Everything here is a number the trade already uses. Where a figure is a standard it is named as one, and where it is a rule of thumb that is said too.
It is invoked constantly in fashion and almost always in the wrong place. Here is where it is genuinely true.
| landmark | fraction of height | nearest φ value | apart by |
|---|---|---|---|
| natural waist | 0.620 | 1/φ = 0.618 | 0.3% |
| mid thigh | 0.390 | 1/φ² = 0.382 | 2.1% |
| knee | 0.270 | — | — |
| shoulder | 0.818 | — | — |
On a body of 160 cm the golden point falls at 98.9 cm from the floor. The natural waist sits at 99.5 cm. They are 0.6 cm apart. That is why a high waist reads as proportioned, and why the myth persists.
Stylists divide a look one third to two thirds rather than in half, because an even split shortens the figure.
| division | at 160 cm | what sits there |
|---|---|---|
| a third from the floor | 53.3 cm | upper calf — a midi hem |
| two thirds | 106.7 cm | above the natural waist — a high waistband |
| golden, 1/φ | 98.9 cm | the natural waist itself |
| golden, 1/φ² | 61.1 cm | mid thigh — a short hem |
Why both survive. They land within a few centimetres of each other on most bodies, so either can be invoked afterwards to explain why something looked right. Thirds is the useful one, because you can find it in your head.
European sizes step by four centimetres in bust, waist and hip. That part is a standard. Length is not.
| size | bust | waist | hip | step |
|---|---|---|---|---|
| EU 34 | 82 | 64 | 88 | — |
| EU 36 | 86 | 68 | 92 | +4 |
| EU 38 | 90 | 72 | 96 | +4 |
| EU 40 | 94 | 76 | 100 | +4 |
| EU 42 | 98 | 80 | 104 | +4 |
| EU 44 | 102 | 84 | 108 | +4 |
The consequence. A range graded 34 to 44 spans twenty centimetres of body circumference and frequently zero centimetres of length. Every customer in that range receives the same hem.
The most misunderstood number in online sizing. A chart listing body measurements and one listing garment measurements can differ by fifteen centimetres and both be correct.
| cut | ease at the bust | ease at the hip | what it does |
|---|---|---|---|
| negative | −2 to 0 cm | −4 to 0 cm | only possible with stretch |
| close | 0 to 4 cm | 0 to 4 cm | follows the body, restricts a little |
| standard | 5 to 8 cm | 4 to 8 cm | the default for a woven |
| relaxed | 9 to 15 cm | 8 to 14 cm | hangs away from the body |
| oversized | 16 cm and up | 15 cm and up | the volume is the design |
Trade rules of thumb rather than a standard. They vary by house and by category.
Elastane does not make a garment run large. It lets a smaller flat measurement fit a larger body, because the cloth supplies the movement that ease would otherwise provide. That is a different thing.
| elastane | usable give in wear | can you size down | what it will not fix |
|---|---|---|---|
| 0 to 1% | almost none | no — size for the widest measurement | anything |
| 2 to 3% | 3 to 5 cm at the hip | if you are between sizes, yes | length, shoulders, rise |
| 4 to 6% | 6 to 10 cm | usually, and you should if you want it fitted | length, shoulders, rise |
| 7% and up | 10 cm and more | yes — it will relax with wear | length, shoulders, rise |
Stretch is a circumference solution and nothing else. You can take a 36 in a stretch trouser and still receive a 36 inseam and a 36 rise on a body that needs a 38 in both.
A woven cloth barely extends along either thread. Cut at 45° to both it extends by five to ten times as much and falls in a spiral. This is geometry, not chemistry: it is the angle at which both thread systems are equally oblique.
| direction of cut | extension in a plain weave | behaviour |
|---|---|---|
| warp, along the grain | 2 to 5% | holds its length, hangs straight |
| weft, across the grain | 3 to 6% | a little softer |
| bias, at 45° | 15 to 30% | clings, elongates, drapes in a spiral |
The Cusick test drapes a circle of cloth over a disc and measures the shadow it casts. The coefficient is the ratio of that shadow to the flat circle. Lower means more fluid. A real laboratory number that almost no brand publishes.
| cloth | drape coefficient | reads as |
|---|---|---|
| silk chiffon, fine viscose | 20 to 35% | fluid, follows the body |
| crepe, soft twill | 35 to 55% | falls close, some volume |
| cotton poplin, gabardine | 55 to 75% | holds its own shape |
| denim, canvas, heavy linen | 75 to 95% | stands away from the body |
Body-type geometry. Pear, hourglass, apple. Useful shorthand for the relationship between three measurements, and nothing more. There is no equation underneath it.
Universal proportion systems. Le Corbusier’s Modulor is architecture, not tailoring, and it was built on a 183 cm man.
The eight-head figure. A drawing convention. A real adult is about seven and a half heads tall; fashion illustration stretches to eight or nine to flatter the line. A rendering choice mistaken for anatomy for a century.