Compact Screen Ruler

Small always-on-top screen ruler for measuring on-screen distances.

Download the latest release

Current version: v1.1.0

Features

• Frameless ruler window that stays on top.
• Resize from edges and corners.
• Drag to move the ruler (LMB in the center area, or MMB from anywhere).
• Hold Ctrl to snap when moving or resizing.
• Snap to screen edges by default when moving or resizing (hold Shift to disable).
• Right-click measure mode shows crosshair lines and live X/Y distance from the window origin.
• Set exact position/size.
• Light/dark color inversion and transparency toggle.
• Aspect ratio lock.
• Unit toggle for measurements (px, cm, inches).
• Copy current ruler dimensions to clipboard.
• Screenshot capture of the screen area behind the ruler.
• Clickthrough mode to interact with apps behind the ruler.

Hotkeys

• Right Click: Measuring mode
• Q or Ctrl+Q: Quit
• Ctrl (hold): Snap move/resize to medium tick spacing (10px, 0.5cm, 0.25in)
• Ctrl+C: Copy current dimensions to clipboard
• Shift (hold): Disable screen-edge snap
• S: Set exact position and size
• T: Toggle transparency
• I: Toggle light/dark colors
• F: Flip axes (swap width/height)
• R: Reset to defaults
• L: Toggle aspect ratio lock
• U: Toggle measurement units (px, cm, in)
• G: Toggle full-window grid from tick marks
• C: Toggle clickthrough mode
• Ctrl+S: Save screenshot of area behind ruler
• F1 or H: Open help

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Development

Requirements

• Python 3.11+
• PyQt6
• Nuitka (for building release executable)

Install dependencies:

pip install -r requirements.txt

Run

py -3.11 screen_ruler.py

Or use:

• launch_screen_ruler.bat

Build

make.bat

• This builds a standalone Windows executable with Nuitka and creates a zip you can upload directly to GitHub Releases:

• build/release/Compact-Screen-Ruler-v1.0.0-win64.zip