AngleDuo vs Angle Gauge
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
AngleDuo
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Two surfaces. One angle. On iPhone Duo, AngleDuo uses the hinge to measure the angle between two surfaces. Position the two halves against the surfaces and read the result. Hold the value with a tap or enable automatic capture, which waits for two seconds of stable readings. A held value stays available when you close the phone. On other iPhones and iPads, measure two surfaces in sequence: capture the first, then move the same device edge to the second. The shared edge must be horizontal; this gravity-based method cannot measure a corner between vertical walls. On Duo, sequential measurement is available in Settings. The level measures with the device resting on its back or standing on an edge. A moving shadow and a fixed scale show the tilt. Placement can be selected in Settings, where you can also find slope and roof-pitch values. “Per cut” gives the saw setting for two equal miter cuts. An interior angle of 112° gives 34° per cut; 0° means a square cut. Find it on Duo’s supplementary inner pane or in Settings. The spirit level is free. The angle finder includes 5 free measurements; after that, the one-time AngleDuo Pro purchase unlocks it without limit. Measure angles without limit, with the hinge and on any iPhone. Also includes target angles with tolerance and relative zero. Optional Pro purchases and restoration are handled by Apple through StoreKit. The app checks the purchase entitlement on your device. We do not receive your payment details. The number of free angle measurements used is counted on your device in the Keychain; it is not transmitted and is not reset by deleting local data. Deleting local measurements does not cancel a purchase.
Angle Gauge
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Angle Gauge turns the hinge of iPhone Duo into a precision protractor. Set the phone into a corner, against two surfaces or across a joint, and read the angle to a tenth of a degree. MEASURE • Live angle to 0.1°, on the inside display or the outside one • Hold, Auto-Hold when the reading settles, and Zero Here for relative angles • Supplement, bisect and miter angle for every reading • Snap to 1°, 5°, 15° or your own step TARGET • Pick 45°, 90° or any angle with presets and a fine stepper • Haptics build as you get close, then click when you arrive • Tolerance from ±2° down to ±0.25° MATCH • Capture angles into a named library • Find them again later, by feel LEVEL • Bubble level when the phone lies flat, line level on its edge • Two-step calibration cancels the camera bump and the slope of your table • On iPhone Duo, read the hinge relative to true level ON EVERY IPHONE The level works on any iPhone. Measure, Target and Match read the hinge, so they need iPhone Duo with iOS 27.1 or later. BUILT LIKE AN INSTRUMENT • Two-point hinge calibration against fully closed and flat • Degrees, radians or percent open • VoiceOver, Reduce Motion, light and dark • No accounts, no ads, no tracking, and it never goes online
Screenshots
Verdict
The clearest difference is in-app purchases: Angle Gauge at none against AngleDuo's 1. AngleDuo's advantage is iOS requirement (17.0 vs 27.0). On price, ads and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. AngleDuo sells 1 one-off in-app purchase. Angle Gauge asks for nothing beyond the download.
| Parameter | AngleDuo | Angle Gauge |
|---|---|---|
| Price | Free | Free |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Devices | iPhone, iPad — better | iPhone |
| Requires iOS | 17.0 — better | 27.0 |
| Further details — not scored | ||
| Size | 4 MB | 1 MB |
| Age rating | 4+ | 4+ |
| Developer | Julian Zefferer | Jared Kaeb |
In-app purchases
AngleDuo
- AngleDuo Pro$3.99
Angle Gauge
No in-app purchases









