RulerApp vs Ruler & Digital Caliper

Turn your iPhone or iPad into a precise on-screen ruler. Hold any small object against the screen and read its exact size — no tape measure, no guesswork. FEATURES • Accurate out of the box — no manual calibration. Ruler scale is calculated from your exact device's screen density. • Switch between centimeters, inches, or both at once. • Drag to drop a crosshair anywhere and read precise X/Y measurements from the corner. • Toggle a grid overlay (off, major lines, or major + minor) for finer alignment. • iPad extras: hover measurements with a trackpad or Apple Pencil, and keyboard shortcuts (U for units, G for grid) with a hardware keyboard. Simple, fast, and always in your pocket.

Measure small, flat objects on your iPhone with an edge ruler and two-jaw digital caliper. On supported iPhone models, start with an approximate device-based screen scale. For a physical check, align a ruler with a 20 mm reference on screen. Lifetime access requires a separate one-time purchase and adds repeated measurements and a session workspace: view a result, use it as a reference, and compare the next object. Results and references remain in the current session. TWO FOCUSED TOOLS • Edge ruler with a movable origin and end marker • Digital caliper with two independently adjustable jaws • Magnified contact guide for placing markers at object edges • Fine-adjust controls for small position changes • Reset markers without resetting calibration FOUR UNIT FORMATS • Millimeters • Centimeters • Decimal inches • Fractional inches, rounded to the nearest 1/64 BUILT FOR REAL-WORLD ALIGNMENT Keep a small object flat against the usable screen edge, move the contact points to its edges, and read the result. Switch tools and units as you work. Use portrait or either landscape orientation, and lock orientation while aligning an object. PRIVATE BY DESIGN Measurement values and marker positions are calculated on your iPhone. There is no account, advertising, camera access, or measurement server. Limited privacy-conscious product analytics never include measurement values, marker positions, or calibration data. Calibration and preferences are stored locally. A PRACTICAL SCREEN TOOL Results depend on calibration, alignment, display settings, screen protectors or cases, and the object being measured. Recalibrate after changing iPhone or Display Zoom. For important measurements, compare the result with a known physical reference. Ruler & Digital Caliper is not a certified measuring instrument. Support: https://rulercaliper.app/support Privacy Policy: https://rulercaliper.app/privacy Terms of Use: https://rulercaliper.app/terms