2 responses

  1. Tom
    March 2, 2017

    I have just stumbled upon this page and thought it needed quite a bit of correction.

    First of all, the difference between ‘quartz’ and ‘chronometer’ (when used in relation to watches and clocks) is simply that ‘quartz’ is a type of timing technology whereas ‘chronometer’ is a certification standard.

    ‘Chronometer’ certification may be conferred upon a mechanical watch movement when it has been assessed as meeting ISO standard 3159. This equates, roughly, to -4/+6 seconds per day or -120/+180 seconds per month. Even the cheapest quartz watch will be spec’d to no worse than +/-30 seconds per month, which means quartz watches will always be more accurate than even the tightest-spec’d mechanical chronometer.

    Further, quartz watches may also have ‘chronometer’ status conferred upon them. Whilst there is no ISO standard for quartz chronometer status, the Contrôle Officiel Suisse des Chronomètres (COSC), which conducts the vast majority of chronometer certification tests, sets the standard for a quartz chronometer at approximately +/-25 seconds per year (or approximately +/-0.07 seconds per day).

    COSC certification of a watch movement does add a bit to the cost of producing a chronometer, but plenty of certified chronometer watches can be bought for around $500-1,500, including watches from brands such as Tissot, Christopher Ward, Mido and Stowa. At these prices chronometer watches are cheaper than the myriad non-chronometer-certified watches from luxury brands (including luxury quartz watches), which can sell for tens of thousands (or even hundreds of thousands) of dollars.

    Finally, having chronometer status does not mean that a watch is the most accurate around, or that another watch that hasn’t got chronometer status will necessarily be less accurate. COSC (which, as mentioned above, is the world’s primary tester and certifier of chronometer watch movements) will accept for testing only those watch movements which have been made in Switzerland. This means that movements made in Austria, Germany, England, Japan, China, the U.S. or elsewhere typically cannot be put forward for chronometer testing. Taking Japan as just one example, Grand Seiko’s in-house standard for their top movements is -2/+4 seconds per day, which is significantly superior to the ISO 3159 standard of -4/+6 and yet they cannot bear the label ‘chronometer’.

    Reply

  2. Koh Tony
    January 2, 2022

    From my experience I do not find my chronometer watch to be more accurate than my quartz watches.

    In fact, I have a few quartz watches and they are more accurate than my chronometer watch.

    Reply

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