Screen Ruler - Measure Pixels on Screen
Drag to measure areas in pixels, track mouse coordinates in real-time, and view your screen resolution info.
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What Is a Screen Ruler?
A screen ruler lets you measure distances on your screen in pixels by dragging a selection area. It shows horizontal and vertical rulers with tick marks, displays your mouse position in real-time, and reports the width and height of any region you select. Useful for web designers, UI developers, and anyone who needs precise pixel measurements without installing software.
How to Measure Pixels on Screen
- Choose Mode — Select Rectangle (area) or Line (distance) mode
- Click and Drag — Click on the measurement canvas and drag to draw your selection
- Read Results — Width, height, and mouse position update in real-time as you drag
- View History — Each completed measurement is saved in the history list below
- Check Screen Info — Your screen resolution, viewport size, and device pixel ratio are shown at the top
Why Use This Screen Ruler?
- No Installation — Works directly in your browser, no extensions or downloads needed
- Rectangle & Line Modes — Measure areas or straight-line distances
- Pixel-Perfect Rulers — Horizontal and vertical rulers with 10px/50px/100px tick marks
- Real-Time Tracking — Mouse coordinates update instantly as you move
- Screen Info — Instantly see your screen resolution, viewport dimensions, and DPR
- Measurement History — All measurements are saved for reference until you clear them
- Privacy — Everything runs in your browser with zero data sent anywhere
FreeToolbox vs Other Screen Rulers
| Feature | FreeToolbox | PicPick | MeasureIt Extension |
|---|---|---|---|
| Installation | None (browser) | Desktop app | Browser extension |
| Rectangle + Line | Yes | Yes | Rectangle only |
| Rulers with ticks | Yes | Yes | No |
| Screen resolution info | Yes | No | No |
| Measurement history | Yes | No | No |
| Dark mode | Yes | System | No |
| Price | Free | Free/Paid | Free |
FAQ
Does this measure my actual screen?
It measures pixel distances within the tool's canvas area. The rulers and coordinates are in CSS pixels. For true screen measurements, multiply by your device pixel ratio (shown in the Screen Info section).
Can I measure elements on a webpage?
This tool measures within its own canvas. To measure webpage elements, you can use browser DevTools (F12) or take a screenshot and measure it with this tool.
What is Device Pixel Ratio?
Device Pixel Ratio (DPR) is the ratio of physical pixels to CSS pixels on your screen. A DPR of 2 means each CSS pixel is rendered using 2×2 physical pixels, common on Retina/HiDPI displays.
Is the measurement data saved?
Measurements are kept in memory during your session only. They are not saved to localStorage or sent to any server. Refreshing the page clears all measurements.
Can I switch between rectangle and line mode?
Yes. Click the Rectangle or Line button above the canvas to switch modes at any time. Previous measurements of both types remain visible on the canvas.