Bionic Reading Converter
Type or paste text below, the leading letters of each word are bolded to help your eyes track faster.
About the Bionic Reading Converter
Bionic reading bolds roughly the first 40-50% of each word's letters (rounded up, with at least one letter bolded), a pattern some readers say helps their eyes fixate faster and keeps reading rhythm steady. Because the preview is built from real DOM nodes rather than raw HTML strings, anything pasted in that looks like markup is still treated as plain text and can never inject anything into the page.
Use "Copy Plain Text" for the unformatted words to paste elsewhere, or "Copy as HTML" for the bolded markup itself.
Whether it actually works is genuinely unsettled
Worth being upfront about, since this tool's own description leans on hedged language like "some readers say" rather than a settled claim: the evidence for bionic reading improving reading speed or comprehension is mixed at best, several studies that have tested it directly found no significant benefit over normal text for most readers, and a few even found it slightly slower. The underlying idea, that bolding the front of each word helps the brain guess the rest and lets the eye skip ahead, is intuitive, but intuitive isn't the same as proven. It's genuinely worth trying on a personal sample of text to see if it helps individually, some readers do report it feels easier to track, rather than assuming it's a universally validated reading-speed technique.
How the bold length is actually calculated
Each word's bold portion is 45% of its letter count, rounded up, with a floor of at least one bolded letter so even short words like "a" or "in" get some emphasis rather than none. Only the letters and apostrophes at the start of a token count toward that calculation, a word with trailing punctuation like "Hello," calculates its bold length from the five letters in "Hello," not six, so the comma itself is never partially bolded or miscounted as part of the word.
Why this can't be exploited to inject HTML
The preview is assembled using createElement and createTextNode rather than building an HTML string and inserting it with innerHTML, which means pasted text that happens to look like a tag, <script> or otherwise, is always treated as literal characters to display, never as markup to execute. This matters for a tool that renders arbitrary pasted text back onto the page, and it's specifically why "Copy as HTML" exists as a separate, deliberate action, the actual HTML markup is only ever generated on request for copying out, never used to build the live preview itself.
Where the bolded text is actually useful
Pasting the bolded HTML into an email client, a note-taking app, or a document editor that supports rich text is the main use, the bolding then displays natively wherever it's pasted rather than needing any special software to read it. It's less useful for anything that strips formatting on paste, plain text messaging apps or a code editor, for instance, where the bold tags would either be discarded entirely or show up as literal, distracting <strong> tags in the output rather than actual bold text.
Words versus non-word tokens
Only tokens made of letters and apostrophes get bolded, a run of digits, a symbol, or a piece of punctuation on its own passes through unchanged since there's no letter sequence within it to apply a bold ratio to. A hyphenated compound word like "well-known" only has its first segment, "well," included in the bold calculation, the hyphen and everything after it is treated as trailing punctuation rather than a second word to bold on its own, so the second half of a hyphenated word never gets its own bolding.
Frequently Asked Questions
Is there scientific proof that bionic reading actually improves reading speed?
Not conclusively. Several studies testing it directly found no significant benefit over normal text for most readers, and some found it slightly slower. The idea is intuitive, but the evidence is genuinely mixed, it's worth trying on personal text to see if it helps individually rather than assuming it's a proven technique.
How much of each word gets bolded?
Roughly 45% of each word's letters, rounded up, with at least one letter always bolded even for very short words. Only the leading letters and apostrophes count toward the calculation, trailing punctuation is excluded.
What's the difference between "Copy Plain Text" and "Copy as HTML"?
Plain text copies the original unformatted words, useful for pasting somewhere that doesn't support formatting. Copy as HTML copies the text with actual bold tags included, useful for pasting into a rich text editor, CMS, or email client that will render the bolding.
Is it safe to paste text that looks like HTML or code into this tool?
Yes. The preview is built using real DOM elements rather than an HTML string, so anything pasted in that looks like a tag is always displayed as literal text, never executed or rendered as markup.
Does the second half of a hyphenated word get bolded too?
No. Only the first segment before the hyphen is treated as a word and included in the bold calculation, the hyphen and everything after it is treated as trailing punctuation rather than a second word, so the portion after a hyphen never gets its own bolding.
Where does the bolded HTML actually work when pasted?
Anywhere that renders rich text, an email client, a note-taking app, or a document editor. It won't display as bold in something that strips formatting on paste, like a plain-text messaging app or a code editor, where the bold tags would either be discarded or show up as literal text instead.