Why Is My Automatic Watch Losing or Gaining Time?
An automatic watch losing or gaining a few seconds a day is normal and expected. A mechanical movement is not a quartz chip, and most run within roughly -10 to +20 seconds per day, some tighter. When the drift is small, the usual culprits are magnetism, a partly wound mainspring, or the position the watch rests in overnight. When it runs to whole minutes a day, that points to something needing attention, most often a service. Here is how to work out which you are dealing with.
First, what counts as normal
Mechanical watches keep time by the steady swing of a balance wheel, and countless tiny factors nudge that rate. A few seconds a day either way is not a fault; it is the nature of the mechanism. Before you worry, measure properly: set the watch against an accurate reference, wear it normally for several days, and note the total gain or loss. A watch that is 5 seconds fast per day is running well. One that is 3 minutes fast per day is not, and the difference in cause is what the rest of this covers. If you want the full picture on movements, our automatic vs quartz guide explains why mechanical accuracy works the way it does.
The common causes, from most to least likely
1. Magnetism
This is the most frequent reason a watch suddenly starts gaining time, often dramatically. The balance spring is fine steel, and if its coils get magnetised they cling together, shortening the effective spring and making the watch run fast, sometimes minutes a day. Modern life is full of magnets: laptop and phone speakers, tablet covers, magnetic clasps and bag closures, fridge doors. If your timekeeping went haywire overnight, magnetism is the first suspect. A watchmaker can demagnetise it in seconds, and the rate usually returns to normal.
2. Low power reserve
A mainspring delivers its most even torque when well wound. Let the charge run low, by wearing the watch too gently to keep the rotor moving, or leaving it off overnight, and the falling torque makes the rate drift, usually slow. If your watch loses time on quiet, desk-bound days but keeps better time when you are active, low power reserve is likely. Give it a full hand-wind of 30 to 40 turns in the morning; our winding guide covers the method.
3. Resting position overnight
A mechanical watch runs at slightly different rates in different positions, dial-up, crown-down, and so on, because gravity acts on the balance differently in each. How you leave it off the wrist for eight hours a night can tilt the daily average. If your watch gains a little, try resting it in a position that makes it run slow to cancel the difference, for instance crown-up or dial-down. Experiment over a few nights and you can often shave the drift down without any repair.
4. Temperature and activity
Extremes of heat and cold change the rate slightly, and an unusually active or sedentary day shifts how much the watch is wound. These are minor next to the three above, but they explain why the same watch varies a little day to day.
What each cause looks like
| Symptom | Likely cause | First fix |
|---|---|---|
| Suddenly fast, minutes a day | Magnetism | Demagnetise it |
| Slow on quiet days, better when active | Low power reserve | Hand-wind fully each morning |
| Small, consistent daily gain or loss | Resting position | Change overnight position |
| Growing drift, worse over months | Dried oils, wear | Book a service |
| Stops before its reserve is up | Friction inside the movement | Book a service |
When it is a service, not a setting
If the watch is drifting by whole minutes a day, the rate has got steadily worse over months, it stops well before its stated power reserve, or winding feels gritty, the movement likely needs servicing. Over years the lubricants dry out and friction rises, throwing off the rate. Demagnetising and repositioning will not fix a movement running dry. A full service cleans, re-oils and regulates it back to accuracy. Our automatic care guide covers keeping it healthy between services.
A sensible order to diagnose it
- Measure the true daily rate over several days against an accurate clock.
- Demagnetise if the watch suddenly ran fast; magnetism is the commonest quick fix.
- Wind it fully each morning and see whether a slow rate steadies.
- Adjust the overnight resting position to offset a small consistent gain or loss.
- Book a service if the drift is large, worsening, or paired with poor power reserve.
Serviced, tested automatics are in the automatic and mechanical collection and the wider shop. More routines sit in our watch guides.
Common questions
How many seconds a day is acceptable?
For most automatics, roughly -10 to +20 seconds per day is normal, and certified chronometers do better. A few seconds either way is not a fault. Whole minutes a day is, and needs looking at.
Why did my watch suddenly start running fast?
Almost always magnetism. The balance spring has become magnetised from a phone, laptop or magnetic clasp, making it run fast, sometimes by minutes. A watchmaker demagnetises it in seconds and the rate returns.
Can the position I store it in really change accuracy?
Yes. Gravity affects the balance differently in each position, so a watch runs at slightly different rates dial-up, crown-down, and so on. Resting it in a slow position overnight can offset a daytime gain.
When should I take it in for service?
When the drift runs to minutes a day, keeps worsening over months, the power reserve falls short, or winding feels gritty. Those point to dried oils and wear, which only a service resolves.