What is a Certified Chronometer and how accurate is it? - Watch and Learn #32

In today's episode of Watch and Learn, we will be discussing the world of COSC Certified Chronometers. The term chronometer is often used, but do you really know the true meaning and the testing involved to earn "chronometer" status? It's quite intricate and not just any movement can be a certified chronometer.
Please view our selection of wristwatches at: www.longislandwatch.com

[@imranchowdhury4972]

After watching for 5 years I finally found one video that explains accuracy and COSC issue most simpler. Lastly the Sinn accuracy surprised me astonishingly and totally changed my concept of accuracy. A big thanks Marc for this great video and your academic knowledge is far more impressive than any other watch guys in you tube. Long live and teach us more. Once again thanks and love from Bangladesh.

[@islandwatch]

Thanks so much for watching!

[@ennigmaa]

Your videos are so much more informative and to the point without any drama, dogs, animation and meaningless adjectives to describe the watch. You deserve far more subs.

[@islandwatch]

We will get there, thank you!

[@hectordemarchena4414]

Mark, that was a fantastic video. This series of yours should be required watching for anyone trying to get into the world of watches. Thank you for doing it! Hector

[@islandwatch]

Haha, thank you!

[@philrodriguez558]

I love your videos ! It is like having my own horology classes ! Thanks again !

[@islandwatch]

Thanks for watching!

[@Klizzix]

great work on all these videos, helping me to get started with automatic watches. much love from germany

[@islandwatch]

Thank you.

[@sarfarazshaikh771]

Again with a great informative video, really appreciate for giving the knowledge in the simplest form for a lay man understanding. Thanks mark n Keep it up.

[@islandwatch]

thanks.

[@True-os6tg]

Great stuff .Up until a few weeks ago I'd stopped wearing watches completely and had zero interest Then I decided to look into a new dive watch and entered a rabbit hole that dont ever want to leave and your videos are a massive part of that as take things to another level in detail .Still have nt made my main purchase but have bought 3 other watches in the meantime and the knowledge I 'm gaining is great and a lot of fun too .When you have guys like you ,just one more watch ,urban gentry and timeteller the love and enthusiasm comes thru to the viewer and now I'm in love with watches too .Priceless.

[@itsallrobbish]

True2022 brilliant, you’ve picked the best reviewers, right there!

[@Felippeber]

Somehow your language is very formal and at the same time you drop the exact words to give the right explanation 👍

[@generaldestruction3084]

Thumbs up man awesome videos you put out I find myself getting lost in watching so many of them. The watch and learn series is awesome I’ve learned a ton from watching them. I wear a Seamaster 300m I wanted the Speedmaster but I wear mine day in and out running heavy equipment and the Speedmaster just had more than I need. Keep up the good work!

[@islandwatch]

Thanks!

[@lehtosneva9512]

Another great video. I really enjoy watching these. Keep up the good work!

[@islandwatch]

Thanks!

[@pierrezapata90]

This video is phenomenal. Thank you so much for making a video like this. It is so informative and I love show you show your own test in real time

[@islandwatch]

Thanks for watching!

[@dennisalonso1029]

Great video. Just enough technical info to explain things without getting into the weeds.

[@islandwatch]

Thanks; I try to keep it light.

[@Resolute900]

Just discovered your channel and now a new subscriber. Thank you very much for sharing your knowledge, passion and expertise on the subject.

[@Tom_H327]

Marc truly is a smart man. I've learned a lot. The amazing thing is ; as a watch enthusiast, I didn't know I needed to know these things until Marc told me about them. 😂😉🤣

[@pjrive6668]

I have an SEIKO SKX007 and it's makes -7 seconds per Day with heavy use, i go dancing and Mountainbiking 4 times a week and i am REALLY really amazed with this watch. Greetings from Costa Rica.

[@itsallrobbish]

Pj Rive a legendary timepiece

[@EvilUnderTone]

I have adjusted Seiko Presage 6L35 to within a couple of seconds per day. Very under rated brand still. I'd like to see a $500 Rolex that can keep up with a Seiko personally :)

[@nrs6956]

Thank you. Good explanation. Is it possible to adjust the quartz movement for accuracy?

[@gregalonzo747]

Another informative video. FYI, Certina has a quartz chronometer. I bought one for my father.

[@richardtwyning]

Just discovered your videos and loving them. I was looking around for information as I'm honoured that my wife just bought me an Omega Seamaster Chronograph for my 50th birthday. Although, I still love my Citizen Skyhawk and my Citizen Divers watch :-) P.S. as of 2020, Omega don't supply the certificate, but on their web site you can obtain the test information, which I must get round to doing.

[@frankiecraft6674]

I just ordered the seiko solar SNE125 from you. Love the videos. Very informative.

[@islandwatch]

I appreciate the business, thank you.

[@abderrahmanelarchi]

Great video Marc as usual

[@islandwatch]

Thank you.

[@gtgene]

Thanks for this video, Marc. Do automatic movements drift so many seconds in one direction like a quartz watch, or drift plus or minus depending on position?

[@nrs6956]

Highly informative review. Many thanks.

[@edwardblack7133]

Hi MArc...can you use that equipment to check a spring drive accuracy? I was thinking the machine uses a microphone checking the escapement so it wouldnt work with the spring drive?

[@timemachineeddie1146]

An amazing video. Thanks for sharing.

[@johnatkinson5693]

Thanks for a very informative video. My Vostoks run at about a minute fast or slow a week ,but I still love them and adjust them accordingly as we all do who have Mechanical watches?

[@giannmilanista]

Excellent job as always, Mark! -GCR

[@islandwatch]

Thank you sir!

[@hendimam525]

Hey Marc, first of all thank you for your expertise! I learned a lot from your vids. Nice that you mention at the end that it has'nt got to be a chronometer certified watch in terms of accuracy! I own a Sinn Aquis date with the Sellita SW 200-1. At the moment it runs +/- 1 sec per day! It's all about regulation ;-) Greetings from Germany

[@islandwatch]

That's awesome, enjoy!

[@fabriziodutto7508]

Wow! The seiko monster orange! I badly need one :-( Thank you so much for your videos, all very informative!!

[@thelifeofjools8384]

Great series ... Really informative ! Many thanks...J

[@islandwatch]

Thank you.

[@donp2166]

Does the accuracy standard tend to successfully make the jump from the movement testing out in controlled lab conditions, to a finished, encased watch with face and hands, on a live, active end user?

[@artswri]

Great stuff thanks!

[@Tomatohater64]

Superb explanation on the scope of chronometers.

[@islandwatch]

Thanks!

[@hocklaikhor8353]

i had been wrong all this while. i thought chronometer = chronograph. Tks Marc! Now i know better.

[@islandwatch]

Glad its cleared up now!

[@melchizedekpsj]

Thanks for the video! Very informative!

[@islandwatch]

Glad you enjoyed.

[@melchizedekpsj]

Long Island Watch Definitely. Much appreciated!

[@bernardocourrege6283]

Excellent Marc!

[@islandwatch]

Thanks!

[@mayankkaloni]

Great video. Although it's a shame that chronometer settings don't hold over time. It is understandable since we are dealing with mechanical watches. But then it raises the question that do we need to spend extra for these chronometers to begin with as they will eventually lose the accuracy. And as mentioned even a regular watch can be serviced to chronometer standard.

[@georgiivanov61]

What do you mean? You are spending extra for the supreme engineering, time spent and attention to detail. If you want value for money, just get a $10 digital Casio with chronograph, timer, perpetual calendar, calculator and a light that's almost bright enough to be used as a flashlight in the dark lol.

[@matthewhoover6154]

I have a chrono certificate from COSC but they didn't write any numbers on it. It came with the Tissot that says "Chronometer" on it, so I assume they certified it, but idk why the certificate would be blank.

[@SaturnNyne]

I'm starting to think of your titles as click-wait, instead of click-bait: unlike everyone else on youtube, you consistently under-sell and over-deliver. I kept seeing this and thinking, "I don't need to spend 23 minutes watching a video about how accurate chronometers are," but, as usual, your detailed description of the history and testing was fascinating beyond what the title promised.

[@AlexCastignani]

great video very informative!!!

[@islandwatch]

Appreciate you watching.

[@mikewysko2268]

Vert interesting. Thanks Mark.

[@Patrick_B687-3]

I've never been lucky enough to have a Rolex, or any other that ran +\- 2 new or otherwise. Great video Marc, so thanks for making it. I appreciate it, and realize it's an old standard, but I switch so often it really doesn't matter, but I don't get worried about it until something is pretty far out of range.

[@islandwatch]

Right!

[@jaimeandrescatano]

What is the brand and reference of the last watch with higher accuracy?

[@waterdawg08]

Why do i feel just a little smarter after watching this ? 😁 great video Marc..

[@islandwatch]

Great side effect!

[@Robert.Dickson]

Another great video, I will never stop adoring that yachtmaster.

[@islandwatch]

Thanks, me too.

[@Leptospirosi]

Great video!

[@islandwatch]

Thank you for watching.

[@JunkfoodZombieGuns]

Is that Sinn at the end of the video a mechanical or a quartz? Can you even use that timegrapher on a quartz? Thanks.

[@rageshgr]

It's mechanical. Valjoux 7750

[@yusufshittusarumi3623]

Please how to reset 24h on edifice Casio watch ef 554

[@jasonwb6884]

Marc, a question you might able to answer. Are all chronometer movements top movements. Top movements being decorated and better parts like shock protection (incabloc) and better hair spring (nivarox). And what do you think about omegas meta certified process.

[@jfdomega7938]

Excellent. As are most of your videos!

[@islandwatch]

Thank you!

[@gregalonzo747]

I picked up a Certina Quartz Chronometer while on business in Europe. This is a fantastic time piece. I prefer quartz when I am working. Can you recommend a German quartz Chronometer? If any.

[@neilpiper9889]

I have a vintage chrometer. It's a Vostok Volna 2809 Precision from the 1950s. It's a homage to the 1948 Zenith 135. How the Soviets got the design is shrouded in mystery. No paperwork but it still keeps within 5 seconds per day. I have a Seagull m171s which has the Triovis Precision adjustment system in the movement. This is the more robust system than the Etachron used by the Swiss. My Seagull keeps within 2 to 3 seconds per day. You could do a video on the Triovis and Etachron systems and their relative merits.

[@drewsmith6066]

interesting thanks never knew this me ..great info

[@islandwatch]

Thanks for watching.

[@OscarRPalma]

What about the omega METAS master chronometer? In which category will fall?

[@nigellacey559]

Fascinating

[@wthaurthy2012]

don't mind my question, but when it is +12 sec does it mean the watch is running faster than it should have?

[@KRW628]

very informative

[@islandwatch]

Glad you enjoyed.

[@Red.Hot.Chili.Beans63]

My new Islander ISL-03 (wearing about 2 wks now) is loosing 5 seconds a day. Should I be happy with that?

[@nevahenuf]

Any plan to do a video on atomic syncing or even GPS watches? That's kind of the other technical extreme of accurate timekeeping.

[@islandwatch]

I guess it's possible, though is it interesting? Not many people would get the circuitry (me included!)

[@Billthesheepdog]

Marc? What was the third watch you put on the time grapher? Seems a very interesting company if they build such capable watches.

[@islandwatch]

Sinn

[@Billthesheepdog]

wow. I would not have guessed that.

[@99SuperKiller99]

The watch isn't actually running

[@jesperhoyheim8107]

Hi Marc! Will Your website receive and sell the new seiko presages in the nearest furure?

[@islandwatch]

Which ones? The Seiko USA ones? We should have soon.

[@72jenki]

Just one question. How many units of a certain movement need to be tested to get the certification? Is it just an initial few or an ongoing process? Let's say for example company A makes movement XYZ which they use in four different watch models. Do they only have to test a set number of units in the initial stages, or a set percentage of units from each model, set number of units a year etc etc?

[@islandwatch]

It is not a sample basis; if you have a COSC Chronometer, you can be sure that actual movement was tested. It is a 100% tested sample lot.

[@SuperWahidul]

mark please review a seiko Irish coffee limited edition watch,tq

[@greghemlock6679]

My steinhart in the 5th position gains 6 sec day crown up is 3 sec a day wound once a day out of rotation. Worn it deviates between 3 to 6 per day occasionally plus 7. Regularly wearing it seems to hold better a accuracy. Now pretty regularly resting it between wearing the seconds seem to be reproduced very well. So even though not cosc standards I would say its reasonably accurate but highly precise since reproduced times are constant if I have that correct. Cosc as I see it is a repeatable standard for certification. I'm familiar with this methodology because we use standards like this in analytical chemistry on geologic samples showing how much of an element like mercury will come out of an environmental sample treated for stabilization prior to landfill. Per EPA standards TCLP We agitate a 20 gram sample for 16 hours in a water solution spiked with inorganic acids to 5.7 pH then the resultant tested solvent has to be below 5ppb Hg mercury or other levels for other substances before it can be land filled. This TCLP test toxic caracteristic leaching procedure is supposed to emulate rainfall for 16 hours through the landfill. 5.7 is the natural pH of rain water. Yes Virginia ALL rainfall is acidic due to carbonic acid in the atmosphere.

[@ammarch1319]

great video mark as usual, i wish my static mechanics professor back in the day was as good as you, LOL

[@islandwatch]

LOL; I had the same guy for 2 straight years. Statics, dynamics, vibe, . . .

[@ammarch1319]

Ii am an architect so no dynamics but still you seem to be lucky. professor wise lol

[@AlTheEngineer]

Hey Mark! Thanks for the video, I have a certified chronometer (an Omega Sea Master Ploprof 1200) from 2012 and right now it is always doing -2 seconds a day no matter what position I put it in, it never does any positive time, it always does minus 2 seconds. I tried to set it on the table in all different positions over night and it's always the same outcome. Does that mean it needs to be serviced? It has a caliber 8500.

[@islandwatch]

It's operating well within spec; but you can just regulate it up a bit.

[@AlTheEngineer]

It's just interesting to me that it's always -2 regardless of position. But you are right it is well within spec, I might ask my local watch maker to regulate it for me when I pass by there. Thanks for the video as always, extremely informative!

[@tayyabpirzada146]

-2 is insanely good timekeeping

[@AlTheEngineer]

Yes, it is! I am just concerned that it is always -2 regardless of the position, it never goes positive (to cancel out the error for example), and I think with a bit of regulation I can get it to even do better!

[@lenpowell6647]

There is a thing ref engineers rule that will make sense? Cheers .

[@williamhudson5197]

Mark, what was the name of the last watch with perfect timing. I couldn't quite make you out on the name...

[@jos5979]

If recent purchased rolex gives -3, -4sec per day With no gaining. Do you think it should be serviced? It is one month old.

[@lenpowell6647]

Superb.

[@marknocbogataj9753]

Are you sure you can bring a Seiko movement to COSC? I think they only do the Swiss-made mechanisms.

[@robertbeucler4804]

Thx Marc! Do you anticipate carrying any chronometers in the future?

[@islandwatch]

I have in the past, so I wouldn't rule it out.

[@ashleyb66]

So, if someone in 2017 is selling say a vintage watch with an ETA movement that was once COSC certified, does that mean the seller could ask for a bigger price? In other words, am I correct in thinking that what distinguishes a COSC movement is the adjustment/regulation process it goes through and not the movement per se?

[@islandwatch]

It's the testing it undergoes; but if its vintage, it's probably out of COSC specs by now.

[@ashleyb66]

Long Island Watch. Understand. So the stamping on the dial of a Rolex "superlative chronometer" is a time sensitive state. In other words Rolex assumes you will get it back to COSC once it falls out of accuracy. I can't believe that every Rolex owner with a "superlative chronometer" stamped on the dial would be sending their watch back to the Swiss for re-Coscing...😵😵😵😵

[@nunomc2815]

This is a Swiss Standard, right Marc ? Is there any equivalent standard for japanese fine wristwatch industry ? I know all mechanical GS exceed COSC requirements, but can they, as a japanese brand, require a COSC certification ?

[@zeroman614]

ISO standards are international accepted quality standards. ISO regulates quality standards for nearly every area of industry/production.

[@islandwatch]

The Swiss one is the most recognized. If you go to Wikipedia, they talk about others. But, technically, only those certified by COSC can carry the Chronometer mark.

[@arupian666]

After the Swiss got all pissy with Seiko for using the Chronometer label on their watches and sent Seiko a strongly worded cease and desist letter, I believe that a Japanese association was formed for independant testing to chronometer standards. I think it went kaput at some point though. You're right. Grand Seiko 9F series movements must achieve -3/+5 seconds/day in order to pass inspection. In 6 positions. As unnatural (as Marc said) it may be, Seiko believe that it should still be part of the testing procedure. My Grand Seiko runs about 2 seconds fast/day. Actually, my SARB035 runs to better than COSC standards.

[@richardprice7763]

My Christopher Ward Trident COSC chronometer (ETA 2836) started losing 8 seconds per day after I took it swimming for the first time. Very odd as it's less than six months old. It's back at CW at the moment under their 5 year movement warranty....

[@sanjursan]

Dang, I love that Sinn!

[@islandwatch]

Me too; it's a brick.

[@Billthesheepdog]

Yeah. cant beat 'shack' for time hack! 00, wow.

[@user-et8vm9cc3t]

I just love how it keeps showing 0 sec/day AND no beat error whatsoever !!! Amazing !

[@99SuperKiller99]

It isn't running at all, that's why it hits 0 across the board

[@99SuperKiller99]

@@user-et8vm9cc3t that's actually because it isn't running at all. Watch the hands, no movement

[@spookyspoots]

I was never a Rolex fan, but found myself feeling a growing attraction to them throughout this video... then the Sinn came along and that attraction just all came justifiably crashing down. Very climactic.

[@islandwatch]

Thank you for watching it.

[@CLaw-tb5gg]

I'd like to give some love to the humble ETA 2824-2. Maybe I've just had good luck, but every one I've owned (in Steinharts mostly) has been really accurate. Just measured my Ocean Black, which came in at +0.6s/d.

[@totisanchez3607]

Two thumbs up !

[@CLaw-tb5gg]

Also I've been perving over the Sinn 757 S UTC for ages now - think you might have just tipped me over.

[@islandwatch]

Ha! Great piece.

[@stationplaza4631]

The Yachtmaster is the star of this show...Love it !

[@TheWayofGrace89]

Rolex continues to surprise me.. I always wondered why they cost so, so much more than other similar pieces. It's becoming a clearer picture.. awesome

[@islandwatch]

Fantastic pieces.

[@royaguirre551]

Great video very informative. I had a bad experience with a Rolex watch and I wanted to see what is wrong with those watches. I got a new Rolex date just 2019, it gains time every day. 13.5 seconds every 72 hours. In 3 months of wearing it without adjusting the time it gain 7 minutes. Worth it? I don't thinks so. I don't wear it anymore. I just cant trust an overvalue brand that cant keep time right.

[@romariomargera4245]

Do you guys know if its safe to ship to Mexico? or should i order a watch to the US? thanks.

[@Pollogallinoo]

voy a dejar este comentario por si alguien contesta y de casualidad sabes cuanto cobran de impuestos?

[@islandwatch]

USA is less of an issue; but we do ship to MX.

[@romariomargera4245]

Thank you a lot. :)

[@masonsimon9172]

This man is a mix of Mr. Bean and Charlie Sheen

[@SaturnNyne]

With a bit of Victor Mature too.

[@Billthesheepdog]

Marc, My Omega and Tudor Pelagos will track at 1 to 3 seconds minus daily if left tosit face up and not worn. If I wear either for all day or all night they will not be that great on hack. I assume it is normal to see COSC timepieces wander like this when worn all night? I sleep with a watch on sometimes. Sometimes a Gshock sometimes my new pretties. This is OK I assume?

[@islandwatch]

They should keep great time in all positions and all combinations thereof.

[@Billthesheepdog]

well they are both new... should I talk to the dealers for a look see? strange that both would do it. Both are less than 2 months old.

[@vladimirsnigur253]

What bout Certina? I heard they adjust their movements to chronometer accuracy but do not certify all of them.

[@igorcicala7]

My Longines automatic watch runs + 1-2 sec/ day without any kind of certifications :)

[@robinj.9329]

I've been using Sakio quartz watches for years. And I hack once a week to the WWV or WWVH signals. Never out my more then 3 or 4 seconds!

[@EddyWoon]

Great presentation and explanation! I may have to invest in a chronometer when I am adding more mechanical pieces to my collection.

[@islandwatch]

Thank you!

[@Bhatakti_Hawas]

So what is the Geneve Seal ??

[@islandwatch]

A higher echelon of watchmaking; it's not just accuracy.

[@KillerByte666]

Thanks Mark ! Very interesting video. But where is the wrist Check ??!!! :)

[@islandwatch]

Sometimes I just forget!

[@KillerByte666]

No problem :) You know each time you post a new video, I'm wandering which damn' watch(es) Mark will show us this time. Yeah, I'm insane :) Thank you for the time spent learning us some watch basis and more (in a comprehensible way) !

[@daleschmidt7157]

Plus or minus x seconds per a given time period are not always additive; they can be subtractive. So a COSC mechanical movement could hold time to within a few seconds per month or per quarter or.....etc.

[@islandwatch]

Yes!

[@nickg2954]

Great Vid!!Do u wanna sell that Breitling?

[@islandwatch]

I bought it used years ago; I love it. NOPE!

[@nickg2954]

Long Island Watch lol..I hear ya!I wouldn't either.. Beautiful Piece!!

[@defensemen16]

Marc you guys need to cut a deal with Sinn! Watchbuys prices are outrageous

[@islandwatch]

Contact Sinn on my behalf. I tried to talk to them at Basel but they only want to deal with WB.

[@carmadme]

The 6r15d in my seiko runs perfect during the day at work it looses time to about 3-4 seconds at rest after work it gains what it lost going to about + 2-3/d

[@jazz1ba]

My Certina DS Action Powermatic80 is running -3 secs a day.

[@gearrunner]

I just checked my Lum Tec 600M I've owned it 15 days and it's gained +15 secs. So 1 second a day. That's pretty good for a $800 watch.

[@islandwatch]

That's great for a $2000 watch!

[@vectraB97]

My cheap guanqin gj16034 with miyota 8205 runs 4seconds slow every 24hour. I've only owned It 4days. I paid like 53$ on Ebay, free shipping.

[@istvantoth7431]

Yep, Longines Hydroconquest Quartz movements are black-belt ... 7 jewel high quality ETA movements ...

[@thermionic1234567]

What’s a Perlative Cerenometer?

[@user-et8vm9cc3t]

That's a mark of true quality that every Rolleck's Cosmogroove DayTune and every Rollckex Sambariner has to have !

[@jhstylewon1172]

My Tissot Seastar 1000 is running at -2/day. I'm so lucky.