Watt Charging Speed vs LagMeter
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Watt Charging Speed
Monitor your device's charging speed in real-time watts. Compare chargers, track charging history, and estimate time to full charge. This app is private by design, with no ads or tracking.
- Real-time wattage display
- Color-coded speed indicator
- Estimated time to full charge
- Benchmark different chargers
- Charging history tracking
- Offline functionality
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How fast is your charger? Plug in your iPhone or iPad and Watt Charging Speed estimates your charging speed in watts: the power reaching your battery. Tell a fast charger from a slow one, and see whether your cable keeps up. HOW IT WORKS, HONESTLY iPhone and iPad don't let apps read the charging power from the hardware. Watt works out the charging speed from how quickly your battery percentage rises, combined with your device's battery capacity. That means: • The figure is an estimate of the watts reaching the battery. That is less than the charger's rated output: a 20 W charger usually reads below 20 W, and that is expected • iOS reports the battery level in steps, so the first reading can take up to about 10% of charging. After that, the figure follows your charge • The longer a session runs, the steadier the estimate • If Watt doesn't know your device's battery capacity, it says so and uses a typical value WHAT YOU SEE • A watt estimate while you charge • Color-coded speed labels: Fast Charging, Charging, Slow Charging and Trickle Charge • A charging ring and a graph of the session • Estimated time until fully charged • A notice when charging seems to have paused, for example with Optimized Battery Charging COMPARE CHARGERS AND CABLES • Create benchmark tests for a battery range (for example 30% → 80%) and run one with each charger or cable • Compare the results for the same range • See which charger or cable performs best CHARGING HISTORY • Sessions are saved automatically with average watts, duration and battery range • Label each session with the charger you used • Compare sessions over time to spot a slow cable or an aging charger MADE FOR YOUR DEVICE • Has the battery size of every iPhone and iPad that runs iOS 18.6: from iPhone XS to iPhone 18 Pro Max and iPhone Duo, and from older iPads to the latest iPad Pro (M5) • On a few iPhone Pro models Watt asks once whether your iPhone has a SIM card tray, because the battery differs slightly. You can change the answer in Settings • On iPad and an open iPhone Duo, the charging ring and status stay on screen while you switch between Details and Benchmark PRIVATE, ONE PRICE • Pay once: no subscription, no ads, no account • No tracking. All data stays on your device • Works offline FEEDBACK Something looks off, or you have an idea? Tap Send Feedback in Settings or in How It Works. It opens an email with your app version, iOS version and device model filled in. GOOD TO KNOW iOS pauses apps in the background, so keep Watt Charging Speed open while it follows your charge. It keeps the screen awake during a session so nothing is interrupted. Perfect for testing a new charger, finding out why charging feels slow, or settling which of your cables belongs in the drawer.
LagMeter
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LagMeter measures audio latency from output to mic. Play a test sound through your selected audio output, capture it with your iPhone microphone, and see the latency in milliseconds. Use it to compare speakers, soundbars, wired audio, Bluetooth, AirPlay, USB audio devices, and other playback routes. LagMeter is designed for quick, practical latency checks in gaming setups, home theater systems, audio experiments, and everyday listening environments. Note: Measurements include the full observed audio path, including output, device processing, speaker sound, air travel, microphone input, and iOS audio processing. Results are most useful for comparing setups under the same conditions.
Screenshots
Verdict
The clearest difference is chart position: Watt Charging Speed at #179 against LagMeter's unranked. LagMeter's advantage is price ($0.99 vs $1.99) and iOS requirement (16.0 vs 18.6). On ads, in-app purchases 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
Watt Charging Speed costs $1.99 and LagMeter $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.
| Parameter | Watt Charging Speed | LagMeter |
|---|---|---|
| Price | $1.99 | $0.99 — better |
| Rating | 4.2 (13 ratings) — better | — |
| Positive reviews | 20.0% of reviews | — |
| Number of ratings | 13 — better | — |
| Update frequency | Every 3 weeks | — |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | — |
| Best chart rank | #179 — better | — |
| Devices | iPhone, iPad — better | iPhone |
| Requires iOS | 18.6 | 16.0 — better |
| Further details — not scored | ||
| Size | 3 MB | 2 MB |
| Age rating | 4+ | 4+ |
| Developer | Sindre Sørensen | Naoya Sato |
In-app purchases
Watt Charging Speed
No in-app purchases
LagMeter
No in-app purchases









