Ruler

What is Ruler?

Ruler is a native Mac measurement utility for people who need to measure items directly on their screen. It helps with visual checks such as UI spacing, on-screen dimensions, and angle measurement while you work in other apps. The app includes ruler and protractor tools, can stay above other windows, and shows live values as you move the pointer. It supports common measurement units including centimeters, inches, and pixels, which makes it useful for design, development, and general reference tasks. Quick switching and rotation controls are built in so users can adjust the measuring tool without interrupting their workflow. Ruler is published by Jinzhenyu for macOS.

Key features

• Measure on-screen length in centimeters, inches, and pixels.
• Track the mouse pointer and show real-time measurement values.
• Use a protractor to check angles in different directions.
• Keep the measuring tool above other windows while you work.
• Rotate the ruler with multiple control methods.
• Quickly switch between measurement modes with keyboard actions.

Safety overview

Status: Mostly safe

This app’s behavior is consistent with a screen measurement utility that stays visible over other windows. Because it works on top of other apps and tracks pointer position for measurement, review any accessibility or screen-related permissions carefully and grant them only if you use those features. If you installed it intentionally for on-screen measuring, this is a normal use case for the app.

Recommendation: Keep Ruler if you use it for design, layout, or screen measurement tasks. If you do not use on-screen measuring tools, you can remove it without affecting macOS or unrelated apps.

Common paths

• /Applications/Ruler.app

Preference paths

• ~/Library/Preferences/com.jinzhenyu.ruler.plist

Related can I delete pages

• ~/Library/Preferences/com.jinzhenyu.ruler.plist

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