Are Automatic Watches Accurate?

How Accurate Is Automatic Watch

Automatic watches are outstanding inventions. Hundreds of combinations of minuscule parts such as gears, springs, screws etc. work together to produce a timekeeping device. Since it’s all mechanical moving parts, there is no way that it can be totally accurate. Are automatic watches accurate then? How accurate is automatic watch? The relevance of these questions varies between people. Some people can live with a not so accurate watch, as long as it’s automatic and looks great while there are people that really obsess with accuracy and need their watches to be really accurate.

A general rule of thumb that I’ve taken for accuracy of automatic watches is +-25 seconds per day. This means the watch should only gain or lose 25 seconds between two days. This is actually consistent with most watch manufacturers published accuracy of their movements. So if your watch is gaining or losing more than 25 seconds per day, get it checked! That could mean some serious problems with your watch.

This accuracy is only for normal automatic watches and its fairly accurate (25 seconds/ 86,400 seconds in a day = 0.03% inaccuracy. So about 99.97% accurate). But there are those who seek the perfect accuracy either due to work (divers, military personnel, etc.) or for self pleasure. For those people, a Chronometer watch is most suitable. Chronometer is a watch with almost perfect accuracy (-4 or +6 seconds per day).

Are Automatic Watches Accurate?

A Breitling NavitimerChronometer

Automatic Watch Accuracy Standard

Chronometer is a name to indicate that a watch has been tested and certified to be a truly accurate timepiece based on some standards. Generally, automatic watch accuracy standard is referred to the COSC (Contrôle Officiel Suisse des Chronomètres) and the ISO 3159 standard. Japan companies also has their own accuracy standards with Seiko (the Grand Seiko line of watch) and Citizen have their in-house testing. Here, I will only explain on COSC/ISO standards as the Japan’s standard is more or less the same as the COSC.

Contrôle Officiel Suisse des Chronomètres aka COSC is a non-profit organization set up to measure, test and certify accuracy of watches. Watches that are certified are granted “Chronometer” status – the highest prestige a watch can have. It is a mark that means the watch is of highest accuracy among the millions of automatic watches in the world, a symbol of pride for the owner of the watch. I should also clarify that “Chronometer” is not the same as “Chronograph”. Chronograph is a function in watches (automatic and quartz alike) that can function as a stop watch.

The testing of COSC is based on ISO 3159. All Chronometers will have a unique serial number from COSC and is typically engraved on the watch. The movement is tested for 16 days, whereby 15 measurements are taken after each day. It is then put in different positions (horizontal face up, face down, vertical etc.) and subjected to different temperatures (8, 23 and 38 degrees celcius). The movement then is judged according to 7 criteria in which it has to pass all. The COSC Chronometer testing criteria and its permissible (maximum) variations in timekeeping are below:


COSC Chronometer Testing Criteria:

1. Average Daily Rate: -4 or +6 seconds/day
2. Mean Variation In Rates: 2 seconds/day
3. Greatest Variation In Rates: 5 seconds/day
4. Difference Between Rates In Horizontal And Vertical Positions: -6 or +8 seconds/day
5. Largest Variations In Rates: 10 seconds/day
6. Thermal Variation: +-0.6 seconds/degrees celcius
7. Rate Resumption: +-5

From what we can conclude from the criteria above, a Chronometer should be accurate and consistent in its timekeeping. It must also be able to be accurate at different temperatures. Since gravity plays a role in accuracy of movement’s parts, a Chronometer should be able to be accurate at any position either horizontal (watch face up or down – as in when you take it off at night) and vertical (when you are wearing your watch).

Only about 3% of Swiss watches are certified Chronometers and most of them are very expensive and costs thousands (think your usual Rolex, Breitling, Tag Heuer and Omega). This is because it is very expensive to manufacture a Chronometer movement as the parts need to be of the highest quality. It also need to be assembled by hand and sent to testing. This all adds up to the cost of the watch. Now you know why that Rolex will cost you at least $5000.

I would like to add that a non-certified watch can also have a Chronometer like accuracy. Movements such as ETA 2892A2 (in Hamilton Intra Matic), ETA 2824-2 (in Tissot Le Locle), Seiko’s Cal. 6R15 (in Seiko SARB065) and Citizen’s Cal. 9010 (in Citizen Signature Grand Classic) are reported to have Chronometer-like accuracy in normal condition. Bear in mind the COSC testing standard is quite rigorous encompassing various positions and temperatures. A non-certified fine movements listed above can achieve the -4+6 seconds/day accuracy in normal usage conditions just fine, as long as the owner take care of them well. No need to pay those thousands of dollars then eh?

Are Automatic Watches Accurate?

Rolex GMT Master II,  certified Chronometer. Rolex holds the record as the most COSC certified Chronometer movements.

Factors Affecting Automatic Watches Accuracy

There are a few factors that can affect the accuracy of automatic watches. Some of the major factors that I believe are important for all automatic watch owners to know are:

1- Temperature
Using your watch in environments that are too cold (less than 8 degrees celcius) or too hot (around 38 degrees celcius) can really affect your watch accuracy. This happens because when it’s too hot (hotter than normal room temperature) metal parts inside the watch will expand, and when its too cold, the metals will contract. The expansion and contraction is not much, perhaps only a few millimeters that you can’t detect with you own eyes. But even that is enough to disrupt most of automatic watch’s movements from functioning properly. As a rule of thumb, your watch will lose time in hotter weather, and will gain time in cooler temperatures.

2- Magnetism
Watches are also sensitive to magnetism. They are steels parts remember? Any magnetic objects as well as electronic objects that can become magnetic such as phones, PC, television etc. should be avoided of any direct contact with your watch.

3- Shock
Any shock to the watch may also damage or move some of the internal parts. Your watch might be able to run like normal after that big fall on the ground but it might not be as accurate anymore.

4- Manual Winding For Full Mainspring Energy Reserve
Automatic watches are meant to be used without any manual winding for it to function properly. Yes it is functioning properly but how about its accuracy? Most automatic watches (based on my watches and some reviews I’ve read) would become very terrible at timekeeping accuracy if you don’t wind it manually (by rotating the crown). You can read a blog by here <<LINK that shows how even a Breitling (certified Chronometer) will have bad accuracy if not wound manually.

5- Interval Service

It is recommended to have interval servicing for your watch to examine it, oiling and cleaning of its internal parts. The service interval vary between manufacturers. For example, Seiko recommends for 3 years, while Tissot recommends 4-5 years. This will depend on the exact model though.


It is very important to know that our automatic watches are very delicate and need proper care for it to function properly and keep accurate time. Please remember these tips well next time you want to throw your Tissot PRS 516 carelessly into your table.


What Is The Most Accurate Automatic Watch?

That’s a very tough question. For me, the Chronometer certified watches are all very accurate. It’s very tough to find a watch that can rival those slim tolerance levels. Though some would say the Japanese standards are stricter, but it’s definitely very hard to say that with certainty. For me, it is important to know that we have to live with this inaccuracy in timekeeping as that is part of the charm of automatic watches. If you want higher accuracy, buy a Quartz then =p.



I hope you have learnt a lot from my post here. Do keep in mind on the factors that affect your watch’s accuracy. Those are very important things to remember. If you have any thoughts, please drop your comments below. Till next time then. Cheers!


Hamilton Intra Matic H38455131 Automatic Dress Watch – Gorgeous American Classic

Hamilton Intra Matic H38455131 Automatic Dress Watch - Gorgeous American Classic

Hamilton Intra Matic is Hamilton’s classic line of watch, designed by taking the cues of the American brand’s vintage dress watch models. They are really popular in the 1960s for quality watches that rivaled even the Swiss. Just like the Hamilton Khaki King this watch is a homage to their American heritage, specifically their vintage dress watches.

Side by side comparison of the Hamilton Vintage (top pic) and the new Hamilton Intra Matic (bottom pic). Timeless beauty is the word here. The design works in the 1960s, and it still looks gorgeous in this time and age.

Hamilton Intra Matic Specification

Diameter: 38 mm or 42 mm
Thickness: 10 mm
Lug to lug width: 48 mm
Lug width: 20 mm
Weight: 50 grams
Case: Polished stainless steel
Dial: Black dial
Dial Window: Sapphire Crystal with dome shape
Band: 20 mm width multi-link polished stainless steel bracelet with butterfly clasp.
Water Resistance: 50m / 164 ft
Movement: Swiss ETA 2892A2
Movement Features: 21 Jewels, 42 hours power reserve, +-20 seconds maximum daily variation (average of +-5 seconds per day)
Other Features: Crown at 3 o’clock, exhibition caseback, decorated movement, date display at 6 o’clock, Swiss Made
Best Place To Buy:


5 different designs were produced. Each of them is offered in 2 sizes : 38 mm and 42 mm case diameter


Hamilton produced 10 different Intra Matic models (shown above or you can view it all at Hamilton’s website here).

The models are similar, but with different combinations of dial color (black or silver), band type (stainless steel multi-link bracelet or leather band), casing diameter (38 mm or 42 mm) and casing color (polished stainless steel or gold coated stainless steel).

Everything else (dial design, the venerable ETA 2892A2 movement) is the same for all the models. The watch I’m reviewing in this article is the 38 mm diameter, black dial with bracelet version (because this is the one I fancy the most =) and it’s serial number is H38455131.

But as I said earlier, the other watches are basically the same with this one and this review should be able to cover all of them.


Hamilton American Classic Watches – Gorgeous Slim Profile

American Classic is the other name of the Intra Matic line and I explains itself. The watches are designed as a tribute to the vintage Hamilton dress watches. The dial with the stick markers and slim hands are reminiscent of their old watches.

Even the Hamilton signature and logo is the same as their vintage ones. This is a vintage Hamilton watch out the outside, but with modern parts and manufacturing processes to give you the best of both worlds.

The watch is produced in 2 diameter, 38 mm and 42 mm. I would definitely take the 38 mm as my wrist is quite small but for those that have a bigger wrist, you can always get the bigger version, albeit at a higher price than the 38 mm.

The one thing I really like about this watch is the slim profile, at 9.5 mm thick thanks to its slim ETA 2892A2 movement (more on that later).

Coupled with the overall slim case design, and the dome shaped dial window, the watch is very sleek and looks as elegant as what you would want from a dress watch. At just 50 gram, this could be the lightest watch you ever use.

The dial is black in color, and has stick markers. A date display is located at 6 o’clock, a very refreshing and unique design as it is very different than today’s common date at 3 o’clock design.

The Hamilton signature and logo is located at the center top of the watch and featuring Hamilton’s old logo and signature. The dial window is made from sapphire crystal and shaped to be like a dome.

The polished stainless steel case is also designed to be curvy at the edges, creating a round shape all over the watch which is very beautiful to look at.

Hamilton Intra Matic H38455131 Automatic Dress Watch - Gorgeous American Classic

Beautiful Multi-Link Bracelet

The bracelet of the Hamilton Intra Matic is a true art in itself. The bracelet is constructed from multi links instead of the traditional one piece link in many bracelets.

The multi link bracelet’s polished stainless steel create a beautiful and reflective effect, catching lights from different angles. It’s just truly amazing to look at and beautifully complement the handsome watch.

The clasp is butterfly clasp with push button, same as the Tissot PRS 516. Because of this, it would be quite hard to adjust the bracelet perfectly to your hand because of the absence of adjustment slots in the clasp.

But if you are not a bracelet type guy, there is also models of the Hamilton Intra Matic with leather bands that looks as stunning.


Swiss ETA 2892A2 Movement – High Quality Movement In A Middle Range Watch

Inside the Hamilton Intra Matic automatic watch, is the Swiss ETA Caliber 2892A2 movement. If you noticed, the movement is different than other typical Swatch Group low-middle range watches that uses ETA 2824-2 and 2834-2 (day and date) movement family (such as the Tissot Le Locle and Hamilton Khaki King).

The ETA 2892A2 is an improved version of the 2824-2, in which it has a slimmer profile, smaller diameter to be able to fit with lots of watches, newer technology and more accurate.

The result: a higher quality movement that is said to be on par with Rolex’s own movement and typically equipped in higher end brands such as Breitling and IWC.

And that is what makes the Hamilton Intra Matic a true bargain for automatic watch lovers. The 2892A2 in a middle range watch is just unthinkable of.

The slim profile of this movement is what enabled the watch to get its slim profile. One thing that I really don’t like is the absence of seconds hand (you would need some time to notice it from the photos and videos).

Hamilton opted not to put any seconds hand in this watch, which is not a really good decision. For me, a seconds hand is what will give automatic watches its characteristic sweeping motion. Not to mention you cannot set the watch to the exact time if there is no seconds hand.

It is truly a foresight by Hamilton in this part. I really hope they reconsider this and re-release another Intra Matic model with seconds hand =)

Hamilton Intra Matic H38455131 Automatic Dress Watch - Gorgeous American Classic

The watch also has an exhibition caseback – a standard of some sort for dress watches. Through the caseback, you can see the back of the ETA 2892A2 movement.

It has been decorated beautifully. The rotor got Hamilton signature engraved on it, and is very well executed. The watch also is rated to have 50 m or 164 feet water resistance for your peace of mind.



Hamilton Intra Matic is a very beautiful dress watch, with timeless dial design that is just classy and elegance to wear and look at.

The slim profile, dome sapphire crystal dial window and the case’s curvature all make the watch slimmer than it is and looks sleek. Inside the watch is the venerable Swiss ETA 2892A2, ETA’s higher range of movement.

The multi link bracelet is so amazing and really goes well with the watch. This is definitely a catch for a watch below $600.



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