Measure Ring Size

Fit and comfort

Ring fit around knuckles

For many people the knuckle, not the base of the finger, is the widest part — and a ring must pass the widest part to be worn at all. This guide covers measuring both points and handling a large gap between them.

Note: Measure at the knuckle and at the base, and size for the larger of the two. A ring sized only for the base will not pass a larger knuckle — and a ring sized for a much larger knuckle will spin at the base, which is a separate problem with its own fixes.
knucklebasering travels down, past the knuckle
If the knuckle is wider than the base, the ring must pass the knuckle — size for the larger of the two.

Measure both points

  1. Measure the base

    Wrap a flexible tape around the base of the finger, where the ring will sit, snugly in the evening. Record the circumference in millimetres.

  2. Measure the knuckle

    Wrap the tape around the widest part of the knuckle, with the finger straight. Record that circumference too. The knuckle reading is often 1–3 mm larger than the base reading — that is normal, not an error.

  3. Convert both, and take the larger

    Convert each circumference to a size. The ring size is the larger of the two results. Example: base 54.4 mm is US 7, knuckle 57.0 mm is US 8 — the ring size is US 8, because a US 7 ring cannot pass a US 8 knuckle.

  4. Check the gap

    If the two sizes are the same or within half a size, order the larger and the fit will usually be acceptable at the base too. If they differ by a full size or more, read the next section — a plain band in the knuckle size will spin at the base.

When the gap is large

Accept some spinning

For a casual ring, a half-size to a full size of spinning at the base is often tolerable, especially for a light band that is not top-heavy. Try the knuckle size first; if the spinning bothers you, move to the next option.

Sizing beads or a sizing aid

A jeweller can fit small beads or a bar inside the band that grip the base while still allowing the ring over the knuckle. This is the standard solution for a large knuckle-base gap, and it is reversible — unlike ordering a smaller ring that cannot be worn.

A hinged or adjustable shank

For valuable rings with a large gap, a hinged shank opens to pass the knuckle and closes at the base. This is a jeweller's job, not a home adjustment, and it is worth considering before committing to an expensive ring in a compromised size.

Common mistakes

  • Measuring only the base. The commonest knuckle error, and the one that produces a ring that cannot be worn at all.
  • Measuring the knuckle with a bent finger. A bent knuckle is wider than a straight one. Measure with the finger straight, as it will be when the ring goes on.
  • Ordering the average of the two sizes. The average passes neither test well: it may still not pass the knuckle, and it still spins at the base. Size for the knuckle, then fix the spinning separately.

Limitations

This guide assumes a normal, flexible knuckle joint. Arthritis, injury, or a joint that does not bend normally changes the problem: a ring that must pass a stiff or enlarged joint needs a jeweller's advice (hinged shanks and similar solutions exist) rather than a larger size alone.

Related guides

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