Jewelry sizes

Adults' Bracelets

Small                        7.0 inches (Small Woman’s Wrist)
Average                    7.5 inches (Medium Woman’s Wrist)
Large                        8.0 inches (Large Woman’s Wrist or Average Man’s Wrist)
X-Large                     8.5 inches (For man with larger wrist)

Kids' Bracelets

0-3 months                3.5 inches
3-6 months                4.0 inches
6-12 months              4.5 inches
12-24 months            5.0 inches
2-4 years                   5.5 inches
5-7 years                   6.0 inches
8-12 years                 6.5 inches

Kids' Necklaces

Toddler                       12 inches
Child                           14 inches (extender chain recommended)

Women's Necklaces

Collar                          12-13 inches
Choker                        14-16 inches
Princess                      17-19 inches
Matinee                      20-24 inches
Opera                         28-34 inches
Rope                            +45 inches

Men's Necklaces

Base of neck                 18 inches (for smaller neck sized)
To collarbone                20 inches (most common length for average sized men)  
Below the collarbone      22 inches
Just above the sternum  24 inches

Notes

Make your starting wire or thread about 6 inches longer than the size the project you are working on to allow for tying off the clasps.

Lobster Clasps add ¾ - 1” to your measurements
Toggle Clasp add 1 - 1 ¼” to your measurements