How to find your ring size at home
Finding your ring size at home is straightforward when you measure carefully. You can measure the inside diameter of a ring you already own or measure the circumference of your finger, then use our UK and US ring size chart to find the closest fit.
Measure the exact finger you will wear the ring on, at the end of the day, when your hands are warm. Measure two or three times before choosing a size.
How to measure your ring size
Measure an existing ring
Choose a ring that already fits the correct finger. Measure straight across the inside of the ring at its widest point, from inner edge to inner edge. This is the internal diameter. Match that figure to the chart below.
Measure your finger
Wrap a thin strip of paper or non-stretch string around the base of your finger. Mark where the ends meet, lay it flat, and measure the length in millimetres. This is your finger circumference.
Tips for getting the right fit
- Measure when your hands are warm. Cold fingers can be up to half a size smaller.
- Check the knuckle. If your knuckle is wider than the base of your finger, measure both and choose a size between the two.
- Allow for band width. Bands wider than 6 mm usually feel tighter; consider going up half a size.
- Do not pull string tightly. It should fit as comfortably as you want the ring to fit.
- Measure the correct hand. The same finger can differ in size between your left and right hands.
- Between sizes? Choose the larger size for comfort.
Ring size conversion chart
Use internal diameter when measuring an existing ring, or finger circumference when measuring your finger. This chart converts US ring sizes to their closest UK ring size and millimetre measurement. UK conversions are approximate because UK and US size intervals differ slightly.
| US size | UK size | Inside diameter | Finger circumference |
|---|---|---|---|
| 3 | F | 14.1 mm | 44.2 mm |
| 3.5 | G | 14.5 mm | 45.5 mm |
| 4 | H | 14.9 mm | 46.8 mm |
| 4.5 | I | 15.3 mm | 48.0 mm |
| 5 | J | 15.7 mm | 49.3 mm |
| 5.5 | K | 16.1 mm | 50.6 mm |
| 6 | L | 16.5 mm | 51.9 mm |
| 6.5 | M | 16.9 mm | 53.1 mm |
| 7 | N | 17.3 mm | 54.4 mm |
| 7.5 | O | 17.7 mm | 55.7 mm |
| 8 | P | 18.1 mm | 57.0 mm |
| 8.5 | Q | 18.5 mm | 58.3 mm |
| 9 | R | 18.9 mm | 59.5 mm |
| 9.5 | S | 19.4 mm | 60.8 mm |
| 10 | T | 19.8 mm | 62.1 mm |
| 10.5 | U | 20.2 mm | 63.4 mm |
| 11 | V | 20.6 mm | 64.6 mm |
| 11.5 | W | 21.0 mm | 65.9 mm |
| 12 | X | 21.4 mm | 67.2 mm |
| 13 | Z | 22.2 mm | 69.7 mm |
Understanding UK and US ring sizes
UK ring sizes use letters, while US ring sizes use numbers and half sizes. For example, a US size 7 is approximately a UK size N, with an inside diameter of 17.3 mm. The diameter and circumference columns are the most reliable way to compare sizing systems because they use direct millimetre measurements.
Our rings show the available size system on each product page. If a ring is listed in US sizes, use the conversion chart above to find the closest equivalent to your usual UK ring size.
Borrow a ring they wear on the same finger and measure its internal diameter. Fingers on the opposite hand may not be the same size.
How should a ring fit?
A correctly sized ring should feel secure at the base of your finger but should not leave a deep mark or restrict movement. It should pass over your knuckle with gentle resistance, rather than slipping straight off or needing to be forced. Remember that fingers naturally swell slightly in warm weather, after exercise and later in the day.
Frequently asked questions
What if my measurement falls between two sizes?
Choose the larger size. A slightly loose ring is generally more comfortable than one that is too tight, especially in warmer weather.
Does ring width affect sizing?
Yes. A wide band covers more of the finger and tends to feel tighter than a fine band. For bands over 6 mm wide, going up half a size is often more comfortable.
Can I use a phone screen or printable chart?
Screen and printer scaling can change measurements, so a ruler marked in millimetres is more dependable. A jeweller's ring sizer gives the most accurate result.
Still unsure?
Contact us with your measurement and the ring you are considering. Our team will help you select the closest available size.