Why Is My Watch Losing Time? Five Causes and Their Fixes
"My Watch Is Running Fast/Slow — Is It Broken?"
Probably not. Mechanical watches drift by design; the fix is usually one of five simple causes. Work through this list before assuming failure.
Step 1: Establish the Baseline
Set your watch exactly by a trusted source. Check again after 24 hours of normal wear. Note the deviation:
- Within ±15 sec/day: excellent — factory-grade performance
- ±15–40 sec/day: acceptable, regulation can improve it
- Beyond ±40 sec/day: something specific is wrong — continue below
Cause 1: Magnetization (the #1 culprit)
Laptop speakers, magnetic clasps, tablet cases, fridge doors. Magnetized movements run fast — often dramatically (+1 minute/day or worse).
Fix: an inexpensive demagnetizer tool cures it in seconds. Full instructions in our maintenance guide.
Cause 2: Positional Variance (normal physics)
Mechanicals rate differently by position — dial-up overnight versus crown-down in a drawer can differ by 10+ seconds. Track how YOU store it; consistent storage gives consistent readings. Enthusiasts exploit this: storing crown-up overnight if the watch runs slow compensates naturally.
Cause 3: Full Wind vs Low Wind
A nearly-empty mainspring delivers slightly different torque than a full one. A watch checked right before dying may read differently than one worn all day. Judge accuracy mid-reserve.
Cause 4: Temperature Extremes
Left on a windowsill, car dashboard, or radiator-adjacent shelf, oils thin and rates shift. Store at room temperature.
Cause 5: Genuine Service Need
If deviation grew gradually over months, dried or degraded oil is likely — time for a standard cleaning and regulation. See our guide to regulating an automatic for what the process involves.
Quick Diagnostic Table
| Symptom | Likely Cause | Fix |
|---|---|---|
| Suddenly very fast | Magnetized | Demagnetize |
| Different rate each morning | Storage position | Pick one position |
| Slow when lightly worn | Low reserve | Full wind, retest |
| Gradual drift over months | Service due | Clean and regulate |
Frequently Asked Questions
How accurate should my NH35 be?
Factory spec allows -20/+40 sec/day; most examples settle around ±10–15 in daily wear.
Can I regulate it myself?
Yes with a timegrapher and steady hands — our regulation walkthrough shows the process.
My watch stopped entirely overnight.
That is the power reserve expiring, not a fault — wind and set it; details in our occasional-wear guide.
Keep Yours Accurate
- Sub Diver Watches — regulated before shipping
- Timing basics: chronographs explained