Measure a Bangle You Already Have
Step I : lose your fingers together and bring your thumb close to your little finger. Same as the position of putting the bangle.
Step II : Wrap a measuring tape or string of thread on the widest part of your hand as shown in the image.
Step III : Mark your size on the thread or on the measuring tape. This will be the circumference of your hand.
Step IV : Measure the thread or tape from mark to mark on scale and find your bangle circumference (in mm).