Free online timegrapher or iPhone app?
A browser tool removes the install and price. A native app can control more of the audio session and preserve a repeatable measurement workflow. A bench machine still wins when the pickup and holder must be controlled.
Short answer: use a free online timegrapher for a quick, zero-install check. Use a native app when you need repeated runs, positions, history, or a report. Use a dedicated machine for regulation and repair.
Disclosure and method: this guide is published by Hairspring's developer. It compares workflows and documented audio controls, not measured accuracy. Browser examples and platform documentation were checked August 28, 2026. Features can change.
At-a-glance choice
| Option | Friction | Audio path | Evidence after the run | Best fit |
|---|---|---|---|---|
| Free browser timegrapher | Open a secure page and grant microphone permission | Browser media capture; supported processing controls vary by browser and hardware | Varies by site; often a live result without durable history | A fast check before installing or buying anything |
| Native iPhone app | Install; may be free or paid and requires compatible iOS | App-selected iOS audio-session mode and native capture pipeline | Can include history, repeated-run comparisons, position sessions, and exports | Measurements you expect to repeat, compare, or keep |
| Dedicated bench machine | Separate hardware and a stable work area | Contact pickup and purpose-built holder | Immediate instrument display; storage depends on model | Regulation, repair, and controlled workshop work |
The first difference is the microphone pipeline
A browser requests microphone access through getUserMedia().
The web platform exposes constraints for automatic gain control, noise
suppression, echo cancellation, sample rate, and other settings, but
support and available values depend on the browser and device.
A browser can ignore a non-mandatory constraint it does not understand.
That is not merely theoretical. Isochron's own free online timegrapher says browser microphones can apply processing it cannot fully disable and presents its web tool as a quick estimate. This is a useful, unusually clear limitation to look for when evaluating any browser measurement page.
A native iPhone app can configure an audio session for measurement. Apple's
AVAudioSession measurement mode
is designed to minimize system-supplied signal processing. Hairspring uses that
mode. “Minimize” does not mean a phone microphone becomes a calibrated contact
pickup, and it does not prove that one app is accurate. It does make the capture
configuration a deliberate part of the instrument.
The second difference is what happens after one number
A quick browser result answers “what does this setup show right now?” That can be enough to screen a watch that is obviously fast or slow. The harder question is whether the result repeats after the detector starts over.
Hairspring makes the second run part of the workflow. It reports each rate's statistical fit uncertainty, asks you to measure the same setup again, and saves whether the two estimates agree. It also keeps position runs, history, comparisons, and PDF measurement receipts on the device. A signal that cannot support a defensible result produces a reasoned refusal.
You can test repeatability without buying Hairspring. Record two rate readings and any uncertainty each tool provides, then use the free timegrapher repeatability calculator. Agreement shows repeatability under those conditions; it does not establish calibration against a bench instrument.
When each option makes sense
Use a browser tool when speed and zero cost matter most
You want a rough check, do not want to install an app, and are willing to repeat the run before interpreting a small difference. Confirm that the site states whether audio stays local, what it reports, and what limitations it acknowledges.
Use a native app when the measurement is a record
You want the same capture configuration across sessions, saved results, position labels, repeated-run evidence, or a report you can compare later. The App Store still deserves the same scrutiny: check price, privacy, compatibility, and whether the app withholds unsupported readings.
Use a bench machine when you intend to adjust the watch
A purpose-built contact pickup and holder reduce variation that a phone on a desk cannot eliminate. The phone vs WeiShi comparison protocol shows how to repeat each setup before comparing their results.
A fair browser-versus-app test
- Wind the watch consistently and choose one named position.
- Keep the room, surface, watch placement, and run length unchanged.
- Run the browser tool twice. Stop if its own two results do not repeat.
- Run the native app twice without changing the setup. Stop if those do not repeat.
- Compare rate only after both pairs repeat. Treat beat error and especially amplitude as separate questions.
- Record the browser, device, selected BPH, lift angle, position, and state of wind.
A matching browser and app result on one watch is useful evidence for that setup. It is not a general calibration. A stable disagreement may come from audio processing, pickup geometry, event detection, BPH selection, or a setting; repetition alone does not identify which tool is closer to a trusted reference.
Examples of current free browser tools
These examples show how varied the category already is. Inclusion is not an accuracy endorsement.
- timegrapher.ai states that it runs locally without an account and reports rate, beat error, amplitude, and BPH.
- Isochron's online timegrapher reports rate, BPH, and beat error and explicitly distinguishes its browser quick check from its native app.
- Online Timegrapher labels itself beta and exposes lift-angle selection alongside rate, beat error, and amplitude.
- timegrapher.watch offers a no-download, no-account microphone measurement page.
Try the repeatable native workflow
Hairspring is a native iPhone timegrapher built around the second measurement. It uses iOS measurement audio mode, keeps evidence locally, and states when the signal does not support a number.
One $9.99 purchase. No subscription, in-app purchase, account, ads, analytics, or automatic uploads.
Frequently asked questions
Is a free online timegrapher accurate?
One result cannot establish that. A browser tool can be useful for a quick check, but repeat the same setup and treat unstable or unsupported readings as inconclusive.
Does a browser process microphone audio?
It can. Browsers expose processing constraints, but availability and behavior depend on the user agent and hardware. A page should request the controls it needs and state the remaining limitation.
When is a native iPhone app the better choice?
Choose a native app when you need repeatability, saved history, position labels, consistent audio-session configuration, or an exportable record.
Can a browser or iPhone app replace a bench timegrapher?
They are useful for portable checks and repeated comparisons. Use a dedicated contact pickup and stable holder when regulation, repair, or a tightly controlled setup matters.
Primary sources
- Apple: AVAudioSession measurement mode
- MDN: media capture capabilities, constraints, and settings
- MDN: automatic-gain-control constraint and compatibility
- Isochron: online timegrapher and browser-processing disclosure
Hairspring is not affiliated with the browser tools named on this page. Product names identify examples in the current category. Corrections are welcome at moganes@gmail.com.