Ruler

Need to measure a small object? Turn your phone into a digital ruler with a clear on-screen scale. Ruler lets you measure lengths in centimeters (cm), millimeters (mm), and inches using adjustable measurement markers.

This screen ruler app is perfect for quickly checking the size of small everyday objects, from coins and cards to screws and small parts. No physical ruler needed for quick estimates, and no camera or AR required.

SCREEN RULER FEATURES

• Measure small objects directly on your phone screen.
• Choose centimeters, millimeters, fractional inches or decimal inches.
• Display metric and imperial ruler scales on opposite edges.
• Drag adjustable markers to measure the distance between two points.
• Fine-tune marker positions or enter coordinates manually.
• Lock markers, undo changes or reset measurements.
• Use 2D ruler mode to measure width and height together.
• Flip the ruler scale origin to match your measuring needs.
• Share measurements as text with other apps.

CALIBRATE YOUR DIGITAL RULER

Every phone has a different display. Ruler includes screen calibration to help you get more reliable measurements.

Use a physical ruler or another reference with a known length of at least 20 mm to calibrate the horizontal and vertical scales.

Your calibration settings, marker positions and preferences are saved locally for your next session.

SIMPLE AND EASY TO USE

Ruler is designed to make everyday measurements quick and convenient.

• Full-screen ruler in landscape orientation.
• Clean measuring scale with hideable controls.
• Adjustable measurement units and orientation.
• Optional reduced animations and keep-screen-awake setting.
• No account required and no ads.

Whether you're measuring small items at home, checking dimensions for a craft project or simply need a pocket ruler, Ruler provides a convenient digital measuring tool right on your Android screen.

IMPORTANT TO KNOW

This on-screen ruler measures only objects that fit within the usable display. The initial scale is an estimate, so calibrate both axes and verify measurements against a physical ruler before relying on them. Recalibrate after display or resolution changes.

Ruler is not a certified measuring instrument and does not measure distances through the camera or AR. Protect your screen from scratches when measuring objects.