The Movement Clinic

Is your Tudor actually running fast?

Log a cumulative daily offset for at least 7 days (14 is better) and this tool reads the result the way the research says it should be read — which is not the way most owners read it.

Consistency beats accuracy

A watch that runs a steady +8 seconds a day is mechanically healthy and needs a five-minute adjustment. A watch that averages +2 but swings from −12 to +16 is sick. Most people would be delighted with the second one and worried about the first — that's backwards, and it's the single most common misreading of a rate test.

Set up the test

A single day of comparison is noise: temperature alone permits about plus-or-minus 0.6 s/d per degree Celsius under COSC, and wrist heat versus a cold nightstand is up to about 9 s/d of legitimate difference. Only a cumulative log over at least a week separates a real rate from measurement error.

Sync the watch once at time.is, then never reset it for the duration of the test.
Every 24 hours, shoot a 60fps video or a still photo with both the dial and the reference time display in frame, taken from directly overhead — parallax is the biggest source of bogus readings.
Log the cumulative offset from the original sync, not a daily reset to zero.
Run a minimum of 7 days; 14 is better.
If you can, run two campaigns: worn (real-world rate) and static on a nightstand (the movement's own rate).

The full protocol also suggests logging wind state and ambient temperature if you have them — this tool only asks for the three fields below, but noting the rest on paper alongside your photos never hurts.

This measures rate. It does not measure amplitude.

Phone-based amplitude readings are unreliable to the point of uselessness — watchmakers report the same app swinging 170°–310° on one unchanged movement, because a timegrapher needs a piezo pickup clamped to the case, not a phone microphone tuned for voice. This tool will never ask you to estimate amplitude, and you should be skeptical of any app that offers to.

What you can detect for free, without a timegrapher: the watch stops short of its rated power reserve, it runs fine dial-up but stops in a vertical position, it won't self-start after sitting, the seconds hand stutters or jumps backwards, or the rate changes sharply late in the reserve versus at full wind. Any of those is worth a watchmaker's look regardless of what your rate log below says.

This log lives only in this browser

Nothing is sent to a server and there's no account. Your entries are saved to this browser's local storage, which means clearing your browsing data, switching browsers, or switching devices ends the test. Export a CSV copy of your log (button below, once you've logged at least one day) so a cleared browser doesn't cost you the whole run.

Your tests

Track more than one watch by starting a separate test for each.

Name this test (optional)

Reference number or model name

This determines which spec your mean rate gets checked against. Not sure? Look up your movement first, then come back.

Log today's reading

Log the date the reading was actually taken, not the day you happen to be filling this form in. A missed day, or two readings on the same day, is fine — this tool reads the actual gaps between dates instead of assuming every entry is exactly one day apart.

Date

Cumulative offset (seconds)

Overnight position

Hours worn

The running total since you synced and hacked the watch — not a daily reset. If the watch is 6.4 seconds ahead of the reference today and it was 3.2 ahead yesterday, log 6.4, not 3.2.

Your log

Day	Date	Cumulative offset	Daily rate	Overnight	Hours worn

Further reading: “My Tudor Is Running Fast” — What's Actually Wrong (Usually Nothing)

The Movement Clinic is an independent publication by Timekeeper PH. It is not affiliated with, endorsed by, or connected to Tudor or the Rolex Group. This tool reads a log you provide — it cannot verify your readings, and it is not a substitute for a qualified watchmaker.