How to Measure your Ring Size

diamond engagement ring on woman's hand

Measuring Your Ring Size at Home

What You Will Need

Using either a piece of string, floss or paper the ring finger circumference is measured. The widest point below the knuckle would be an ideal site to measure, ensuring the floss or string isn't wrapped to tightly as to restrict blood flow. If the size of your finger below the knuckle drastically differs in size from the knuckle itself, measure your knuckle as well and choose a size that falls more in the middle of these two measurements.


Take a piece of string or strip of paper no wider than 1.5cm, and wrap it around the base of the ring finger. Mark the string to record the circumference of the finger. Using a ruler measure the length of the string or paper in millimetres, and compare to the UK Ring Size Measurement Chart (below).

Top Tips:

  • Avoid measuring for a ring when you’re cold, as your fingers will be half a size smaller.
  • The evening is the best time of day to measure your finger, as this is when they are at their largest
  • Measure your finger at least 3 times to ensure the correct size reading.
  • Rings with wider bands will fit a bit tighter, so you may need to go up a size.
  • For accuracy have your ring size also measured with a gauge or ring sizer (see below)

Having your ring size measured by a Jeweller

ring size gauge in jewellers hand

Typically a ring sizer (pictured below), or gauge (above and main image) is used by a Jewellery professional to ascertain ring size. The finger of the wearer is measured an

Marked in whole and half sizes, a narrow gauge is used for narrow rings such as Solitaires (up to 4mm width), or tapered rings (within a width range of 2-7mm). Wide gauges are used to measure rings wider than 4mm. 

Rings that are convex on the interior fit surface have less metal in contact with the finger so need to be sized slightly smaller than the actual finger size. The size adjustment depends on the distance between the end of the shank and the opening. 

metal ring sizer close up

UK Ring Sizes - Conversion Table

solitaire diamond engagement ring

Below is a list of ring sizes and the corresponding measurement of finger circumference in millimetres:

A- 37.8mm ,B- 39.1mm, C- 40.4mm, D- 41.7mm, E- 42.9mm, F- 44.2mm, G – 45.5mm, H – 46.7mm, I  – 48mm, J – 48.7mm, K – 49.9mm, L – 51.2mm, M – 52.5mm, N – 53.8mm, O – 55mm, P – 56.3mm, Q – 57.6mm, R – 58.9mm,S – 60.1mm, T – 61.4mm, U – 62.7mm, V – 64mm, W – 65.2mm, X – 66.5mm

If you have any further queries or would like to come in for a ring sizing you can Contact Us or Book an Appointment