My Watch Gains or Loses Time: What Is Going On?

Your watch was running +2 seconds per day last month. Now it's gaining 20 seconds per day, or losing 30, or drifting erratically. Before you take it to a watchmaker, run through the five common causes. Most are easily identified and fixed at home or with basic equipment. This guide walks through the diagnostic in order.

The Five Causes, Ranked by Likelihood

Cause 1: Magnetism

Most common cause of sudden significant rate changes. Automatics exposed to magnetic fields develop magnetized hairsprings, which coil tighter and speed the balance wheel. The watch runs fast. Often dramatically fast — 20 to 60 seconds per day.

Common sources in daily life.

• Speaker magnets
• Laptop closure magnets
• Handbag clasps with magnets
• MagSafe phone accessories in direct contact
• Induction cooktops at close range
• Large electric motors and medical equipment

Diagnose. Hold a compass near the watch. If the needle deflects, the watch is magnetized. More sensitive: a timegrapher shows the characteristic pattern.

Fix. A $20 to $50 demagnetizer handles it in seconds. Most watchmakers offer the service for free. For full detail, see magnetism and watches.

Cause 2: Rest Position

Automatic watches run at slightly different rates depending on how they rest. Balance wheel friction varies by position. Watches resting flat on the back run differently than watches resting crown-down.

A watch that runs +2 seconds during the day (on your wrist) and ends up +8 seconds after a night in a specific drawer position is showing position variance. Not a defect. A characteristic.

Fix. Vary the overnight rest position. Test. If the drift pattern changes, rest position was the issue. COSC-certified chronometers are tested in multiple positions specifically because of this.

Cause 3: Wrong TPD on Winder

If your watch lives on a winder, wrong TPD settings produce gradual drift that looks like a rate issue but is actually a winding problem.

• TPD too high means the watch stays at max wind, where mainspring torque is at the upper end. Rate often runs slightly faster.
• TPD too low means the watch runs partially wound, where torque is inconsistent. Rate can drift in either direction.
• Wrong direction means half the winder cycles don't wind. Effective TPD is much lower than set.

Fix. Check your caliber against the TPD reference. Adjust the winder to match. For per-rotor direction setup, see watch winder direction.

Cause 4: Temperature

Mechanical watch rates vary with temperature. At 5C, a watch may run 3 to 5 seconds per day slower than at 20C. In a Dubai apartment at 28C, the same watch may run 2 to 3 seconds per day faster.

Short-term exposure (a cold car overnight, a hot day at the beach) produces temporary drift. Long-term climate differences produce sustained differences.

Fix. For temporary drift, let the watch stabilize at room temperature. For sustained differences, accept that your watch runs slightly differently in different climates. Modern silicon hairsprings are less temperature-sensitive than traditional steel.

Cause 5: Service Overdue

If you've ruled out magnetism, position, TPD, and temperature, the answer is usually service. Old lubricants thicken. Parts wear. A watch that's 8 years old and runs +15 seconds per day is telling you the service interval has passed.

Fix. Authorized service. Basic automatic service costs $300 to $700. Complicated pieces run $800 to $3,000+. See watch service intervals for what to expect.

How to Measure Your Watch's Rate

Three methods, from simple to precise.

Phone time comparison. Set your watch to atomic time. Check against the same atomic time 7 days later. Divide difference by 7 for seconds per day.

Timegrapher apps. Phone apps using the microphone to detect beat sounds. Less accurate than dedicated hardware but useful for rough diagnostics.

Dedicated timing machine. For serious collectors, a timegrapher like the Weishi 1000 ($180 to $300) provides precise rate, amplitude, and beat error readings. See watch timing machine guide.

Reasonable Accuracy Expectations

For context on what these numbers mean, see how to read watch accuracy numbers.

When to See a Watchmaker

Service is warranted when.

• Rate exceeds spec after demagnetization and settings check
• Rate is erratic across multiple days
• Watch is more than 5 to 7 years past last service
• Power reserve is noticeably shorter than new
• Other symptoms accompany the rate issue (scraping, moisture, crown feel)

Frequently Asked Questions

My watch runs +20 seconds per day. Is that normal?

For a non-certified automatic, yes, within spec. For a COSC chronometer, no, likely magnetism or service issue.

Can the winder cause my watch to run fast?

Indirectly. Wrong TPD or direction over time can lead to rate issues. A quality winder with correct settings won't cause drift.

Does a watch slow down near the end of power reserve?

Yes, slightly. Mainspring torque drops as the reserve runs out. This is normal and why winders matter for accuracy.

How often should I check my watch's rate?

Once or twice a year is plenty for most collectors. Every service visit is a natural check.

Should I adjust my watch myself?

No. Regulating a movement requires opening the case and precision tools. Leave it to watchmakers.

Does altitude affect watch accuracy?

Marginally. Significant only at extreme altitudes. Normal cities and flights don't measurably affect rate.

Is it worth buying a timegrapher?

For collectors with 10+ mechanical watches who care about accuracy, yes. For casual owners, no.

Run the Diagnostic

Work through causes 1-4 before booking service. Most rate issues resolve at the demagnetization or TPD stage. If the drift persists, book a watchmaker visit. For winder sizing to solve rotation-related rate issues, browse the Winder Series.

Related reading: why did my automatic stop, watch accuracy guide, magnetism and watches.