Hamilton · Hamilton H-31

Hamilton Intra-Matic Auto Chrono and Jazzmaster Performer power reserve: inside the H-31

The Hamilton Intra-Matic Auto Chrono, Jazzmaster Performer Auto Chrono and Chrono-Matic 50 all run on the H-31. Fully wound, it lasts about 60 hours, or two and a half days.

Updated September 2026 · Based on manufacturer specs, published reviews and watchmaker/owner reports

Watches that use the H-31

The H-31 powers Hamilton's retro-styled chronographs. Where the Khaki Aviation and Khaki Field chronographs use the 7750-based H-21, the H-31 is built on the Valjoux 7753, the version with a balanced 3-6-9 layout. That suits the 1960s and 1970s racing look Hamilton goes for in the Intra-Matic and Chrono-Matic.

Hamilton's other chronographs use different movements. The X-Wind, Converter and Khaki Field Auto Chrono use the H-21, and the hand-wound Intra-Matic Chronograph H uses the H-51.

Specs at a glance

History and where it came from

Hamilton has real history in automatic chronographs. In 1969 it was one of the partners, with Heuer, Büren and Breitling, behind the Chrono-Matic, or Calibre 11, one of the first automatic chronograph movements. Monochrome describes it as a modular design, with a chronograph plate fixed on a micro-rotor movement. The modern Chrono-Matic 50 and Intra-Matic chronographs borrow the look of that era.

The movement inside is newer. The Valjoux 7753 is a variant of the 7750, the automatic chronograph Edmond Capt designed in the early 1970s. It has the same cam-and-lever mechanism, but its subdials sit at 3, 6 and 9 instead of 12, 6 and 9. Like the H-21, Hamilton's version was reworked for a 60-hour reserve, well up on the standard movement. Monochrome reports that Hamilton improved the gear train and barrel and removed the regulator, "facilitating optimal reliability and precision".

The H-31 first appeared widely in the 2017 Intra-Matic 68, a 42 mm limited edition of 1,968 pieces based on Hamilton's 1968 Chronograph B. The permanent Intra-Matic Auto Chrono followed at 40 mm in 2019, the Chrono-Matic 50 the same year, and the Jazzmaster Performer Auto Chrono in 2023. Recent models, such as the 2025 all-black Intra-Matic and the black Jazzmaster Performer, specify a Nivachron balance spring.

Accuracy in the real world

Hamilton doesn't publish an accuracy figure for the H-31, and we didn't find enough timed owner reports to give a typical daily rate. Here's what the design tells you.

The 4 Hz beat gives it a steadier rate than a slower balance when the watch is knocked or changes position. The Nivachron spring in current models resists magnetism and temperature changes, which covers the most common reason a mechanical chronograph suddenly starts gaining. And the 60-hour mainspring means a watch you wear daily spends more of its time in the well-wound part of its reserve, where rates are usually most consistent.

The regulator change cuts both ways. Without a regulator arm, the rate can't be nudged with a quick tweak. It's adjusted at the balance instead, which takes more skill, the same trade-off owners of the Powermatic 80 run into. If your Intra-Matic Auto Chrono runs fast or slow, brand service is the safest place to have it regulated.

Reliability and servicing

The 7750 and 7753 family has been built for about fifty years and has a reputation as a tough, forgiving chronograph. There's no known systemic problem with the H-31.

• Brand service. Hamilton and Swatch Group service centers handle the H-31 and may exchange the movement rather than overhaul it, as with Hamilton's other H-series calibers.
• Independents. Many watchmakers know the 7753 well, but the H-31's long-reserve parts, regulator-free balance and Nivachron spring are specific to Hamilton. Ask about parts before you book.
• Thick cases. Not a reliability issue, but the 7753 stack makes every H-31 watch at least 14.45 mm thick.

Quirks worth knowing

• No hour counter on the Intra-Matic. The Intra-Matic Auto Chrono shows only a 30-minute counter and small seconds, so it's built for timing short intervals. The Jazzmaster Performer has a full three-register dial.
• The rotor noise. Like every 7750-family movement, the H-31 winds in one direction and the rotor spins freely and audibly the other way. It's normal.
• A closed back on some models. Monochrome notes the Intra-Matic's H-31 sits behind a solid steel caseback, so you won't see the "H" rotor on that model.
• Date setting. Avoid changing the date late at night, roughly 8pm to 2am, when the 7750 family's calendar is engaged. Here's why.
• Stop before reset. Always stop the chronograph before pressing reset.

How it compares

• Hamilton H-21: the 7750-based sibling with the same 60 hours and 4 Hz, usually with a day-date. It's in the X-Wind and Khaki Field Auto Chrono.
• Valjoux 7750: the base family, with about 42 hours. The H-31's extra reserve carries it through most weekends.
• ETA A05.H31: Tissot's 60-hour chronograph from the same 7750 family, in the PRX Automatic Chronograph. A close cousin inside Swatch Group.
• Zenith El Primero 400: a high-beat, column-wheel chronograph with about 50 hours, at a much higher price.
• TAG Heuer Heuer 02: an in-house column-wheel chronograph with 80 hours, if the reserve matters most to you.

Living with the 60-hour reserve

Sixty hours is two and a half days. Take your Intra-Matic Auto Chrono off at 6pm on Friday and it'll run until around 6am on Monday, so on a normal weekend it's still going when you pick it up. After a quiet week at a desk it may start the weekend only partly wound, and then it can stop on Sunday.

A chronograph is also more work to restart than a three-hander. You have to wind it, set the time and step the date through. If you rotate a Jazzmaster Performer with a couple of other watches, that gets old quickly. Watch Winder counts down the 60 hours for each watch you own and reminds you before one stops, so you can give the Intra-Matic a wear or a few turns of the crown in time. To check a specific gap, use the "Will my watch stop?" calculator.

Verdict

The H-31 does for the Valjoux 7753 what the H-21 does for the 7750: it keeps the proven, rugged chronograph architecture and adds the 60-hour reserve that makes it easier to live with. In the Intra-Matic Auto Chrono it sits under one of the best-looking affordable Swiss chronographs, and Nivachron in current models deals with magnetism. The downsides are thick cases, a rotor you can hear, no published accuracy spec, and regulation that's best left to the brand. If you want Hamilton's retro chronograph style with a movement that will get through a weekend, it's an easy choice.

FAQ

How long does a Hamilton Intra-Matic Auto Chrono run off the wrist?

A fully wound Intra-Matic Auto Chrono runs for about 60 hours, or two and a half days, on the H-31. If it wasn't fully wound when you took it off, it will stop sooner.

What movement is in the Hamilton Intra-Matic Auto Chrono?

The H-31, an automatic chronograph based on the Valjoux 7753, with a 4 Hz beat and a 60-hour reserve. Current versions use a Nivachron balance spring.

Does the Hamilton Intra-Matic Auto Chrono have an hour counter?

No. It shows a 30-minute counter at 3 o'clock and small seconds at 9, with the date at 6.

What movement is in the Hamilton Jazzmaster Performer Auto Chrono?

The Jazzmaster Performer Auto Chrono uses the H-31, with a 3-6-9 subdial layout, a 60-hour reserve and a Nivachron balance spring.

How accurate is the Hamilton Intra-Matic Auto Chrono?

Hamilton doesn't publish an accuracy figure for the H-31. It's a 4 Hz movement with an anti-magnetic Nivachron spring in current versions, and regulation is best done through Hamilton service.

Is the Hamilton H-31 a Valjoux 7753?

It's based on one. Hamilton had the gear train and barrel reworked for a 60-hour reserve and the regulator removed, and gives it its own "H" rotor.

What's the difference between the Hamilton H-31 and H-21?

Both are 60-hour, 4 Hz automatic chronographs from the Valjoux 7750 family. The H-31 is based on the 7753 layout and used in the Intra-Matic, Jazzmaster Performer and Chrono-Matic 50, while the H-21 is in the Khaki Aviation and Khaki Field chronographs.

Sources

• Hamilton: American Classic Intra-Matic Auto Chrono H38416711
• Monochrome: Review, Hamilton Intra-Matic Automatic Chronograph
• Monochrome: Hands-on, light green Hamilton Intra-Matic Auto Chrono
• Monochrome: Introducing the Hamilton Jazzmaster Performer collection
• Monochrome: Introducing the Hamilton Chrono-Matic 50 Auto Chrono

Watches we've reviewed with the Hamilton H-31

• Hamilton American Classic Intra-Matic Auto review

Keeping it running

• On an average day an automatic gains roughly 4 hours of reserve per hour on the wrist, so about 15 hours of wear fills the Hamilton H-31. Desk days charge more slowly.
• Most automatics can also be wound by the crown. If yours has stopped, a few dozen turns gets it going before you put it on.
• Off the wrist it stops about 60 hours after it was last full. Stopped sooner?
• On a watch winder, start at about 800 turns per day, clockwise. Winder settings for every movement.
• If it does stop, don't set the date between 9pm and 3am. Check if it's safe.

All Hamilton movements

Never let it stop

Watch Winder counts down the reserve of every watch you own and reminds you before one stops. It already knows the Hamilton H-31: type your watch's name and the reserve fills itself in.

Manufacturer's published figure. Real reserve varies with the watch's age and service; check your manual.