Here are some helpful charts for necklaces, bracelets etc. from Fabucrafts in Woodbridge, Ontario
 Bead Size                       STRANDLENGTH

                            1"       4"     16"    20"    24"    28"    32"

• 3mm        8.46    33.8    136    170    204    237    272
• 4mm        6.35    25.4    102    127    153    178    204
• 5mm        5.08    20.32    82    102    125    143    164
• 6mm        4.23    16.9      68      84    101    118    136
• 7mm        3.62    14.4      58      70     86     101    116
• 8mm        3.17    12.68    51      64     76       89    102
• 10mm      2.54    10.16    41      51     61       71      82
• 12mm      2.11      8.44    34      42     51       59      68
• 14mm      1.81      7.24    29      36     43       50      58
• 16mm      1.58      6.32    25      32     38       44      50
• 18mm      1.41      5.64    23      28     34       39      46

• BRACELETS

  Bracelets

  What is the right bracelet length for you?

  Jewellery bracelets are beautiful and fun. But there is nothing quite as annoying as a bracelet that is too large or too small is there? Especially when you really love that bracelet ... oh, but only if it was the right size!
  
  People tend to either like their bracelets be a draping fit or a snugger fit.
  
  As a general rule, for a draping fit, bracelets should be about 2 to 2.5 cm larger than the measured circumference of the wrist.
  
  For a snug fit (doesn't drape onto the back of the hand), about 1.5 to 2 cm larger than the wrist circumference.
  
  To measure your wrist circumference, use a non-stretch tape measure, string, or ribbon. Place it around the widest part of the wrist (over the knobby part) - snugly but not too tight.

• NECKLACE

  Necklace

  What is the right necklace length for the occasion?

  Ever wondered about the lengths of necklaces? What lengths should you make? Are there guidelines or standards?
  
  The following information, compiled from various sources, will help you design just the length you need.

  
  

  Name	Length		Desc.	Comments
  	(inches)	(cm)
  collar choker	12-13"	31-33 cm	sits snugly at the middle of the neck	complements off-shoulder, v-neck, boat neck necklines
  choker	14-16"	36-41 cm	just on or above collarbone	a classic & versatile length.  Suits formal & informal wear
  princess	17-19"	43-48 cm	ends a little below collar bone	probably the most common length. Suits high and low necklines.
  matinee	20-25"	51-64 cm	ends just at top of bust	most popular of longer styles.  Complement low & highnecklines.  Formal & casual wear.
  opera	26-36"	66-91 cm	over bustline	versatile: can be worn in single strand or doubled over.  Can be knotted at neckline or above bust, etc.
  rope	37-45"	94-114 cm	long	tip: can be knotted and flung over shoulder
  lariat	48++ "	122++ cm	very long	like the rope, it usually has no clasp.  One end loops through the other.

Fabucraft