How to find your ring size at home

Ring sizing goes wrong more often than any other part of buying jewellery online, and almost always for the same handful of reasons. Ten minutes and a strip of paper will get you a size you can order with confidence.

Method one: measure a ring you already own

This is the most accurate method available at home. Take a ring that fits the finger you are buying for, lay it on a ruler, and measure straight across the inside from edge to edge. That measurement in millimetres is the inside diameter. A 17.3 mm inside diameter is roughly a UK size N, a US size 7. Measure twice: half a millimetre is most of a size.

Method two: the paper strip

• Cut a strip of paper about 5 mm wide — paper, not thread, which stretches and will read small.
• Wrap it around the base of the finger, snug but not tight, and mark where it overlaps.
• Measure the length in millimetres. That is the inside circumference. Divide by 3.14 for the diameter.
• Check it slides over your knuckle before you commit.

The three mistakes

First, measuring cold. Fingers shrink noticeably in cold weather and swell in heat — measure at the end of the day, at room temperature, when your hands are at their largest. Second, forgetting the knuckle: if your knuckle is wider than the base of the finger, size to the knuckle or the ring will not go on. Third, assuming both hands match. They rarely do; the dominant hand usually runs half a size larger.

When to size up

Size up for a wide band — anything above about 6 mm sits tighter than a thin one at the same nominal size. Size up if you are buying as a surprise and genuinely cannot check, since a ring that is slightly loose can be worn on another finger while a tight one cannot be worn at all. And size up for a ring intended for the winter months if you are measuring in summer.

If a ring does arrive wrong, our exchange window is 7 days from delivery — so check the fit as soon as it lands rather than saving it for the occasion.