The easiest method is to borrow a ring she already wears on the correct finger and have it measured by a jeweller, or measure the inside diameter yourself and compare it to a ring size chart. Pick a ring you have seen on her ring finger, since finger sizes differ across the hand. If you cannot borrow one, ask a close friend or family member who may know her size, or note the size of a ring she owns by tracing its inside circle on paper. As a fallback, the average UK women's ring size is around L to N, and a ring can be resized after the proposal if it is slightly off. If you are buying a Luma engagement ring setting, our team can talk you through sizing and resizing during your consultation.
Book a consultation via our contact page if you want help navigating this without giving the surprise away.
The borrow and measure method
The most accurate approach. Take a ring she wears regularly on her ring finger (or as close to it as possible) into any jeweller and they can measure it on a finger sizer in under a minute. If you cannot get to a jeweller, measure the inside diameter with a ruler in millimetres and compare to a UK ring size chart. A diameter of 16.0mm is roughly size L, 16.5mm is M, 17.0mm is N.
The trace method
If you cannot borrow without her noticing, place one of her rings on paper and trace inside the band carefully with a sharpened pencil. Measure the diameter of the circle and compare to a size chart. Less accurate than measuring on a sizer but useful as a starting estimate.
Related questions
What is the average UK women's ring size?
L to N is the most common range, with M being roughly the midpoint. Always confirm by measuring rather than assuming.
What if the ring does not fit when you propose?
Not the end of the world. Most rings can be resized. Luma engagement rings include one free resize within 12 months of purchase, so a slightly off fit is a fixable problem rather than a lasting one.
Can you resize an eternity ring?
Full eternity rings cannot be resized because the diamonds run all the way around. Half eternity rings and solitaires can be resized within a reasonable range.
