Device Monitor: frequently asked questions

No account needed, and most of it runs offline too: device info, the dashboard and every sensor test just read the device itself. The internet only gets used by ads in the free version, by App Store purchases and restores, and by the Latency Test, which times requests to a server.

Whatever iOS is willing to hand over: level and compass angles, air pressure and relative altitude, acceleration, microphone input level, a relative brightness reading from the front camera, charge level, storage, memory and connection type. Battery health and charge cycles are off limits because iOS doesn't expose them to apps. Brightness comes out as a percentage, not lux. Gyroscope and magnetometer screens are Pro.

Not from an App Store app, no. iOS keeps maximum capacity and cycle count for itself, so Device Monitor can only show charge percentage and whether it's charging. The remaining-time line on the battery card is a rough rule of thumb, nothing more - for the real number, go to Settings > Battery > Battery Health (Battery Health & Charging on some versions).

Honestly, not much. iOS already frees memory on its own the moment an app needs it. The Clear RAM button briefly fills about 320 MB and releases it, then shows how far the used figure dropped - which can push whatever you had open out of memory, so it reloads from scratch next time. It will not make the phone faster.

No. RAM only holds what's running right now; photos, messages and files sit in storage and are never touched. The worst that happens is a backgrounded app restarting instead of resuming where you left it.

No - iOS won't show apps system-wide CPU use or a per-app breakdown, so the CPU Usage figure you see is Device Monitor's own work, nothing else's. It's a live graph of the app itself, not a way to catch whatever is draining your battery.

No app can, and that includes this one. The Pro Device Integrity Check only confirms iOS reports the motion, pressure, proximity and magnetic sensors as present; its certificate proves nothing about liquid contact. The actual liquid contact indicators are inside the phone, and only a technician can look at those.

It changes no system settings, full stop. There are buttons that look like optimisers - Clear RAM, and Pro cards with battery tips and storage cleanup suggestions - but those are the same fixed advice for every phone, and the buttons don't change anything. Read them, don't expect them to clean anything.

The Decibel Meter is Pro, and it's uncalibrated: microphone level plus a fixed offset, no A-weighting. Fine for comparing one room with another or noticing a noise got louder; not fine for a legal or workplace measurement.

It's real in the sense that it uses the magnetometer - same sensor as the compass - and genuinely reacts to iron, steel, magnets and electronics a few centimetres from the top of the phone. It will not find gold, silver, copper or aluminium, and it is not a stud or cable finder. Part of Pro.

The angles come straight from the phone's motion sensors, shown to one decimal of a degree. It says LEVEL ✓ once both tilt angles sit within about 1.1°. There's no calibration built in, so a case or a camera bump can tilt the reading - for actual building work, use a real spirit level.

No. Both of those cards are simulated, not measured. The one real network number here is the Latency Test, which times 10 HTTPS requests to a host you choose. For download and upload speed, you want a dedicated speed test app.

Two tools need it: the Digital Compass, for true north, and the GPS Accuracy Test, which reads one position fix. The position only ever shows on screen - it's not stored or sent anywhere, and you can decline and still use every other test.

The Light Meter reads brightness from the front camera image - no photo taken, nothing saved. The Microphone Test needs the mic to show input level; the audio goes to a temporary file that is never played back, kept, or uploaded.

No. It checks whether the screen, speaker, microphone and sensors respond, nothing about parts history or account locks. On recent iOS versions part history lives in Settings > General > About, and Activation Lock has to be checked by watching the seller sign out of their Apple Account in front of you.

Not in degrees, no. iOS only gives apps a thermal state - Normal, Elevated, Serious or Critical - and that's exactly what the Thermal State row shows. There is no temperature sensor reading happening anywhere in the app.

Free to download, with ads. The tests most people actually use - dead pixels, speaker, microphone, level, compass, barometer, proximity, GPS, Bluetooth, keyboard, device info, PDF export - cost nothing. Pro removes the ads and adds things like the decibel meter, metal detector, gyroscope, pedometer and the Face ID / Touch ID test.

Open Settings in the app. Manage Subscription hands you off to Apple's own subscription sheet to change or cancel the plan, and Restore Purchases brings Pro back on a new or reset device signed into the same Apple Account.

No - iPhone and iPad only. Nothing syncs between devices, and results don't survive you closing the test.