Does a 40 mm watch fit your wrist?

Watch sizes are quoted in millimetres, and the number means the width of the case, crown excluded. Forty millimetres has become the size most men buy, and it is also the size most often bought wrongly, because the number on its own says very little.

Measure the wrist first

Take a tape measure, or a strip of paper and a ruler, and go around the wrist where the watch will sit, just past the bone. Most men land between 16 and 20 centimetres.

Wrist	Case that reads right
15 to 16.5 cm	36 to 39 mm
16.5 to 18.5 cm	38 to 42 mm
18.5 to 20 cm	41 to 45 mm

A 40 mm case sits comfortably in the middle. On a 17 cm wrist it looks considered; on a 20 cm wrist it looks modest, which some men want; on a 15 cm wrist it takes over.

Three numbers that matter more than the width

Lug to lug. The distance from the top horn to the bottom one. This, not the case width, decides whether the watch overhangs the wrist. As a rule it should not exceed the flat part of your wrist.

Thickness. Under 12 mm slips under a shirt cuff. Above 14 mm it catches, and you will notice it every time you reach for something.

Strap width. Usually half the case width, give or take. A 40 mm case takes a 20 mm strap. A strap too narrow makes the head look bulbous.

The dial changes the size you see

Two watches of the same width can read differently. A wide bezel and a small dial opening make the watch look smaller; a thin bezel makes it look larger. A pale dial advances and looks bigger; a dark dial recedes and looks smaller. If you are between sizes, an ivory dial in 40 mm will wear like 41, and a black dial like 39.

Try it before the tape measure convinces you

Cut a strip of paper 40 mm wide, lay it across your wrist and look down as you would when checking the time. It is a crude test and it settles the question in ten seconds.

Where to start with LÖWE

The Rigi is the quartz chronograph, with a sun-and-moon display and a world-map counter. The Pilatus is the open-heart automatic, self-winding, with the balance wheel in plain sight. Both take a stainless steel case on a calf leather strap.

If you already own a watch that fits, measure its case across the dial and compare before ordering. And if the size turns out wrong, there are fourteen days to send it back.