Goniometer: Joint ROM
Range of Motion Angle Meter
Only for iPhone
Free · Designed for iPhone. Not verified for macOS.
iPhone
New: a guided 3-step measurement. Set the start, move and hold — the end marks itself. Results are saved to Progress with left/right comparison.
Measure joint range of motion in degrees with your phone. Goniometer turns the phone's motion sensor into a digital goniometer for knee, elbow, shoulder, hip, ankle, wrist and neck flexion — at home, at the gym or during rehab.
HOW A MEASUREMENT WORKS
1. Pick the joint. A placement line tells you where the phone goes: flat on the limb, long edge along it, screen facing out.
2. Hold the start position still and tap Set start. That position becomes 0°.
3. Move to the end of the motion and hold still. After about three seconds the end is marked automatically — a ring fills while you hold and a haptic confirms the mark. You can also tap Mark end at any time.
4. Check the number and tap Save. The recorded range is the largest marked angle minus the smallest, including the start.
The app waits for a steady reading before it lets you set the start or mark an end, so a fast swing is not recorded half-way. If the phone is placed on its side, where the angle cannot be read reliably, it asks you to reposition instead of showing a wrong number. Sweeps past 180° keep counting instead of wrapping around.
WHAT YOU GET
• Live angle from your start position, on a clear dial with 45° marks.
• Automatic end marking plus a manual Mark end button.
• Eight motions: knee, elbow, shoulder, hip and neck flexion, wrist flexion and extension, and the ankle (dorsiflexion and plantarflexion together).
• Your result as a percentage of the AAOS reference range, with the published source one tap away.
• Left and right tags, with the difference to your latest measurement on the other side.
• Progress tab: every saved measurement per joint with latest, largest and record count.
• CSV export of your history, and a simple 0–10 pain log.
• A reference table and a step-by-step guide with accuracy tips.
WHO IT'S FOR
People following a rehab or stretching plan who want to see their range change over weeks, trainers and coaches checking mobility, and anyone curious how far a joint moves.
GOOD TO KNOW
The app measures movement in a vertical plane; keep the other body segment still. Readings depend on phone placement and case. Goniometer is not a medical device and does not diagnose, treat or prevent any condition. Talk to a healthcare professional about your results.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Measuring is now a guided 3-step flow: set the start, move and hold until the end marks itself, then save. The app waits for a steady reading, refuses a sideways phone, and keeps counting past 180°. Results show the percentage of the AAOS reference range with its source, plus left/right difference.
The developer, heekyung moon, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Used to Track You
The following data may be used to track you across apps and websites owned by other companies:
- Identifiers
- Usage Data
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Identifiers
- Usage Data
- Diagnostics
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- heekyung moon
- Size
- 51.4 MB
- Category
- Utilities
- Compatibility
Requires iOS 16.4 or later.
- iPhone
Requires iOS 16.4 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
18+
- 18+
- Contains
Advertising
- Copyright
- © 2026 Moon