Independent Bold-Prefix Formatter | Bionic-Style Text Tool

How to use this tool

Paste or type text into the input box; conversion stays in your browser.
Adjust Fixation to choose the approximate bold fraction, from 25% to 65%.
Read the preview or copy HTML, formatted clipboard content, or Unicode bold text.

How bold-prefix formatting works

This page offers an independent bold-prefix text formatter. It marks the beginning of supported words in bold, leaving the rest in regular weight. Similar-looking formatting is sometimes called “bionic-style,” but this converter is not the official Bionic Reading system, does not claim to reproduce its algorithm, and uses no account or text upload. Your pasted text is processed locally in this browser.

The Fixation slider controls the approximate fraction of each supported word that is bold: level 1 targets 25%, level 2 targets 35%, level 3 targets 45%, level 4 targets 55%, and level 5 targets 65%. The converter rounds each prefix up to a whole character and keeps at least one character bold, so the displayed percentage is approximate. For example, at level 2 the word “Hello” becomes <b>He</b>llo. Short words can be fully bold, and the converter leaves punctuation, spaces, and unsupported scripts unchanged.

Use the preview to experiment with pasted notes, a paragraph from a draft, or other text you already have permission to use. Copy HTML preserves the exact <b> markup; Copy formatted places HTML and plain text on the clipboard for compatible rich-text editors, with an HTML-string fallback. Copy Unicode bold substitutes mathematical bold characters for ASCII letters in the bold prefix. That Unicode form is only a visual alternative: assistive technology may pronounce those characters differently, and search or text matching may not treat them like ordinary letters.

Bionic Reading® is a registered trademark of BRCG Casutt GmbH, which says Bionic Reading AG is its authorized partner. This independent Toolcroft bold-prefix converter is not affiliated with or endorsed by BRCG Casutt GmbH or Bionic Reading AG.

Evidence and individual experience

Claims that bold-prefix formatting increases reading speed or comprehension are not established. Independent studies have reported mixed results, including studies that found no reliable advantage for typical readers. People sometimes share personal experiences of changes in focus or place-keeping, including readers with ADHD or dyslexia; those anecdotes do not show that this formatting helps those conditions. Treat the preview as a personal formatting experiment, not a proven reading intervention or a substitute for accessibility supports that work for you.

Tips for trying the formatter

Start at Fixation 2, which targets about 35% of each supported word, then compare the same passage at another level. There is no setting that is known to work best for everyone. The amount actually bolded varies with word length because prefixes must contain whole characters; one- and two-letter words may be entirely bold. If you share the output, choose HTML or formatted clipboard content when the destination supports rich text. Use ordinary text when searchability or screen-reader pronunciation matters.

Frequently asked questions

What does this bold-prefix formatter do?

It independently bolds the beginning of supported words as a visual formatting choice. The result resembles some bionic-style text examples, but this tool does not implement or claim to match an official reading system.

What does the Fixation setting change?

Fixation controls the approximate bold fraction: level 1 is 25%, 2 is 35%, 3 is 45%, 4 is 55%, and 5 is 65%. Higher levels bold more of each supported word. Rounding and the minimum one-letter prefix mean short words may be fully bold.

How can I copy the formatted text?

Copy HTML copies the exact <b> markup string. Copy formatted writes HTML and plain text to the rich clipboard where supported, falling back to the HTML string. Copy Unicode bold replaces ASCII Latin letters in bold prefixes with mathematical bold characters; this is visual text and may affect accessibility or search.

Is this the official Bionic Reading system?

No. Bionic Reading® is a registered trademark of BRCG Casutt GmbH, which says Bionic Reading AG is its authorized partner. This independent Toolcroft bold-prefix converter is not affiliated with or endorsed by BRCG Casutt GmbH or Bionic Reading AG.