How Unicode Strikethrough Text Actually Works
A plain-language guide to combining marks, why crossed out text survives copy and paste, and where the trick breaks down.
Combining marks, not formatting
Normal strikethrough in a word processor or on the web is formatting: the strike is a style applied on top of ordinary letters, and it disappears the moment you copy the text into a field that has no styling. This tool takes a different route. It uses Unicode combining marks, which are code points designed to sit on top of the character before them. The Combining Long Stroke Overlay draws a line through a letter, the Combining Low Line draws one beneath it, and the Combining Long Solidus Overlay draws a diagonal slash. Because the mark is a character in its own right, the visual effect is stored in the text and does not depend on any app remembering your formatting.
Why it survives copy and paste
When you copy decorated text, you copy the letters and their combining marks together as a single run of plain characters. Paste that run into Discord, an Instagram bio or a Telegram message and the receiving app simply renders the Unicode it was given, marks included. This is what lets you fake strikethrough in places that offer no formatting toolbar. The trade-off is length: every decorated letter is now two code points instead of one, so a short crossed out phrase can eat noticeably into a platform character limit.
Where the trick breaks down
Combining marks are widely supported but not universal. Systems that strip characters outside the basic ASCII set, some plain-text email clients, certain database fields and a handful of legacy apps will drop the marks and leave you with bare letters. Rendering also varies by font. On most modern fonts the line sits cleanly across the glyph, but on narrow or unusual typefaces the overlay can look slightly off center. If a clean, guaranteed strike matters, native strikethrough in an editor that supports it is the safer choice.
Accessibility and good taste
The underlying letters are never changed, so a plain-text search for a word still matches its decorated version, and most screen readers read the base characters. Even so, some assistive technology announces each combining mark or reads the sequence awkwardly, which makes heavily decorated text tiring to hear. Underline styling can also be mistaken for a hyperlink. Use these styles for a light touch, a struck-through price, a joke edit or a stylized handle, rather than for long passages or anything that must be fully readable by everyone.