MeasureIt for Firefox adds a pixel ruler for checking the width, height, and alignment of elements on a webpage. Draw a rectangular measurement box by clicking and dragging, then move or resize it to inspect a different area. Arrow-key controls adjust its size, while Ctrl with the arrow keys nudges its position for precise alignment. It is a simple aid for web design, layout checks, and quick comparisons without leaving the browser.
| Author: | Kevin Freitas |
| License: | Freeware |
| Price: | FREE |
| Released: | Jun 30, 2019 |
| File size: | 297 kB |
| Downloads: | 324 |
| Keywords: | MeasureIt, pixel, pixel width and height, web development tool, firefox pixel ruler, Kevin Freitas, measure page element size, pixel perfect design, Firefox extension, on-screen ruler, web design ruler, check webpage alignment, webpage measurement tool, pixel height, width, Measure, pixel width |
| Author URL: | http://www.kevinfreitas.net/ |
MeasureIt for Firefox is a lightweight browser extension for checking dimensions and alignment directly on a webpage. It is useful for web designers, developers, and anyone comparing the visible size or position of page elements without opening separate image-editing or measurement software. The extension places a pixel ruler over the page, so measurements can be taken where the content appears in the browser.
To measure an area, the user switches MeasureIt on from its toolbar or status-bar button, then clicks and drags to draw a rectangular ruler. Its width and height show the size of the selected region in pixels. This makes it practical to check image dimensions, compare the spacing between page elements, or see whether a layout region matches a target size. The ruler can be repositioned by clicking and holding it, and its lower-right corner can be dragged to change its dimensions.
Keyboard controls allow more precise adjustments than dragging alone. The arrow keys change the ruler's size one pixel at a time; holding Shift increases the adjustment to five pixels. Holding Ctrl while using the arrow keys nudges the ruler's position by one pixel, or by five pixels when Ctrl and Shift are used together. These small increments help when aligning a measurement with an edge or checking a narrow gap. The close control removes an individual ruler, while clicking outside an existing ruler starts another measurement.
MeasureIt can support routine layout checks, quick comparisons of page components, and pixel-level inspection during web design or testing. It measures the visible webpage rather than editing its content, and its controls are limited to drawing, resizing, moving, and closing ruler boxes. Pressing Esc turns the extension off when measurement is finished.
The extension is freeware and is intended for use inside Firefox. Its listed Windows support ranges from older Windows releases through Windows 11, but the actual ability to install it depends on compatibility with the Firefox version in use. The small extension provides an on-page measuring tool rather than a full design or browser-inspection suite.