Ring Size Guide: How to Measure Your Ring Size at Home
A fitting with a jeweller tends to give the most reliable ring size, but you can get a good estimate at home with a ring that already fits or a strip of paper. UK ring sizes use letters from A upwards, with half sizes in between, and most adult sizes fall between H and Z.
Ring sizes are defined by the inside circumference of the ring in millimetres. The international standard for this is ISO 8653:2016, and EU sizes are that circumference rounded to a whole millimetre. For the full list of UK letters with US and EU equivalents, use our UK ring size conversion chart or the ring sizing guide.
Two ways to measure at home
1. Use a ring that already fits
Measure the inside diameter of a ring that fits the same finger well, in millimetres, and compare it with the chart. If it sits between two sizes, choose the larger.
2. The paper strip method
Wrap a thin strip of paper around the base of your finger, mark where it overlaps, then measure the length in millimetres. Compare it with the chart. If you measure the inside diameter of a ring instead, multiply it by 3.14 to get the circumference. Make sure the ring slides over the knuckle.
Different jewellers publish slightly different millimetre values for the same letter, so the closest measurement in millimetres is more useful than the label alone.
Tips for an accurate result
- Measure at the end of the day when your fingers are warm.
- Avoid measuring when you are cold, as fingers shrink.
- Wide bands usually feel tighter, so you may need a half size larger.
- If your knuckle is larger than the base of your finger, measure both and choose a size in between.
Buying as a surprise?
Read how to find out your partner's ring size without ruining the surprise. If you are unsure, we can talk you through options during your bespoke journey.
Frequently asked questions
How do I convert a ring diameter to a UK size?
Measure the inside diameter in millimetres and multiply it by 3.14 to get the circumference, then find the closest circumference on our ring sizing chart.
What is the average ring size in the UK?
We have not found a reliable published figure for average UK ring sizes, so we would rather not guess. If the ring is a surprise, measuring a ring they already wear on the same finger is a better starting point than any average.
Can a ring be resized later?
Many plain and solitaire rings can be resized. If your ring needs resizing within 1 month of delivery, one resize by a local jeweller is reimbursed on a quote and receipt, with evidence. Eternity and pavé rings are more limited, so getting the size right first matters more for those styles.
What if I am between sizes?
Choose the larger size, especially for wider bands. A ring that is slightly loose can sometimes be fitted with a sizing aid.