Watch Running Fast or Slow – Here are the Most Common Reasons

By Montredo in Watch 101
May 13, 2019
Watch Running Fast or Slow – Here are the Most Common Reasons


Is your watch gaining or losing time every day? Very often when a customer comes to us, the reason is an inaccurate running of their watch. First of all, a claim about a 10-minute delay or advance on the watch has to be put into perspective and interpreted correctly by the watchmaker. For example, the timegrapher detects a deviation of +8 seconds per day (this is considered good accuracy for a mechanical watch). Over two months this variation accumulates, and that watch will be 8 minutes fast (8 s/d x 60 d = 480 s = 8 minutes).

The general rule for mechanical watches is that a deviation of 10 seconds or less per day is good. That’s when my customers usually disagree: “But my neighbor tells me that his Rolex has been 100% accurate for five years with no time deviations ever”. Well, simply put: This is absolutely impossible! It is a scientifically proven fact that isochronism (consistent oscillation) cannot remain constant in a wearable watch. Of course, there are reasons to cause a watch to be unduly fast or slow.

A few of the reasons why a watch may be fast:

• The movement requires professional service.
• The balance spring has been magnetized (this may cause the watch to go fast by as much as several hours per day).
• The watch has sustained some significant impact and caused the last winding in the spring to skip forward.
• The spring is clinging together.
• An impact on the watch altered the spring’s key.

And some causes to make a watch slow:

• The movement needs to be professionally serviced.
• An impact caused the dial to move and create binding on the digits (this is becoming more frequent lately)
• An impact altered the spring’s key.

Anytime when your watch is running fast or slow, it is advisable to see a watchmaker and let them diagnose the cause for the inaccuracy. Most cases are resolved very simply by fine-tuning the watch on the timegrapher. Depending on the watch and your location the cost runs somewhere between EUR 20 and 50. Please don’t do the same as one of my customers: He attempted to regulate his IWC Da Vinci himself, and in doing so, he caused significant damage of 5,000 Euros.

Let me get back to the subject of magnetism very quickly before I conclude. The watch manufacturing community has collected data, which shows that 80% of watches that require service are magnetized (to greater or lesser extent). Why, you ask? Because we are surrounded by magnetic fields. Just think of all the smartphones, purses and briefcases with magnetic closures and digital devices everywhere. In response to the effects of our increasingly digital environment and its magnetism watch manufacturers have started to use silicon balance springs over the past few years. Many instances of watches running slowly or fast would not have happened in the first place, if the watch was anti-magnetic.


Ulrich Kriescher

Ulrich Kriescher is a German TV Personality and Master Watchmaker based in Würselen, Germany. His watch workshop is specialised on repairing luxury watches, especially from Rolex.

Previous comments (4)

  1. Hi. Very interesting. I have a 1930’s Selex that needed a service. Gave it to Clarke and sons of Lewis UK. Web site very convincing of being competant. Returned to me after 6 months but I had to return it. Damaged and running slow. Returned to me and still running 3 mins a day slow. Have paid £400 for service and new glass!!!! Do you recommend anyone in UK to look at it. Was my fathers so want it working as best as I can.

    June 27, 2020
  2. my Citizen Crystal Seven 33 jewel is running slow. i wear it 1-4 times a year for brief periods and events. it was purchased new by my father, i believe but not sure.
    is there a Citizen source to learn more about value and how to tune for correct timing?
    thank you from the U.S.

    December 19, 2020
  3. wow! This is a great article that explains just what I needed.

    I like the way the author explains the concepts and I want to congratulate him on doing a great job.

    March 6, 2021
  4. Mike it’s a 1930s Selex watch, the movement is probably running as accurate as it’s going to get. Ive heard seasoned watchmakers who have worked with watches for decades on several occasionstell me 3 to 5 minuets per day is acceptable. Of course you there are a lot of variables which come into play. The overall quality of the movement, a precision made zenith movement is going to be more accurate than a crusty old Baumgartner.

    April 29, 2021