If you are measuring the wrist to get the correct size please use the 'inner circumference' measurement.
If you are measuring one of your existing bracelets, please use the 'length' measurement.
Inner circumference (including clasp):
medium - 19cm
large - 20.5cm
Length (including clasp):
medium - 20cm
large - 22cm
clasp - width 0.8cm x length 3cm