Automatic Watch Accuracy Checklist: 12 Things to Check

Before You Call the Service Center: 12 Things to Check on a Watch Running Off

Automatic watch accuracy shifts with winding, wear time, position, and temperature, so judge it over several days of logs, not one reading.

If your automatic watch is suddenly faster or slower than yesterday, check how you have been using it before you hand it to a service center. A mechanical watch's rate changes daily with how fully it is wound, how many hours it was worn, and how it rested overnight, so one comparison cannot tell you whether something is actually broken.

This list groups twelve checks you can do without opening the case, in the order of winding, wear, position, environment, and records. The numbers reflect ease of checking, not importance: the early items you can do today, and the later ones are what you judge with after a few days of notes.

How to read it

If the deviation built up slowly, start with the habits in items 1 to 6.
If it changed suddenly one day, look first at shock, magnetism, and timing in items 7 to 10.
Either way, use items 11 and 12 to compare against the official spec and organize your log before contacting service.

Log Daily Deviation Under Consistent Conditions

If the reference time, the hour you compare, and your wear pattern change every day, you cannot tell which way the watch is drifting. Compare against the same reference clock at a similar time daily, and jot down wear hours and the overnight position next to each number. A phone clock that syncs automatically works well as a reference. For the first few days, only record; do not judge yet.

Don't Conclude Anything From a Single Reading

A mechanical watch can run differently from one day to the next, so a single number says very little about whether something is wrong. Do not treat +8 seconds yesterday and -3 today as a fault. Look at the trend and average across at least three to five days. A steady lean in one direction is a meaningful signal, while scattered readings usually reflect differences in wear conditions.

Confirm It's Fully Wound

When mainspring power runs low, amplitude drops and the watch may run slow or seem to stall. If you have not worn it for a few days, wind it fully by the crown before setting the time. Winding method and recommended turns vary by model, so follow the manual, and if it stops taking more turns, do not force the crown. Log the deviation again after winding to separate causes.

Track Wear Time and Activity Level

An automatic movement only fills its mainspring when wrist motion spins the rotor. A day spent sitting at a desk, or a shorter-than-usual wear, can leave less reserve and change how the watch behaves. Mark those days as low activity in your log. When you later see a big deviation, checking whether it overlaps with those days helps separate a watch issue from a lifestyle one.

Check the Overnight Resting Position

Whether the watch rests dial up or on its crown side changes the direction of gravity acting on the balance, and the rate shifts with it. Positional differences are a normal trait, so resting it the same way each night is the basis for comparison. If you deliberately try a different position, hold it for several days to get a meaningful reading, and always note that you changed it.

Watch for Temperature Swings

The metal parts and mainspring inside a watch can respond slightly to temperature. Think back to whether it spent a long time in a hot car in summer, near a sauna, or outdoors in deep winter. If the deviation jumped only after such a day, the environment may be the cause. Avoid extremes on purpose; just keep it indoors for a few days and see whether the rate settles back.

Check for Possible Magnetic Exposure

Leaving a watch near speakers, magnetic clasp cases, magnetic bag buckles, or some electronics for a long time can magnetize it and make the deviation jump. A sudden, much faster rate is the typical sign. Think about whether any exposure happened and note the date, but do not try to demagnetize it yourself. Without proper equipment it can do more harm, so having a service center check it is the safer route.

Check for Recent Shock

After a drop, or after sports that put repeated hard shocks through the wrist, such as golf or tennis, parts you cannot see may be affected. Even if the case looks fine, a change in the balance assembly can alter the rate or stop the watch. Recall whether anything like that happened recently, and if so, record the date and circumstances so you can pass them to service as they are.

Watch the Date-Change Window

A date window that flips well after midnight, or changes slowly, can look like a fault, yet on some models it is normal behavior. Check the date-change method in the manual first, and make sure the AM/PM setting was not flipped when you last set the time. Avoid quickly turning the date by the crown during the hours when the change mechanism is most vulnerable.

Distinguish Sudden Change From Gradual Drift

A slowly accumulated deviation and one that jumps on a particular day likely have different causes. The first tends to tie to usage habits or lubrication changes, the second more often to an event such as a shock or magnetism. If you pin down the date the change began, it is easier to retrace what happened around it. Service technicians also use that information as a starting point for diagnosis.

Compare Against the Official Spec, Not a Guess

The accuracy a manufacturer states is a value tied to set test conditions and a specific caliber, so plugging in a number measured in daily life can mislead. Check your watch's caliber and official specification first, then compare on the same basis. Even as of October 2026, tolerance differs by model, so confirm the exact figure through the manufacturer's official channel or warranty booklet.

Bring a Full Log When You Request Service

Telling a service center only that it runs fast or slow makes the inspection slower. Bring daily deviation, wear time, overnight position, any shock or magnetic exposure, and the date the rate changed. A photo of a few days of log on your phone is enough. Also confirm the repair scope, cost, and warranty coverage directly with the official channel when you drop it off.

How to work through it

If the deviation grew gradually, go through items 1 to 6 in order and build up a few days of notes. Fixing just item 3 (winding) and item 5 (resting position) often steadies the numbers. If it jumped suddenly, think first of item 7 (magnetism) and item 8 (shock), and pin down the date the change began, as in item 10.

If large deviations or stoppages keep recurring even after a full wind, organizing your log as in item 12 and contacting official service is the fastest path. Do not try demagnetizing or adjusting the movement yourself. This is general guidance and standards differ by model, so please confirm with the manufacturer's official channel.

Frequently asked questions

How many seconds a day is normal for a mechanical watch?

The acceptable range depends on the caliber and its official test standard, so compare against your model's actual spec under the same conditions. That is more accurate than a vague rule of thumb.

What should I do if the watch was near a magnet?

Think back on whether it sat near a speaker, magnetic clasp, or other strong magnetic source for a long time, but do not attempt demagnetizing it yourself. Note the exposure and any deviation that followed, and pass that to service.

Should a sudden accuracy change go straight to a service center?

First work out whether it is a gradual drift or a sudden jump. If a large deviation or stoppage keeps recurring even after a full wind, compile your log and contact official service.

How fully should I wind the watch before checking accuracy?

Recommended winding method and turns vary by model, so follow the manual. After a few days off the wrist, compare only once it is fully wound so you can separate low-power effects. Do not force the crown.

What position is best for resting the watch overnight?

There is no single right answer; resting it the same way each night is what makes comparison work. Rate differences by position are normal, so if you change it, hold the new position for days and record that.

What should I bring to the service center?

Bring a log of daily deviation, wear time, overnight position, any shock or magnetic exposure, and when the change started. A photo of your notes on a phone is enough, and confirm repair scope and cost through the official channel at drop-off.

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How to read it

Log Daily Deviation Under Consistent ConditionsUpvote

Don't Conclude Anything From a Single ReadingUpvote

Confirm It's Fully WoundUpvote

Track Wear Time and Activity LevelUpvote

Check the Overnight Resting PositionUpvote

Watch for Temperature SwingsUpvote

Check for Possible Magnetic ExposureUpvote

Check for Recent ShockUpvote

Watch the Date-Change WindowUpvote

Distinguish Sudden Change From Gradual DriftUpvote

Compare Against the Official Spec, Not a GuessUpvote

Bring a Full Log When You Request ServiceUpvote