Most of the bracelets will stretch somewhat and most people's hands can be squeezed a little bit so you can pick a slip-on size that is the same or slightly smaller than your measurement and squeeze into the bracelet.
If you want a nylon bracelet in a reduced circumference from the "slip-on" size you will need to pull some slack from the knot. Read on...
A few of the offerings in the WhatKnotShop online shops are labeled “adjustable”. This means that the bracelet has been fully completed but has not been tied off or worked up to the smallest possible circumference. Adjustable bracelets enables the buyer to adjust the final size of the bracelet to a comfortable fit by removing the excess slack in the knot. This is known as “working up” the knot to it’s final shape. This link describes how to "work up" a turks head bracelet: http://bit.ly/cQpLED
This process can take some time as it involves pulling loops of cord around the weave of the knot in a progressive pattern until the slack comes out in one of the two loose ends. Loose made cotton bracelets can be worked up by this method to fit over a large hand and then fitted to a skinny wrist. This is the only practical way to get a custom for for a nylon or polyester material.
Visit the online shops to see what is available in your size:
If you don't find a pre-made design in your size please make a custom request! Due to the variety of designs not all sizes are stocked but most can be made within a very short time.