Section Two
Size & Fit
尺码与合身
The methodology of measurement and the structural limits of sizing systems. This page gives reproducible measuring steps and explains why a nominal size cannot be carried across brands.
§ 1Definition and Scope
Definition
Fit on this page means that, without producing sustained pressure pain, the fabric holds a stable position at the areas where support is required. Comfort and stability form a pair of competing constraints, so no solution maximises both at once; the position taken must follow the intended use.
This page discusses measuring methods and the properties of sizing systems themselves. Which size a given person should choose depends on the pattern of a particular garment, and lies outside the range of questions to which this page can give a single answer.
§ 2Reproducible Measuring Methods
The point of measuring is not what a single measurement yields, but that every measurement yields the same figure. The four measurements below cover the sizing basis of the great majority of next-to-skin garments.
| Measurement | Method | Principal sources of error |
|---|---|---|
| Underband | Measure horizontally around the lower edge of the ribcage, close to the skin but without pressing in | Tape not held level; measuring while inhaling |
| Bust | Measure horizontally around the fullest part of the breasts without compressing the tissue | Arms not relaxed at the sides; tape drawn so tight that it flattens the tissue |
| Waist | Measure horizontally around the narrowest part of the waist | Drawing the abdomen in; measuring after a meal |
| Hip | Measure horizontally around the fullest part of the hips | Tape lower at the front than at the back, so that it is not level |
Practice notes
- Measure standing sideways to a mirror, so that you can see whether the tape is level.
- Take three consecutive measurements at each point and record the middle value rather than the average.
- Read the value at the end of a normal exhalation; avoid holding the breath or inhaling deeply.
- Record the result in centimetres, and do not convert it into a letter size on the spot.
§ 3Structural Limits of Sizing Systems
- A size is an interval, not a point. Products labelled with the same size can differ in actual dimensions by more than a full size. Carrying a nominal size across brands therefore does not hold methodologically, and measured centimetres should be used instead.
- The add-four-inches rule does not apply to modern elastic fabrics. The rule derives from a period in the mid-twentieth century when elastic materials were not yet well developed, and its function at that time was to compensate for the limited extensibility of fabric. Carrying the rule over to contemporary fabrics containing elastane systematically yields a band that is too large.
- Cup size cannot be discussed apart from the band. The cup corresponds to the difference between the bust and the underband, and an identical difference corresponds to a different tissue volume at different bands. A D cup therefore does not denote the same thing at two band sizes.
- Sizing systems in different regions are not interchangeable. The same body dimensions are expressed differently in different systems, and conversion tables differ among themselves. The error introduced by converting between systems is usually greater than that of selecting directly from measured centimetres.
§ 4Common Misconceptions
| Misconception | Explanation |
|---|---|
| Cup size changes linearly with body weight | The ribcage and the breast tissue do not respond in the same way. As weight changes, the band and the cup may move in opposite directions, or one may change while the other does not. |
| The tighter the band, the better the support | Support arises from the interaction of the band and the cup, not from tightness alone. An excessively tight band produces marks, restricts breathing and causes skin discomfort, and does not increase effective support. |
| A garment that feels tight in the fitting will loosen with wear | Some stress relaxation does occur, but its extent is limited and is not sufficient to compensate for a size that is clearly too small. The criterion should be the absence of pain in the initial state. |
| A slipping strap means the strap is too loose | A slipping strap is more often related to a band that is too loose or a cup that does not match. Tightening the strap alone transfers the load to the shoulder and may, over time, cause marks and discomfort in the neck and shoulder. |
| Once measured, there is no need to measure again | Body dimensions change with weight, cycle and age. Remeasuring every six to twelve months is preferable to relying on remembered figures. |
§ 5Editorial Note and Outstanding Work
Not yet completed
- An item-by-item comparison of the principal sizing systems, with the conversion error quantified
- The effect of different cup constructions, such as the full cup and the three-quarter cup, on the choice of size
- The differing response of the underband and the cup to changes in body weight, and its anthropometric basis
Notes on This Page
- Editorial principle: the section on measurement gives reproducible steps; the section on sizing systems states only structural facts and gives no brand-specific sizing advice.
- Measuring terminology follows the general definitions of anthropometry. This page does not involve medical judgement.
- If pain, marks or skin damage persist, consult a clinician rather than adjusting size.
- Factual errors may be reported to hello@beyiji.com.