Drop an image here
or click Upload Image above
Supports PNG, JPG, GIF, WebP, BMP, SVG
// upload an image and measure pixel distances with precision
Upload any image and draw measurement lines to calculate pixel distances, angles, and dimensions instantly. Free browser-based pixel ruler tool.
Drop an image here
or click Upload Image above
Supports PNG, JPG, GIF, WebP, BMP, SVG
Click "Upload Image" or drag and drop any image file onto the canvas area.
Click and drag on the image to draw a line. Hold Shift to snap to 45° angles.
View pixel distance, real-world distance, and angle in the measurements table below. Export to CSV anytime.
Pixel Ruler lets you draw measurement lines on any image directly in your browser. Instantly see the pixel distance, real-world equivalent (via scale factor), and angle for each line. No software to install — works with PNG, JPG, WebP, GIF, BMP, and SVG.
No. Pixel Ruler is completely browser-based. Your image never leaves your device — all processing happens locally using the HTML5 Canvas API.
Any format your browser can display: PNG, JPG/JPEG, GIF, WebP, BMP, and SVG. For best results use PNG or JPG.
Enter the scale factor in the toolbar — specify how many pixels equal 1 unit (mm, cm, in, or pt). For example, if your image is 96 DPI, enter 96 pixels = 1 in. The measurements table will then show both pixel and real-world distances.
Yes! You can draw as many lines as you need. Each line appears in the measurements table with its own distance, angle, and coordinate data. Use the Undo button to remove the last line, or Clear Lines to remove all.
Hold the Shift key while drawing a line to constrain it to 0°, 45°, 90°, 135°, or 180° — perfect for measuring horizontal, vertical, or diagonal elements.
Yes. Click the Export CSV button to download all your measurement lines as a CSV file. The file includes line number, pixel distance, real-world distance, angle, and start/end coordinates.
A pixel ruler is an online tool that lets you draw measurement lines on any image to calculate precise pixel distances, angles, and coordinates. Designers, developers, architects, and photographers use pixel rulers to verify spacing, check proportions, and analyze image dimensions without needing dedicated desktop software like Photoshop or Illustrator.
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The tool uses the HTML5 Canvas API to render your image inside the browser. When you click and drag across the canvas, it records the start and end coordinates of your line. Using the Pythagorean theorem, it calculates the straight-line distance between those two points in pixels: distance = √((x2-x1)² + (y2-y1)²). The angle is calculated using the arctangent function: angle = atan2(y2-y1, x2-x1), converted to degrees.
Pixel measurements are only useful if you know the relationship between pixels and real-world units. This is where the scale factor comes in. If you know your image's DPI (dots per inch), you can set 1 inch = your DPI value in pixels. For example:
Once you set the scale, all measurements automatically show both the raw pixel count and the real-world equivalent in your chosen unit (mm, cm, in, or pt).
Traditional pixel measuring tools require software installation — Photoshop, Figma, GIMP, or dedicated ruler apps. A browser-based pixel ruler removes that friction entirely. Your image stays private because it never leaves your browser. There's nothing to install, no account to create, and no file size limits beyond what your browser can handle. For quick measurement tasks, it's the fastest option available.
UI/UX Design: Verify that spacing, padding, and margins match your design spec. Check that buttons and icons have consistent dimensions across screens. Measure the exact distance between UI elements to ensure they follow your design system.
Web Development: Measure elements in design mockups before coding. Confirm that your CSS pixel values match the intended design. Check image dimensions before writing width and height attributes.
Photography & Composition: Analyze the rule of thirds or golden ratio in your photos. Measure the proportion of subjects to backgrounds. Check whether horizons are level by drawing a horizontal reference line.
Architecture & Engineering: Measure dimensions on blueprint exports or scanned drawings when you have a known scale. Calculate distances between labeled points on site plans or floor plans.
Game Development: Verify sprite sheet tile sizes, hitbox dimensions, and character proportions. Ensure UI elements are the right size for target screen resolutions.
Use the zoom feature to get precise line placement on high-detail images. The canvas zoom does not affect pixel values — measurements always reflect the original image's pixel coordinates, regardless of zoom level. Hold Shift while drawing to snap to 45° increments for perfectly horizontal, vertical, or diagonal lines. If you need to measure curved paths, draw multiple short straight lines to approximate the curve and sum the distances from the measurements table.
After drawing your lines, click Export CSV to download a spreadsheet-compatible file with all measurements. Each row contains the line number, pixel distance, real-world distance (if scale is set), angle in degrees, and the X/Y coordinates of the start and end points. This makes it easy to document measurements for design reviews, client presentations, or technical specifications.
Browser-based pixel rulers complement dedicated design tools rather than replacing them. Photoshop and Figma offer more sophisticated measurement features including guides, smart guides, and component spacing — but require accounts or subscriptions. For quick, one-off measurements or when working on a machine without design software, an online pixel ruler is the most practical solution. It's also useful for non-designers who need to take a measurement but don't have access to professional tools.