible letter needs two code points (the letter plus its stroke) to render. TikTok's 80-character bio field fits roughly 40 struck-through letters for the same reason. This is a hard mathematical ceiling that applies regardless of which platform's specific counting method is in play, because it's about code point count, not UTF-16 width.
Why Strikethrough Sometimes Looks Broken or Uneven
Combining marks are positioned by the rendering engine relative to the glyph they follow, and different fonts calculate that position slightly differently. On some platforms and fonts, the stroke sits centered through the letter's x-height; on others it sits slightly higher or lower, or doesn't perfectly align between adjacent letters, giving the strikethrough line a faintly broken or stepped appearance rather than one continuous line. This is a font rendering behavior, not a flaw in the character choice — the same text can look cleanly struck-through in one app and slightly uneven in another, because each app's text renderer (and the font it falls back to for that code point) makes its own positioning decisions.
Combining marks after emoji, numbers, or punctuation can render unpredictably, since font support for stacking a combining overlay on those specific glyphs varies. Testing the actual output on the target platform (Instagram, Discord, iMessage) before relying on strikethrough for something important is the only reliable way to know how it will look.
The Same Mechanism Powers Underline Text
Underline text generators use the identical technique with a different combining character: COMBINING LOW LINE (U+0332), which draws a line beneath rather than through the preceding letter. Some generators offer a double-underline effect using COMBINING DOUBLE LOW LINE (U+0333). All three combining marks (strikethrough, underline, double underline) share the same doubling-cost and rendering-inconsistency behavior described above, because they're the same class of character used the same way.
Where Strikethrough Text Is Used
On platforms without native strikethrough formatting in a given field — Instagram bios and captions, Discord fields outside message bodies, TikTok bios, Facebook posts on some clients — Unicode combining-character strikethrough is the only way to produce a struck-through look. WhatsApp and Discord message bodies have native markdown strikethrough (~text~ and ~~text~~ respectively) that doesn't need Unicode at all and renders more reliably, so Unicode strikethrough is worth reserving for exactly the fields where no native formatting option exists.
The Strikethrough Text Generator inserts the correct combining mark, not the solidus overlay, after every character automatically.
It's worth noting where this technique isn't needed: WhatsApp and Discord message bodies both have native strikethrough markdown (~text~ and ~~text~~ respectively) that renders more reliably than the Unicode combining-mark approach and doesn't cost extra characters. Reserve the Unicode version for fields with no native formatting option, like bios, display names, and profile fields.