Ring Size Guide

Every ring we make is crafted to your size at no extra cost. UK letter sizes are what we work in, and the chart below converts to US and EU if that is what you know. You can do all of this at home — you do not need to go anywhere to be measured.

The quickest way: measure a ring they already wear

This is the most reliable method that costs nothing, and it does not spoil a surprise.

1. Take a ring that fits the correct finger comfortably.
2. Lay it flat and measure straight across the inside of the band, edge to edge, in millimetres.
3. Find that measurement in the Inside diameter column below.

A ruler works, but a digital caliper is far more accurate if you can borrow one.

The surest way: let us post you a strap sizer

A strap sizer is an adjustable band marked in UK letter sizes. You slide it onto the finger, ease it closed until it sits the way a ring should, and read your size off the window. One tool covers the whole range, and it lets you feel how a ring will actually pass the knuckle — which a paper strip cannot.

We will send you one. Order a strap sizer and we post it the next working day, first class. It is £5 at checkout, and we email the full £5 back to you as credit the moment your order is paid. The credit does not expire, and it stacks with any other offer — including your first-order discount — so it comes straight off the price of your ring.

A strap sizer is only as good as the tension you put on it, so three things make the difference between a right answer and a wrong one:

• Do not pull it tight. Close it until it is snug and no further. Over-tightening is the commonest reason people end up half a size too small.
• Check it comes back off over the knuckle. A ring has to pass the knuckle every time it is worn.
• Measure late in the day, with warm hands.

If you have a few days before you order, this is the method we would choose.

Measuring the finger itself

1. Cut a thin strip of paper about 5mm wide.
2. Wrap it around the base of the finger — snug, but loose enough to slide over the knuckle.
3. Mark where the paper overlaps, unwrap it, and measure to the mark in millimetres.
4. That number is the Inside circumference. Find it in the chart.

Four things that change the answer

• Time of day. Fingers are smallest first thing in the morning and largest in the evening. Measure late in the day.
• Temperature. Cold fingers shrink. Never measure with cold hands.
• Knuckles. If the knuckle is much wider than the base of the finger, size for the knuckle — the ring has to get over it.
• Wide bands. A band over about 6mm wide feels tighter. Go up half a size.

If you fall between two sizes, choose the larger one. A ring that is slightly loose can be worn; one that will not pass the knuckle cannot.

UK to US and EU conversion chart

Sizes are given by inside circumference, which is the measurement that does not vary between charts. EU sizes are simply the inside circumference in millimetres.

UK	US (nearest)	EU	Inside circumference	Inside diameter
F	3	44	44.2 mm	14.1 mm
G	3½	45	45.5 mm	14.5 mm
H	4	47	46.8 mm	14.9 mm
I	4½	48	48.0 mm	15.3 mm
J	4¾	49	48.7 mm	15.5 mm
K	5¼	50	50.0 mm	15.9 mm
L	5¾	51	51.2 mm	16.3 mm
M	6¼	52	52.5 mm	16.7 mm
N	6¾	54	53.8 mm	17.1 mm
O	7¼	55	55.1 mm	17.5 mm
P	7¾	56	56.3 mm	17.9 mm
Q	8¼	58	57.6 mm	18.3 mm
R	8¾	59	58.9 mm	18.8 mm
S	9¼	60	60.2 mm	19.2 mm
T	9¾	61	61.4 mm	19.5 mm
U	10¼	63	62.7 mm	20.0 mm
V	10¾	64	64.0 mm	20.4 mm
W	11¼	65	65.3 mm	20.8 mm
X	11¾	67	66.6 mm	21.2 mm
Y	12¼	68	67.9 mm	21.6 mm
Z	12¾	69	69.1 mm	22.0 mm

Half sizes (J½, N½ and so on) sit exactly halfway between the letters and are available on every ring — each half step is about 0.6mm of circumference.

UK and US scales do not line up exactly, so the US column is the nearest equivalent rather than a perfect match. If you only know your US size and want to be certain, email us the number and we will confirm the UK letter before we make anything.

Still not sure?

Do not guess on an engagement ring. You have two options:

• Order a strap sizer and measure properly at home. The £5 comes straight back to you as credit.
• Email info@thelabjewellers.com with what you know — a diameter, a US size, or the ring you measured — and we will work it out with you. We reply personally, within two working days.

Because every piece is made to order in your chosen size, getting this right before you order saves the most time. Nothing goes into production until your size is confirmed in writing. If a ring does arrive and the fit is wrong, contact us and we will talk you through the options.