In order for a garment to be functional, the pattern dimensions must be slightly larger than the body measurements. The added measure is called ease and its value can vary greatly depending on the desired look.
The wearing ease is sufficient to allow the body to move while keeping a very close fitted garment. Whether it is for a woman, a man or a child, this measurement is always 3cm. This measurement is not random – it is based on the PI number, or 3.1416... This number multiplied by the diameter determines the circumference of a circle (in our case, bust, waist, hip circumference…). If you thought you could avoid some mathematics when sewing...
Beyond 3cm, any added ease will be used to change the style of the garment. It is difficult to determine each type of ease, however, you can refer to the chart below as a guide. Note that the measurements mentioned below are to be added to a circumference!
Adjusted fit: 4.5cm
Loose fit: 10cm
Veryloose fit: 15cm and more...
Here it is the opposite, the value is removed from body measurements to compensate for the fabric elasticity, namely, stretch denim or jerseys. Negative ease cannot be used with woven fabrics because you will not be able to put on the garment as it won’t stretch.
Of course, a garment can include several types of ease to change its silhouette. For instance, an A-line dress is fitted to the bust, then gradually widens to the bottom so as to have a loose fit around the hip.