Chronographer vs Baseline OBD
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Chronographer
This app helps you meticulously track the accuracy of your mechanical watches. It records time differences, calculates detailed performance metrics, and visualizes trends with charts and histograms. You can also manage your watch collection, log daily wear, and analyze positional variations.
- Track mechanical watch accuracy
- Calculate detailed performance metrics
- Visualize accuracy with charts and histograms
- Manage watch collection with notes and photos
- Log daily watch wear
- Analyze positional variation
- Export watch data
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Chronographer is for people who enjoy mechanical watches. It does two things: 1. Tracks your watches’ long-term accuracy 2. Records wrist time Chronographer can work with your whole watch collection. Create a “card” for each watch, giving it a name and, optionally, a longer description. Select a picture from your Photos library and add additional notes, such as the watch’s specifications, purchase details, and service history. All information is stored in iCloud and automatically synchronized between your devices. To track a watch’s accuracy, periodically collect data points comparing its indicated time to the current correct time. Chronographer tracks offsets (the difference from the correct time) and daily rate (how many seconds it gains or loses per day). It uses this information to create graphs and histograms that help you visualize your watch’s performance over time. Chronographer also calculates the following metrics: * Average offset * Max. positive offset * Max. negative offset * Last offset * Net gain/loss * Best-fit rate * Average rate * Fastest rate * Slowest rate * Last rate * Rate variance * Best-fit rate drift You can log the watch (or watches) that you wear each day. Chronographer’s wrist time tracking feature lets you see which watches you wear the most and how long it’s been since you’ve worn each one. You can use Chronographer to identify positional variation. When you record a data point, include the position (dial up, crown up, etc.) that the watch was stored in. Then, you can restrict the charts and metrics to specific positions and compare the results. Chronographer includes a large digital clock to help when you set your watches. For more information, including a detailed user’s guide, see https://www.rmfrance.net/chronographer
Baseline OBD
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Baseline reads your car through a Bluetooth OBD-II adapter, keeps a record of every drive, and watches the margins on the car's own on-board tests, so a part that is wearing shows long before its warning light. Every drive, kept. Plug in the adapter once. From then on Baseline connects on its own when the car wakes up, takes a snapshot (identification, codes, freeze frame, on-board monitor results) and records the drive, even with the phone in your pocket. Margins, not just codes. A code is the cliff. Baseline shows the distance to it: the catalyst's own efficiency test, the oxygen sensor, fuel trim, warm-up rate, the 12 V battery at rest, and the engine's misfire counters per cylinder, polled every 30 seconds and timed against engine starts. Evidence you can hand over. A pending code and its freeze frame vanish at the end of the next clean drive. Baseline keeps them and exports an evidence packet: a PDF, CSV files and the raw records, with the readings exactly as the car reported them. Trend and crossing estimates, in beta. Once a test has enough drives, Baseline fits a line to your own car's readings and estimates when it would reach the limit. These estimates are labelled beta wherever they appear. Private by design. No account, no server, no tracking. Everything stays on your iPhone unless you export it. Works with - Cars sold in the United States from model year 2008 on (CAN OBD-II), and many 2004–2007 cars. - The OBDLink CX Bluetooth LE adapter. ELM327-based Bluetooth LE adapters (Vgate iCar Pro BLE, Veepeak OBDCheck BLE, vLinker BLE) should connect but are untested; Wi-Fi and classic Bluetooth adapters cannot be used by an iPhone app. Baseline reads only. It never writes to the car and never clears a code. It is not a substitute for a professional diagnosis: when your car's own warning light is on, have it looked at.
Screenshots
Verdict
Chronographer and Baseline OBD are too close to call on the numbers: across 5 compared parameters — price, ads, in-app purchases and device support among them — neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.
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. Neither carries in-app purchases, so what you see is what you pay.
| Parameter | Chronographer | Baseline OBD |
|---|---|---|
| Price | Free | Free |
| Rating | 3.4 (5 ratings) — better | — |
| Positive reviews | 50.0% of reviews | — |
| Number of ratings | 5 — better | — |
| Update frequency | Every 2 months | — |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone, iPad — better | iPhone |
| Requires iOS | 18.6 | 17.0 — better |
| Further details — not scored | ||
| Size | 3 MB | 3 MB |
| Age rating | 4+ | 4+ |
| Developer | Robert France | Alphonse Romero |
In-app purchases
Chronographer
No in-app purchases
Baseline OBD
No in-app purchases









