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Foldometer: Fold Angle Gauge icon
Built for Duo

Foldometer: Fold Angle Gauge

Measures the iPhone Duo hinge angle live, and serves as a level, protractor, slope meter and camera angle finder.

Matthew Purcell · Utilities · $0.99

View on the App StoreSave

iPhone screenshots

Foldometer: Fold Angle Gauge — iPhone screenshots 1
Foldometer: Fold Angle Gauge — iPhone screenshots 2

How it uses iPhone Duo

Open iPhone Duo and Foldometer turns its hinge into a precision instrument. Watch the two halves move on screen as you open

App Store descriptionWritten by the developer.

Your fold, measured. Open iPhone Duo and Foldometer turns its hinge into a precision instrument. Watch the two halves move on screen as you open and close it, read the exact angle between the displays, and feel a gentle tap when you land on a right angle or lie perfectly flat. It's the most fun way to see what your new foldable can do. Not on a foldable? Foldometer is a beautiful level, protractor, slope meter and camera angle finder for every iPhone and iPad. HINGE (IPHONE DUO) • The live angle between the two displays, from closed to fully open • An animated side view of your device that follows the hinge • Stand presets for Easel, Upright, Video call, Laptop and Reading, or save your own, with a tap when you reach them • Set a zero at any position to measure how far the hinge moves • Record the angle over time, then see a chart with the range and peak speed, and share it as an image or CSV FOLD GAUGE (IPHONE DUO) • Rest one half on a surface and lay the other against a second surface • Foldometer combines the hinge with the motion sensors to read each half's angle from horizontal, even when the first surface isn't level LEVEL • Stand iPhone on an edge to read its tilt, shown to a tenth of a degree • Lay it flat and it becomes a bubble level for any surface • Turn it on its side and the reading keeps counting, with "2.4° from level" right where you need it • Hold iPhone against one surface, tap Set Zero, then rotate to the next to read the angle between them SLOPE AND PITCH • Show any slope in degrees, percent grade, millimetres per metre, inches per foot or roof pitch • Set a target such as a 2% patio fall, a ¼ in/ft waste pipe, a 1:12 ramp or a 6/12 roof, and feel a tap when you hit it CAMERA • Measure angles you can't reach, like a roof line or a leaning post, by lining up arms over the camera view • Slopes read against the true horizon from the motion sensors, even if iPhone is tilted • Freeze the frame to fine-tune PROTRACTOR • Two draggable arms on a full 360° scale, with a tick of haptic feedback for every degree • Tap the reading to flip to the reflex angle PRECISION • Flip calibration: take a reading, turn iPhone around in place, take another. Calibrating on its back also corrects for the camera bump or a case. • Auto-Hold freezes the reading the moment iPhone comes to rest, so you can read it after moving away LOG AND WIDGETS • Save any reading with one tap, add notes like "Garage roof pitch", and export everything as CSV • Home Screen and Lock Screen widgets show your fold angle and newest reading DESIGNED FOR APPLE PLATFORMS • Built for iPhone Duo's displays: toolbars and tabs along the side, and layouts that adapt as you fold • Liquid Glass controls, light and dark appearances, and a layered icon • VoiceOver, Dynamic Type and Reduce Motion support • No account, no ads, no tracking. Camera images are never recorded or stored, and your readings stay on your device. A NOTE ON ACCURACY Readings depend on your device's sensors and how it's held. On iPhone Duo, iOS reports the hinge angle and decides how often it updates. Foldometer is a general measuring tool, not a medical or safety device.

Foldometer: Fold Angle Gauge on iPhone Duo: FAQ

Is Foldometer: Fold Angle Gauge optimized for iPhone Duo?

Yes. Foldometer: Fold Angle Gauge is Built for Duo: it uses the fold, Split View or the outer display. Verified on October 25, 2026 (App Store text).

What does Foldometer: Fold Angle Gauge look like on iPhone Duo?

Open iPhone Duo and Foldometer turns its hinge into a precision instrument. Watch the two halves move on screen as you open

How much does Foldometer: Fold Angle Gauge cost?

Foldometer: Fold Angle Gauge costs $0.99 on the App Store.

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