Screen Pixel Ruler
Drag to measure screen element dimensions in pixels. Convert to mm and save multiple measurements.
• Click Start and drag to measure areas
• mm values depend on DPI setting (default 96)
• For accurate mm measurements, verify your monitor DPI
📏 What is Screen Ruler?
Screen Ruler measures on-screen areas by dragging to get pixel dimensions. It also converts to mm and inches based on your DPI (dots per inch) settings. Essential for UI/UX design, web development, and checking image sizes. Measure multiple areas simultaneously and keep a record of measurements.
📊 Common Display DPI Values
| Display | Typical DPI | Notes |
|---|---|---|
| Standard Monitor | 96 DPI | Windows default |
| MacBook Pro | 110-220 DPI | Retina display |
| 4K 27-inch | 163 DPI | High resolution |
| Smartphone | 300-500+ DPI | Ultra high density |
| 300+ DPI | Print quality standard |
💡 Screen Measurement Tips
- Check DPI: Find your monitor DPI in specs for accurate mm measurements
- Watch scaling: Windows/Mac display scaling affects pixel calculations
- Design review: Verify margins and button sizes match design specs
- Responsive testing: Measure element sizes across different resolutions
Frequently Asked Questions
How do I find my monitor DPI?▼
Check your monitor specifications, or divide horizontal resolution by screen width in inches. Example: 1920px / 23.8 inches ≈ 81 DPI. The default 96 DPI is a rough approximation.
Is it accurate when browser is zoomed?▼
No. Browser zoom (Ctrl+scroll) affects pixel calculations. Use 100% zoom level for accurate measurements.
Can I measure elements in other apps?▼
This tool only works within the browser measurement area. For full-screen measurements, use your OS screenshot tools or dedicated screen measurement applications.