“A Rolex will never be as accurate as a cheap quartz watch.” That’s a commonly held belief by people who sniff at expensive automatic watches. Is it true? What about the reverse? Does more money buy you greater accuracy? Put on your best water resistant watch and join me for a data dive into the strange world of watch accuracy. . .
Casio Watch Accuracy
Depending on the model, Casio claims their battery powered watches achieve +/- 15 to 20 seconds accuracy per month. Using the best case of 15 seconds per month, Casios average 0.5 seconds per day (s/d).
The data above was gleaned from my personal collection. As you can see, my Casios exceed the manufacturer’s accuracy claim. My worst performing Casio: a vintage G-Shock G-7800 Super Square (below). It clocks-in at 0.48 s/d, right at the edge of Casio’s best case 15 seconds per month accuracy claim.
Rolex Watch Accuracy
Rolex uses their own accuracy testing protocol: the Superlative Chronometer Standard. A Rolex so labeled is guaranteed accurate to -2/+2 seconds per day. Over the course of 15 weeks, my Rollie beat the standard by a mile.
The Yachtmaster was accurate to -0.35 s/d, or about -10.5 seconds per month. Considering the fact that the Rolex is a purely mechanical watch (driven by a spring), losing a third of a second per day is truly remarkable.
Rolex vs. Casio Watch Accuracy
Paired against my five worst performing Casios, the Rolex is the more accurate watch. Geneva’s favorite son refutes the notion that “any quartz will keep better time than a Rolex.” The Rolex is also more accurate than my second worst Casio, a recent G-SHOCK model. OK, sure. All my OTHER Casios beat the Rolex. But not by much.
That done, let’s take a look at this from the price/accuracy perspective, asking the tough questions . . .
Mo’ Money = Mo’ Accuracy for Autos?
The following sample includes three automatic watches (’cause that’s how many I own). While it’s true that my most expensive watch is the most accurate, the differences between them are far from proportional.
The Lum-Tec 300-M3 ($795) is my least expensive auto. It’s powered by a pedestrian Miyota 9015 automatic movement. The Lum-Tec delivers an astonishing sub-second per day accuracy. It easily outperforms my COSC “Swiss Chronometer” Breitling.
Mo’ Money = Mo’ Accuracy for Quartz?
In my admittedly small and seemingly random sample, watch accuracy seems inversely correlated to price. The cheapest Casios in my collection are the most accurate. The leader of the pack: the venerable and vaunted Casio MDV-106 Duro.
Out of my three Duros, the best of the bunch clocks in at +0.11 s/d. That’s +3.3 seconds per month or +39.6 seconds per year. Less than a minute off PER YEAR. The Duro costs about $50 on Amazon (no commission on link).
My second most accurate Casio is also the cheapest. The $25 Casio “Royale” AE-1200WH averaged -0.12 s/d or 3.6 seconds per month accuracy, or 43.8 seconds per year.
My G-Shock GST-S300G is my most expensive non-atomic Casio. The $260 watch is accurate to +0.38 s/d, which is less accurate than my Rolex (see first chart).
This brief and not-particularly-scientific survey of watch accuracy didn’t include HAQ or thermo-compensated quartz watches, or a wide range of high end mechanical pieces (don’t get RF started on tourbillons). Even so, I think it’s safe to say there’s no direct correlation between watch price and watch accuracy.
Whether comparing mechanical to quartz, mechanical to mechanical, or quartz to quartz, your mileage may vary, regardless of the price paid. If accuracy is your thing, you can find your bliss at all price points.