Decreasing or increasing the waist width is often easy, as long as the adjustment is not too big. The most important thing is to make several smaller adjustments in different places, rather than one big adjustment in the same spot. 

INCREASING THE WAIST WIDTH

If you need to add 2 cm more in the waist, add 0,25 cm at the top of side back and front; that is 1 cm in total. Start the new line at seat or thigh level. Then make each dart 0,25 cm smaller on both sides, as shown in the sketch below. 

The dart can also be removed, which gives a large difference in waist width. A good distribution is 1 cm at the top of back and front side, plus 1 cm in total in each dart at back or removing them. Don’t forget to adjust the pocket pieces as well if needed, and to reshape the waistline if the dart has been removed. 

DECREASING THE WAIST WIDTH

To decrease the waist width, follow the same principles of distributing the adjustments but remove width instead.

The top of side can easily be made 1 cm smaller and the darts can be 0,5 cm wider on both sides. 1 cm can also be removed from CB seam.