Recipe Serving Size Scaler

WHAT IT DOES

Recipe Serving Size Scaler lets you instantly scale any recipe up or down to match your desired serving size. When you visit a recipe page, the extension adds a control panel with a slider, preset buttons, and a serving size display. Simply slide to adjust the scaling factor—from 0.25× to 4×—and all ingredient quantities in the recipe are automatically multiplied and updated in-place. The extension handles fractional measurements intelligently, converting 1/2 cup to 3/4 cup or 1 1/2 tablespoons, and rounds quantities to the nearest common fraction or decimal. The serving size display updates to show the new yield (e.g., "6 servings"), and preset buttons (½×, ¾×, 1×, 1.5×, 2×, 3×) provide one-click scaling. A reset button restores the original ingredient measurements with a single click.

WHERE IT RUNS

The extension works on every website with recipe content, including food blogs, cooking sites, recipe aggregators, and any page with structured ingredient lists. It runs locally in your browser, parsing ingredient quantities and updating the page DOM without sending any data to external servers. The extension supports all major browsers and adapts to both desktop and mobile viewports seamlessly.

HOW TO USE

After installation, the extension automatically adds a "Serving Size" control panel to recipe pages. Use the slider to adjust the scaling factor, or click preset buttons (½×, ¾×, 1×, 1.5×, 2×, 3×) for quick scaling. The serving size display updates in real-time to show the new number of servings. All ingredient quantities update automatically. To revert to the original recipe, click the "Reset" button. To customize the experience, open the extension panel and set your default multiplier (½× to 3×) that will be applied when the page loads. Toggle "Show scaling factor display" to show or hide the current multiplier. Toggle "Auto-detect serving size" to enable or automatic detection. Set the rounding precision (0-4 decimal places) for scaled quantities. For per-site customization, enable or disable the extension on specific websites using the per-site controls.

THE ACTUAL MECHANISM — INGREDIENT PARSING WITH FRACTION-INTELLIGENT QUANTITY SCALING

The extension uses a comprehensive ingredient parsing pipeline. First, it detects ingredient elements using a wide range of selectors (.ingredients li, .ingredient-list li, [itemprop="recipeIngredient"], and many more). For each ingredient, it parses the text to extract the numeric quantity using a multi-stage parser that handles fractions (½, ⅓, ¾), mixed numbers (1 1/2), simple fractions (1/2), and decimals. The parser uses a fraction map to convert Unicode fractions to decimal values. When scaling, the extension multiplies the quantity by the scaling factor, then formats the result using a fraction approximation algorithm that finds the closest common fraction (halves, thirds, quarters, fifths, sixths, eighths, tenths, twelfths, sixteenths) if the value is close to a common fraction; otherwise, it rounds to the user's specified precision. The scaled quantity is then recombined with the remaining text (unit and ingredient name) and the ingredient element's text content is updated. The serving size is detected from common serving selectors (.servings, .serves, .yield, [itemprop="recipeYield"]) or parsed from the page text. The serving size display updates to show the scaled yield based on the original serving size multiplied by the scaling factor.

THE PANEL

The settings panel is a lightweight, draggable overlay that appears in the center of your screen. You can reposition it by clicking and dragging the title bar; release it near the screen edge and it will snap into place automatically. To collapse the panel into a compact title bar, click the minimize button, expanding it again with the same control. The panel is fully responsive, adapting to different screen resolutions with a minimum width of 300px and a maximum of 480px. Press the Escape key at any time to dismiss the panel without applying changes. All controls—the enable/disable toggle, show scaling control button, reset button, default multiplier selector, factor display toggle, auto-detect toggle, rounding precision input, and per-site controls—are accessible within a clean, high-contrast interface that respects your system's color scheme.

PLEASE NOTE

This extension requires the free BotGentz companion extension to be installed and active, which provides the underlying DOM access and storage engine. The ingredient detection works on the majority of recipe sites but may not detect all custom implementations. If the scaling control doesn't appear, use the "Show Scaling Control" button in the panel to manually add it. The extension modifies the page's DOM by updating ingredient text—the original measurements are stored and can be restored with the reset button. The fraction approximation algorithm aims to produce natural-looking quantities but may not match every user's preference. No personal data, browsing history, or recipe content is ever collected, stored, or transmitted. All settings are saved using the browser's storage API and remain solely on your device. The extension does not inject ads, trackers, or analytics of any kind.