How to Measure Your Ring Size at Home, Without a Sizer

Ordering a ring online comes down to one number, and getting it wrong costs a fortnight. This is the most reliable way to measure at home without a sizer, and the adjustments that matter once you have the number.

Method 1 — measure a ring she already wears

This is the most accurate method, because it measures the ring you are replacing rather than your estimate of a finger.

1. Take a ring that fits the intended finger well and is of a similar width to the one you are buying.
2. Lay it on a ruler and measure the inside diameter in millimetres — edge to edge across the widest part of the circle, not including the metal.
3. Match the millimetres to the size chart below.

Method 2 — string or paper

If there is no existing ring:

1. Cut a strip of paper about 5 mm wide, or use a length of thread with no stretch.
2. Wrap it around the base of the finger, snug but not tight — it should slide over the knuckle with a slight drag.
3. Mark where the ends meet, then measure that length in millimetres. That is the circumference.
4. Divide by 3.14 to get the diameter, then use the chart.

US ring size chart

US size	Inside diameter (mm)	Circumference (mm)
4.5	15.3	48.0
5	15.7	49.3
5.5	16.2	50.6
6	16.5	51.9
6.5	16.9	53.1
7	17.3	54.4
7.5	17.7	55.7
8	18.2	57.0
8.5	18.6	58.3

Four things that change the answer

• Measure at the end of the day. Fingers swell in the afternoon and in warm weather. A morning measurement is usually half a size small.
• Wide bands fit tighter. A band 6 mm or wider covers more finger and needs roughly a half size up from a thin band.
• Stacking needs room. If the ring will sit next to another one, size up half.
• Knuckles matter more than the finger. If the knuckle is much larger than the base, the ring has to pass it — measure both and choose the larger.

When to size up rather than down

Slightly loose is easier to live with than slightly tight. A ring that is half a size big can be worn on a warmer day, on a swollen finger, or with a thin guard ring. A ring that is half a size small cannot be worn at all, and sterling silver can only be stretched about one size before the setting is at risk.

Common questions

Can sterling silver be resized?

Yes — solid S925 can be sized up or down by a jeweller, usually about two sizes. Plated pieces generally cannot, because the heat destroys the finish. It is one of the practical reasons we work only in solid metal.

Which finger is a promise ring worn on?

There is no rule. Traditionally the ring finger of the right hand, but most people wear it wherever it sits comfortably and looks right.

What if I get it wrong?

Our returns page sets out the exchange window and the condition we need the piece back in.

Every ring in the sterling silver collection is listed in US sizes 4.5 to 8.5. Start with the First Promise.