Quick answer: the Hamilton Khaki Field Mechanical 38 (£545) is a slim, hand-wound field watch with an 80-hour power reserve and 50 m of water resistance. KOMPAS (£535) is a 39 mm automatic with a Miyota 9039 movement, 100 m of water resistance, sapphire with anti-reflective coating on both sides and a dial inspired by the RAF sector clock. Choose the Hamilton if you enjoy winding a watch and want the classic. Choose KOMPAS if you want a watch that winds itself as you wear it and can go swimming. KOMPAS is our own brand, so read this with that in mind.
The Khaki Field Mechanical is the benchmark of the field watch category, and it is a fair yardstick for ours. Both cost almost the same, both are around 38–39 mm, and both are built to be read at a glance. Under the surface they are quite different watches.
Every Hamilton figure below comes from Hamilton's own UK website. Prices were checked on 8 November 2026 and change, so check before you buy.
At a glance
| KOMPAS | Khaki Field Mechanical 38 | Khaki Field Auto 38 | |
|---|---|---|---|
| UK price | £535 | £545 | £640 (leather), £715 (bracelet) |
| Movement | Miyota 9039 | Hamilton H-50 | Hamilton H-10 |
| Winding | Automatic, with hand-winding and hacking | Hand-wound only | Automatic |
| Power reserve | approx. 42 h | 80 h | 80 h |
| Case diameter | 39 mm | 38 mm | 38 mm |
| Lug to lug | 46.5 mm | 47 mm | 47 mm |
| Thickness | 10.4 mm | 9.5 mm | 11 mm |
| Lug width | 20 mm, quick-release | 20 mm | 20 mm |
| Crystal | Sapphire, AR both sides | Sapphire | Sapphire |
| Water resistance | 100 m | 50 m | 100 m |
| Lume | Swiss Super-LumiNova | Luminescent numerals | Super-LumiNova |
| Strap supplied | Rubber and nylon, both in the box | Textile NATO-style | Leather or steel bracelet |
Hamilton prices and specs from hamiltonwatch.com (UK), references H69439931 (Mechanical 38) and H70455533 / H70455133 (Auto 38). Checked 8 November 2026.
The big difference: hand-wound or automatic
This is the question that decides it for most people.
The Khaki Field Mechanical is hand-wound. It has no rotor, so it only runs if you turn the crown. In return, Hamilton's H-50 calibre stores 80 hours of power, so a full wind every couple of days keeps it going. Hamilton also fits it with a Nivachron balance spring, which is designed to resist magnetism. Many people love the ritual of winding a watch in the morning. Others forget, and find it stopped on the bedside table.
KOMPAS is automatic. The Miyota 9039 winds itself as you move, so if you wear it every day you never need to touch the crown. You can still wind it by hand, and the seconds hand stops when you pull the crown out (hacking), so you can set it to the second. The trade-off is power reserve: about 42 hours, roughly half the Hamilton's. Take it off on Friday night and it may need a few turns of the crown on Monday. Our guide to the Miyota 9039 explains the movement in detail, and the best Miyota 9039 watches compares other watches that use it.
Neither is better. Ask yourself whether you would enjoy winding a watch, or would rather not think about it.
Size and fit
On paper the two are almost identical: 38 mm against 39 mm, and 47 mm against 46.5 mm lug to lug. On the wrist, the lug-to-lug figure matters more than the diameter, and here they are within half a millimetre. If one fits you, the other almost certainly will.
The real difference is height. The Hamilton is 9.5 mm thick, because a hand-wound movement has no rotor. KOMPAS is 10.4 mm, which is still slim for an automatic with a sapphire crystal and an exhibition caseback. Both slide under a shirt cuff.
If your wrist is on the small side, our guide to the best field watch for small wrists compares nine options by lug-to-lug, and is a 39 mm watch right for my wrist? shows how to measure.
Water resistance and everyday toughness
Hamilton rates the Khaki Field Mechanical 38 to 50 m. That covers rain, hand-washing and the odd splash, but it is not a watch to swim in. KOMPAS is rated to 100 m, so you can swim and snorkel with it (it is not a scuba diving watch).
If you want the Hamilton look with 100 m, you need the Khaki Field Auto 38, which costs more and is thicker. Or the Khaki Field Mechanical 36, which is also rated to 100 m but uses an acrylic crystal rather than sapphire.
The dial: military classic or sector clock
The Hamilton dial is the classic military layout: large Arabic numerals with an inner track. It is honest, legible and instantly recognisable as a field watch.
KOMPAS takes a different route. The dial is divided into 12 triangular segments, one for every five minutes, inspired by the colour-coded sector clocks in RAF Fighter Command operations rooms in 1940. Controllers used those clocks to tell at a glance how old a report was. On the wrist, the segments make it easy to read minutes without counting markers. Our guide to how to read a 5-minute dial explains the history.
This is a matter of taste. If you want the archetype, the Hamilton is it. If you want a field watch with its own face and a story you can tell in a sentence, that is why KOMPAS exists.
What about the Khaki Field Auto 38?
If you like the Hamilton but want an automatic, the Khaki Field Auto 38 uses the H-10 calibre, which also has an 80-hour power reserve. It is rated to 100 m, measures 38 mm with a 47 mm lug to lug, and is 11 mm thick. It costs £640 on leather and £715 on a steel bracelet. Retailer listings show a date window at 3 o'clock, so it is not a pure time-only dial.
Against KOMPAS, the Auto 38 gives you nearly twice the power reserve and the Hamilton name, for about £105 more on a strap. KOMPAS gives you a time-only dial, two straps in the box and a slightly thinner case.
Price, buying and what's in the box
The Hamilton is sold through Hamilton's own site and most major UK jewellers, so you can usually try one on in person. Retailer prices sometimes sit below the £545 RRP.
KOMPAS is sold from our online store, with free tracked shipping to more than 40 countries, 14-day returns, Klarna and a 2-year international warranty. Every watch arrives with a rubber strap and a nylon strap in its colour, both quick-release. North (black) and South (blue) are in stock at the time of writing; East (green) and West (red) are sold out, with a restock list. All the key facts are on KOMPAS at a glance. Buying in Turkey? Our Turkish guide, en iyi saha saati, lists local prices for both Hamilton and KOMPAS.
Hamilton Khaki Field alternatives under £600
If you are looking at the Khaki Field Mechanical and want to see what else the money buys, these are the field watches we would shortlist.
| Watch | Price | Movement | Case | Lug to lug | Water resistance |
|---|---|---|---|---|---|
| KOMPAS | £535 | Miyota 9039 automatic | 39 mm | 46.5 mm | 100 m |
| Clemence Munro | from £549 | Miyota 9039 automatic | 37.5 mm | 45 mm | 150 m |
| Baltic Hermétique Tourer | from €550 (about £460)* | Miyota 9039 automatic | 37 mm | 46 mm | 150 m |
| Boldr Venture Automatic | £299 | Seiko NH35 automatic | 38 mm | 44 mm | 200 m |
| Seiko 5 Sports Field 36 (SRPJ85) | £290 | Seiko 4R36 automatic | 36.4 mm | 44.4 mm | 100 m |
| Hamilton Khaki Field Mechanical 36 | £595 | Hamilton H-50, hand-wound | 36 mm | 46 mm | 100 m |
* Baltic prices in euros; converted at the 26 October 2026 rate. Baltic says taxes and customs fees are not included on UK orders above €150.
Prices checked 8 November 2026. The Seiko price is from Watches of Switzerland; the Boldr price is from WatchGecko; the rest are from the brands' own sites.
The Clemence Munro and Baltic Tourer are the closest in spirit: compact, automatic, 150 m. The Boldr and Seiko are the value picks; note that the Seiko uses a domed Hardlex crystal rather than sapphire, and adds a day-date window. The 36 mm Hamilton keeps the classic look for smaller wrists. For a longer list, see the best field watches under £600, or the best British field watches if you would like to buy British.
Which should you buy?
- Buy the Hamilton Khaki Field Mechanical 38 if you want the reference field watch, enjoy winding, and won't swim in it.
- Buy the Khaki Field Auto 38 if you want the Hamilton look as an automatic with 80 hours, and can stretch to £640.
- Buy KOMPAS if you want a 39 mm automatic with 100 m, a time-only dial that reads in five-minute steps, and two straps in the box. Start with North or South.
Frequently asked questions
Is KOMPAS better than the Hamilton Khaki Field Mechanical?
Neither is better overall. The Hamilton Khaki Field Mechanical 38 (£545) is hand-wound with an 80-hour power reserve, 9.5 mm thick and rated to 50 m. KOMPAS (£535, our own brand) is automatic with about 42 hours of power reserve, 10.4 mm thick and rated to 100 m. Pick the Hamilton for the winding ritual and the classic look, KOMPAS for self-winding and swimming.
Is the Hamilton Khaki Field Mechanical automatic?
No. The Khaki Field Mechanical uses Hamilton's hand-wound H-50 calibre with an 80-hour power reserve, so you wind it by the crown. The automatic version is the Khaki Field Auto 38, which uses the H-10 calibre and costs £640 on leather in the UK.
Which is better for swimming, KOMPAS or the Khaki Field Mechanical?
KOMPAS. It is rated to 100 m, which covers swimming and snorkelling. The Hamilton Khaki Field Mechanical 38 is rated to 50 m, which Hamilton's own site lists as 5 bar, so it is better kept out of the pool.
Which wears smaller on the wrist?
They wear almost the same. The Hamilton is 38 mm with a 47 mm lug to lug; KOMPAS is 39 mm with a 46.5 mm lug to lug. The Hamilton is thinner, at 9.5 mm against 10.4 mm.
What are the best Hamilton Khaki Field alternatives under £600?
KOMPAS (£535), the Clemence Munro (from £549), the Baltic Hermétique Tourer (from €550), the Boldr Venture Automatic (£299) and the Seiko 5 Sports Field 36 (£290). Hamilton's own Khaki Field Mechanical 36 (£595) is the choice for smaller wrists.
Where is KOMPAS made?
KOMPAS is designed in Great Britain. It uses a Japanese Miyota 9039 automatic movement and is assembled in Hong Kong.
