What is a good amplitude for a watch?

A good amplitude is one that sits between two limits: a ceiling checked dial up when the watch is fully wound, and a floor checked in a hanging position a day later. Sellita prints them in its technical documents at 315 and 200 degrees. Anything between the two, measured that way, is inside the maker's specification, whether or not it looks like the 270 to 310 band that most answers to this question quote.

That gap is the source of the confusion. An owner winds a watch, puts it on a timing machine, sees 245 degrees dial up and reads online that anything under 270 needs a service. The maker's test asks a different question, at a different time, in a different position, and a watch reading 245 at that moment can still be in specification. The figures below are taken from the makers' documents, and the procedure after them turns a home reading into one you can compare against those limits.

Amplitude limits by movement: the chart

Every figure below is printed in a movement maker's document, or, for Rolex, quoted from Rolex service data by a working watchmaker. Where a maker publishes no amplitude limit, the row says so and gives the test it uses instead.

Two things stand out. The first is how consistent Sellita is. Across six calibers and documents dated from 2012 to 2025, from the plain three-hand SW200-1 to the slim SW300-1, the pair is 315 and 200, and it does not change with grade: the older documents list Standard, Spécial, Premium and Chronomètre columns and print one amplitude figure across all of them. The exceptions are explainable. The SW510 chronograph's ceiling is 5 degrees lower, and the small SW100 is allowed 190 degrees at 24 hours in its Elaboré grade.

The second is who prints nothing. Seiko's technical guide for the 4R35B and 4R36A, the movement our 4R36 page covers, gives a lift angle of 53 degrees and a full rate test, but no amplitude figure. Miyota's 9015 sheet does the same. ETA's current technical communication for the 2824-2, version 25 of October 2022, gives a typical lift angle of 50 degrees and a minimum power reserve of 38 hours, and no amplitude limit either. For those movements there is no maker amplitude number to pass or fail, and anyone quoting one is quoting a workshop convention.

Why 270 to 310 keeps coming up

Because it describes what owners actually see. A healthy Swiss automatic, wound fully and laid dial up on a timing machine, often reads somewhere near 270 to 310 degrees, and our glossary entry on amplitude gives that band for a healthy modern movement. The trouble starts when the band is turned into a pass mark and applied to any position, at any state of wind, on any caliber.

On the top end it is too generous for some movements. In a 2018 OmegaForums thread, an owner of a Day-Date with the Rolex Cal. 1555 had read that "acceptable amplitude is generally considered between 270 to 310". The watchmaker who answered, posting as Archer and quoting the Rolex specifications he holds for the caliber, replied that the maximum full wind amplitude "should be no more than 280", common across the 1500 series "because higher amplitudes will cause rebanking", and that the more modern 3000 and 3130 have their maximum at 300. On a 1555, the top of the popular band is 30 degrees above Rolex's ceiling.

On the bottom end it is too strict. The maker's floor is 200 degrees, and it applies in the worst position after a day of running. A watch that reads 250 dial up an hour after winding has not failed anything, and the same watch may be well inside Sellita's limits. What the band does do well is describe a watch in good health at full wind, which is why it survives: it is a fair picture of normal. It is just not the test.

How the makers measure it

Sellita's documents spell out the conditions under the table, and they are stricter than most home readings.

• "Full wind" means 1 to 3 hours after winding. Sellita's note reads: "The check has to be done at full winding, referred to as 0 h, after 1 to 3 hours running."
• The ceiling is checked dial up. Sellita's code is CH, horizontal, dial up, which is where a balance usually swings widest because it rests on the end of one pivot.
• The floor is checked 6 o'clock up after 24 hours. That is the position watchmakers also call crown left, and Sellita's document gives both names.
• Complications off. All checks are made "without the calendar in function and chrono not coupled". A running chronograph takes energy from the same barrel and lowers the reading.
• A margin for the instrument. Sellita warns that "the inherent tolerance of the measuring instruments and the influence of temperature variations and the atmospheric pressure must be taken into account".
• Limits are for a lot, not a piece. "95 % of the pieces delivered in a lot must be within the specified limits", so a new movement just outside a figure is not automatically defective.

Seiko and Miyota time their checks differently because they test rate rather than swing. Seiko's guide says to wait about 5 minutes after winding for a stable oscillation and to measure three positions within 30 minutes, then again dial up after 24 hours. Miyota's sheet says to measure within 10 to 60 minutes of a full wind. Neither asks for an amplitude figure at any point.

Checking your own watch against the limits

A home reading becomes comparable with the makers' figures with four extra steps, and the first is the one most often skipped.

1. Set the right lift angle. The amplitude number is calculated from it. Sellita's limits assume Sellita's own lift angle, 50 degrees for the SW200-1 and 51 for the SW100, and our lift angle chart gives the figure for 37 calibers. On a timing machine left at its 52 degree default, a 50 degree movement swinging at the 315 ceiling reads about 328.
2. Wind fully, then wait. Wind by the crown until the mainspring is full, let the watch run an hour or more, and take the dial up reading. That is your full-wind figure to set against the ceiling.
3. Leave it 24 hours. Do not wind or wear it. Then measure with 6 o'clock up, crown left. That is your figure to set against the 200 degree floor.
4. Write down all three. Lift angle, time since winding and position travel with every number. Without them, a reading cannot be compared with the maker's figure, with an earlier reading, or with anyone else's.

If you do not own a timing machine, the rate test that Seiko and Miyota use needs only a reference clock and a week. Our guide to testing accuracy at home covers the method, and the timegrapher reading explainer turns a full readout of rate, amplitude and beat error into a verdict.

What your reading means, and what to do

Low amplitude rarely announces itself as a number first. Seiko's guide states the symptom directly: "When an amplitude of the balance becomes weak, the watch shows time loss, in general." On the wrist the common signs are a watch that loses more as the day goes on, or one that stops overnight on its dresser. The same loss is what Seiko's 24 hour check catches: it compares the dial up rate at full wind with the rate a day later, the isochronism fault, and allows them to differ by no more than 30 seconds a day.

A service is the fix for amplitude under the floor: our answer on how often to service a mechanical watch covers the intervals, and what a service costs covers the bill. Regulation does not help. It moves the rate, as our answer on whether a watch can be regulated explains, and leaves amplitude where it was.

When these limits stop applying

• The movement is vintage, or made by someone else. Rolex's ceiling for the 1500 series is 35 degrees below Sellita's. Older and different escapements can carry quite different figures, so a modern Swiss pair is not a safe stand-in for a 1960s caliber.
• The watch has a co-axial escapement, or no balance at all. A timing machine needs a special mode for Omega's co-axial (Witschi's Watch Expert III calls it Spe1), and neither a quartz watch nor a Spring Drive has a swinging balance to measure.
• The lift angle is unknown. Where no maker figure exists, the absolute amplitude number is unreliable by however far the setting is off. Compare the watch only with itself, at a fixed setting.
• A complication is running. Sellita measures with the chronograph disengaged and the calendar out of action. A reading taken with the chronograph running sits lower by design, because the chronograph draws on the same barrel.

Within those limits, the makers' answer is simpler than the forum one: under the ceiling at full wind, over 200 degrees a day later, and a service when it is not.