Substack Reading Time Badge

WHAT IT DOES

Substack Reading Time Badge automatically detects Substack article content, calculates the estimated reading time based on word count (using the standard average of 238 words per minute), and displays a compact badge near the article title or header showing the reading time and word count. The tool also provides an optional reading progress bar at the top of the page that fills as you scroll, showing how much of the article you have read. This helps readers quickly gauge article length, plan their reading time, and track their progress through long posts.

WHERE IT RUNS

This extension works exclusively on Substack at substack.com. It functions on post pages, article pages, and any page with substantial text content. The tool works across all Substack publications and adapts to dynamically loaded content.

HOW TO USE

Install the extension and navigate to any Substack article. A reading time badge appears near the title or at the top of the article showing the estimated reading time and word count. A thin progress bar appears at the very top of the page, filling as you scroll down. Use the overlay panel to customize the experience: toggle the reading time badge on or off, toggle the progress bar on or off, adjust the reading speed in words per minute (default 238) to match your personal reading pace, choose the badge position (Next to title or At top of content), and select the display format (Minutes only or Minutes + seconds). Click "Refresh Badge" to manually update the reading time after content changes.

TECHNICAL SECTION — READING TIME CALCULATION AND PROGRESS TRACKING

The extension uses a multi-strategy detection engine to find article content on Substack pages. It queries common content selectors including .post-content, .article-content, .body, and .content, falling back to the document body if no specific container is found. The word count is calculated by splitting the text content by whitespace and filtering empty strings. Reading time is calculated using the formula: (word count / words per minute) * 60 seconds, with the result displayed in minutes and optionally seconds. The progress bar tracks the user's scroll position relative to the total document height, updating in real-time with a smooth transition. Both the badge and progress bar are created using DOM manipulation with inline CSS for styling, ensuring they work without requiring external resources.

THE PANEL — DRAG / PER-SITE POSITION / SNAP / COLLAPSE / RESIZE / ESCAPE

The overlay panel is fully interactive and designed for seamless multitasking. Drag it anywhere on the screen using the handle at the top of the panel; the position is saved per site so it stays where you left it across sessions. The panel includes a snap-to-edge feature that gently anchors the overlay to the nearest screen edge when released. Click the collapse button to minimize the panel to a compact pill showing the current reading status; expand it again with a single click. Resize the panel vertically by dragging the bottom-right corner to view more controls. Press the Escape key at any time to instantly close the overlay; it reappears on the next page navigation or refresh.

PLEASE NOTE

This extension requires the free BotGentz companion extension to function, as it provides the underlying content script injection and cross-origin communication framework. No personal data, browsing history, or reading data is stored, transmitted, or shared. Settings are stored locally in your browser using GM_setValue and are never sent to any external server. The extension does not access or store login credentials, financial data, or personally identifiable information. The tool reads article content visible on the page and does not access Substack's API or any private data. Reading time is an estimate based on average reading speed and may vary by reader. Substack may update its page structure; the extension includes multiple detection strategies to maintain compatibility, but major redesigns may temporarily affect content detection. The progress bar works on scroll events and may have slight performance impact on very long pages.