Bracelets are sold by their length and bangles by their inside diameter, and neither is your wrist size. This page turns a wrist measurement into bracelet lengths for three fits and draws a closed bangle at true size, with the Indian sizes 2-0 to 2-14 most bangle sellers use.
Measure the wrist
Wrap a paper strip or soft tape just above the wrist bone, where a bracelet sits, not over a watch or a sleeve. Mark where it meets, then read the strip on any ruler or on the 1:1 ruler in the ring sizer. Most adult wrists measure 5½ to 8 inches (14 to 20 cm).
Add room for the fit you like
Jewellers’ size guides add a quarter to half an inch for a snug fit, half to three-quarters of an inch for a comfortable fit and three-quarters to one inch for a loose fit. A 6½" wrist therefore wears a 6¾–7" snug bracelet, a 7–7¼" comfortable one or a 7¼–7½" loose one. Thick chains and beads use up length on the inside, so take the upper end of the range for bracelets over about 5 mm thick.
Snug = wrist + ¼–½" · comfort = wrist + ½–¾" · loose = wrist + ¾–1"
Closed bangles go over the hand
A bangle without a clasp has to slide over the widest part of your hand, so your wrist size alone does not decide it. The reliable way is to measure a bangle that already fits: lay it flat on the 1:1 circle and match the inside edge. On a narrow phone the sides of a 60 mm circle run off the screen; the top and bottom arcs still measure the diameter.
Without a bangle, bring your thumb and little finger together as if putting one on and measure round the widest part of the hand; a bangle needs an inside circumference a little larger than that.
Cuffs, chains and charm bracelets
Open cuffs are sized by their inside length end to end plus the gap; they can be squeezed slightly to fit, so a cuff close to your wrist size plus about an inch usually works. Chain bracelets with an extender ring can be fastened shorter. Charm bracelets need the loose end of the range, because every charm takes up room on the inside and pulls the bracelet tighter as it hangs.
Indian bangle sizes
Indian sizes are written 2-2, 2-4 and so on. The second number is sixteenths of an inch over two inches of inside diameter, so 2-4 is 2 4/16" (2.25", 57.2 mm) and 2-8 is 2½" (63.5 mm). Most Indian jewellers publish this scale; one or two use different numbers, so check the millimetre value against your measurement.
Indian 2-N: inside Ø = 2 + N/16 inch · 2-2 = 54.0 mm · 2-6 = 60.3 mm · 2-10 = 66.7 mm