Bangle sizing in South India runs on a numbered scale — 2.4, 2.6, 2.8, 2.10 — where a larger number means a larger bangle. The number describes the bangle's internal diameter, and the fit test is whether it clears the widest part of your hand, not your wrist.
2.4 is the smallest of the common sizes and 2.10 the largest, with 2.6 and 2.8 between them. 2.6 and 2.8 are the most commonly bought adult sizes. Note that 2.10 is read as "two-ten", a step above 2.8 — it is not the same as 2.1.
Tuck your thumb into your palm as though you were sliding a bangle on, and press your hand into its narrowest shape. Wrap a strip of paper or a tape measure around the widest part of that shape — usually across the knuckle of the thumb — and mark where it overlaps. That measurement is the circumference your bangle has to pass over.
Divide the circumference by 3.14 to get the diameter you need, then pick the listed size closest to it. If you already own a bangle that fits, measuring its inside diameter across the middle is quicker and more reliable than measuring your hand.
Go up. A bangle that will not clear the knuckle cannot be worn at all, while a slightly loose bangle still sits and can be worn in a stack. This matters most for closed bangles, which have no adjustment; screw and openable designs are more forgiving.
Broad kada-style bangles and stone-set designs sit more snugly than thin plain bangles of the same nominal size, because the width limits how much the bangle can angle as it passes the knuckle. If you are buying a broad design and you are between sizes, size up.
2.6 and 2.8 are the most commonly bought adult sizes. 2.4 suits smaller hands and 2.10 larger ones.
Yes. The scale reads 2.4, 2.6, 2.8, then 2.10 — "two-ten" is the largest of the four, not a size between 2.0 and 2.2.
Tuck your thumb into your palm, wrap a paper strip around the widest part of your hand, mark the overlap, and divide that circumference by 3.14 to get the diameter. Match it to the closest listed size, rounding up if you are between two.