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Free Bionic Reading Converter

Convert any text to bionic reading format β€” the first letters of each word are bolded to help your eyes focus and read faster.

Works offline once loaded

649 characters Β· 105 words

Higher = more letters bolded per word

Bionic preview

Reading is a complex cognitive process of decoding symbols to derive meaning. Bionic Reading is a method of typographically representing text that aims to facilitate the reading process by guiding the eyes through it with artificial fixation points. The reader focuses only on the highlighted initial letters, while the brain completes the word.

This is not the same as speed reading. The technique was developed by Swiss typographic designer Renato Casutt in 2016 and has been popularized by various reading apps. Studies on its effectiveness are mixed β€” some people find it helpful, others see no benefit. Try it for yourself with any text below.

πŸ’‘ Bionic reading guides your eyes through text by bolding the first part of each word β€” the brain fills in the rest from the bolded letters. Effectiveness varies: some readers find it speeds them up, others see no difference. Try different fixation amounts to find what works for you.

Common uses

  • Read Academic Texts FasterConvert lecture notes, textbook chapters, or research papers to bionic format for quicker review.
  • Reading Aid for DyslexiaSome readers with dyslexia find bionic formatting helps anchor their eye to each word's starting letters.
  • Quickly Scan Long EmailsPaste long emails or newsletters into the tool to scan faster.
  • Read News Articles FasterPaste articles from news sites into the tool for a speed-reading experience.
  • Reading Aid for Language LearnersBionic format may help focus on key letter clusters in a foreign language.

How It Works

Bionic Reader applies a hand-written tokenizer directly in your browser β€” no library, no server. It scans every word using a Unicode-aware regular expression and bolds a calculated leading portion, based on the idea that the eye "fixates" on the start of a word to recognize it.

  1. 1
    Unicode tokenization
    A Unicode property-escape regex (\p{L}\p{M}) walks the raw text and identifies every word, including accented characters and non-ASCII scripts. Contractions and hyphenated compounds like "don't" and "self-aware" are kept as single tokens so the bold falls at a natural fixation point.
  2. 2
    Fixation length calculation
    For each token, the bold prefix length is computed as Math.ceil(word.length * fixationPct), where fixationPct is a slider you control (20%–80%, default 50%). A minimum of 1 character is enforced so short words always get at least one bold letter.
  3. 3
    Safe HTML construction
    Non-word spans between tokens are HTML-escaped before insertion, preventing any accidental tag injection. Each word is split into a b element prefix and a plain suffix, then the segments are concatenated into a single HTML string rendered live in the preview panel.
  4. 4
    Clipboard export
    You can copy the result as formatted rich text (using the Clipboard API's ClipboardItem with a text/html blob, so bolding survives paste into Gmail, Word, or Notion), as plain text, or as raw HTML markup β€” all three paths use navigator.clipboard entirely in-browser.

Related Tools

πŸ”€

Dyslexia-Friendly Reformatter

Reformat any text for easier reading: generous letter and word spacing, taller lines, a capped line width, legible fonts, a soft background tint, and optional bold word-starts. All in your browser.

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⚑

Speed Reader (RSVP)

Read faster with Rapid Serial Visual Presentation: your text flashes one word at a time at an adjustable 100–1200 WPM, with the optimal-recognition-point letter centered. Paste, set a speed, and press play. All in your browser.

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πŸ“

Reading Ruler

A reading focus aid that dims everything except one adjustable band of text, which follows your cursor or the arrow keys. Helpful for dyslexia and ADHD. Paste your text β€” nothing is uploaded.

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Frequently Asked Questions