Ring size guide
UK ring size chart & guide
Find your size in two minutes: measure on your phone, read the full UK, US and EU chart, or print the A4 sizer. Wrong size? Swapping is quick and easy.
- Men's Active
- Sizes 7–14 · 8.7 mm
- Women's slim
- 5–10 Active · 4–10 Flow
- Between sizes
- Go down
- Swap
- Free · 30 days
The short answer
UK ring sizes run from A to Z, then Z+1 to Z+6. Each letter adds about 1.25 mm to the inside circumference: a UK N is 54.0 mm round (17.2 mm across), a UK T is 61.5 mm (19.6 mm). Measure the inside of a ring that fits, or wrap a paper strip round your finger, then read your size off the chart below.
- Most-bought men’s size
- 10UK T–U · 19.8 mm
- Most-bought women’s size
- 6UK L–M · 16.5 mm
- Between sizes?
- Go downSilicone fits snug
01 · Phone sizer
Your size, from your phone.
Calibrate the screen with any bank card, then drop a ring you own on it, or use a strip of paper. No ring? We'll predict it. Wrong size? Swapping is quick and easy.
Step 1 · Calibrate. Hold a £1 coin on the screen and drag the handle until the circle matches it.
Not calibratedStep 2 · Place a ring that fits the right finger on the screen. Drag the handle until the circle sits exactly on the ring's inside edge.
- Cut a strip of paper about 5 mm wide.
- Wrap it round the base of the finger — over the knuckle if the knuckle is bigger.
- Mark where it overlaps, then lay it on the ruler below with the end at 0.
No ring, no paper? We'll estimate from a few things about you. Expect ±1 size, and swaps are quick and easy.
Full size chartbotthms · UK letter · inside diameter · circumference
| botthms | UK | Inside Ø | Circumference |
|---|---|---|---|
| 4 | H-I | 14.9 mm | 46.8 mm |
| 5 | J-K | 15.7 mm | 49.3 mm |
| 6 | L-M | 16.5 mm | 51.8 mm |
| 7 | N-O | 17.3 mm | 54.3 mm |
| 8 | P-Q | 18.2 mm | 57.2 mm |
| 9 | R-S | 18.95 mm | 59.5 mm |
| 10 | T-U | 19.8 mm | 62.2 mm |
| 11 | V-W | 20.6 mm | 64.7 mm |
| 12 | X-Y | 21.4 mm | 67.2 mm |
| 13 | Z | 22.2 mm | 69.7 mm |
| 14 | Z+2 | 23.0 mm | 72.3 mm |
02 · Size chart
UK ring size chart: letters, US, EU and millimetres
Every UK letter from A to Z+6 with the matching US and EU size, the inside diameter and inside circumference, and the botthms size it corresponds to. Shaded rows are the sizes we make.
| UK | US | EU | Diameter mm | Circumf. mm | botthms |
|---|---|---|---|---|---|
| A | ½ | 38 | 12.0 | 37.8 | — |
| B | 1 | 39 | 12.4 | 39.0 | — |
| C | 1½ | 40 | 12.8 | 40.3 | — |
| D | 2 | 42 | 13.2 | 41.5 | — |
| E | 2½ | 43 | 13.6 | 42.8 | — |
| F | 3 | 44 | 14.0 | 44.0 | — |
| G | 3½ | 45 | 14.4 | 45.3 | — |
| H | 4 | 47 | 14.8 | 46.5 | 4 |
| I | 4½ | 48 | 15.2 | 47.8 | 4 |
| J | 5 | 49 | 15.6 | 49.0 | 5 |
| K | 5½ | 50 | 16.0 | 50.3 | 5 |
| L | 6 | 52 | 16.4 | 51.5 | 6 |
| M | 6¼ | 53 | 16.8 | 52.8 | 6 |
| N | 6¾ | 54 | 17.2 | 54.0 | 7 |
| O | 7¼ | 55 | 17.6 | 55.3 | 7 |
| P | 7¾ | 57 | 18.0 | 56.5 | 8 |
| Q | 8¼ | 58 | 18.4 | 57.8 | 8 |
| R | 8¾ | 59 | 18.8 | 59.0 | 9 |
| S | 9¼ | 60 | 19.2 | 60.3 | 9 |
| T | 9¾ | 62 | 19.6 | 61.5 | 10 |
| U | 10¼ | 63 | 20.0 | 62.8 | 10 |
| V | 10¾ | 64 | 20.4 | 64.0 | 11 |
| W | 11¼ | 65 | 20.8 | 65.3 | 11 |
| X | 11¾ | 67 | 21.2 | 66.5 | 12 |
| Y | 12¼ | 68 | 21.6 | 67.8 | 12 |
| Z | 12¾ | 69 | 22.0 | 69.0 | 13 |
| Z+1 | 13¼ | 70 | 22.4 | 70.3 | 13 |
| Z+2 | 13¾ | 72 | 22.8 | 71.5 | 14 |
| Z+3 | 14¼ | 73 | 23.2 | 72.8 | 14 |
| Z+4 | 14¾ | 74 | 23.6 | 74.0 | — |
| Z+5 | 15¼ | 75 | 24.0 | 75.3 | — |
| Z+6 | 15¾ | 77 | 24.4 | 76.5 | — |
How the chart works. UK sizes follow British Standard BS 6820: size A is 37.8 mm round the inside and every letter adds 1.25 mm. EU sizes (ISO 8653) are simply the inside circumference in millimetres. botthms sizes use US numbering, so a botthms 9 is a US 9.
Half sizes. A UK half size (N½, say) adds about 0.6 mm round. Silicone stretches a little, so if you measure a half size, order the whole size below it.
Ranges. Men’s 8.7 mm Active bands: sizes 7–14. Women’s slim 5.7 mm bands: Active 5–10, Flow 4–10.
03 · Measure at home
How to measure your ring size at home
Three ways that work without a jeweller. Each takes about two minutes. Do it at the end of the day, on the finger you will wear the ring on.
-
Method A · most accurate
Measure a ring that fits
- Take a ring that fits the right finger.
- Lay it on a ruler and measure the inside diameter, edge to edge, at the widest point.
- Find that number in the Diameter column. Half a millimetre is half a size, so be precise.
-
Method B · no ring needed
Wrap a strip of paper
- Cut a strip of paper about 5 mm wide and 10 cm long. Not string: it stretches.
- Wrap it round the base of the finger, snug but not tight, and mark where it overlaps.
- Measure from the end to the mark in mm. That is your circumference: find it in the Circumference column. Do it twice.
-
Method C · print it
Use the printable sizer
- Download the A4 sizer and print at 100% (“Actual size”).
- Check the 50 mm line with a ruler, or a bank card against the outline.
- Lay a ring on the circles, or cut out the strip sizer and wrap it round your finger.
04 · Our data
The ring sizes botthms customers actually buy
From 11,689 single silicone rings ordered on botthms.com between January 2024 and October 2026. Men’s sizes 9 to 11 make up 57% of men’s orders; women’s 5 to 7 make up 68% of women’s.
Share of single rings by size ordered, per range. Packs and double sets are excluded because they hold one size for several rings. Sizes are what people ordered, before any exchanges.
05 · Silicone is different
Sizing a silicone ring: four rules
A silicone ring stretches on and settles over the first few days. Size it like a metal ring and it will feel loose by the end of the week.
- 01
Between sizes, go down
Snug on day one is right. Comfortable on day one is too big. If you lift or do a job where the ring gets pulled, go down too: a snug ring stays put under a bar.
- 02
Measure late in the day
Fingers swell with heat, exercise and the day itself. A size taken on a cold morning reads small by teatime.
- 03
Mind the knuckle
Measure the base and the knuckle. If the knuckle is more than about 1 mm bigger, choose a size between the two, closer to the base. Silicone stretches over a knuckle more easily than metal.
- 04
Wide feels tighter
Our men’s band is 8.7 mm wide, the women’s slim band 5.7 mm. A wide band sits on more skin and feels about half a size tighter than a narrow one of the same size.
06 · Printable ring sizer
Print it, check it, measure.
A two-page A4 PDF: ring circles for every botthms size, a cut-out strip sizer and the full UK chart. Free, no sign-up.
- Print at 100%, “Actual size”, never “Fit to page”.
- Check the 50 mm line with a ruler before you measure.
- Still unsure? Order your best guess: size swaps are quick and easy.
07 · Questions
Ring size questions, answered.
What ring size am I?
Measure the inside diameter of a ring that fits, or wrap a strip of paper round the base of your finger and measure the length to where it overlaps. Find that number in the chart above to get your UK letter, US and EU size. Or use the phone sizer at the top of this page.
What is the average ring size in the UK?
Across 11,689 rings ordered on botthms.com since January 2024, the most common men's sizes are 10 (UK T–U) and 9 (UK R–S), and the most common women's sizes are 6 (UK L–M) and 5 (UK J–K). Averages are only a starting point: measure if you can.
How do I convert a US ring size to a UK size?
Each US size is about two UK letters. US 7 is roughly UK N½, US 8 is P½, US 9 is R½ and US 10 is T½. The chart above lists every UK letter from A to Z+6 with its US equivalent.
What is a UK size L in US and EU sizes?
A UK L is a US 6 and an EU 52, with an inside diameter of about 16.4 mm. That matches a botthms size 6.
How can I measure my ring size without a ring?
Cut a strip of paper about 5 mm wide, wrap it snugly round the base of your finger, mark the overlap and measure it in millimetres. That is your circumference: find it in the Circumference column. Don't use string, it stretches and reads too big.
Should I size up or down for a silicone ring?
Down. Silicone stretches on and settles over the first few days, so a ring that feels comfortable on day one will feel loose by the end of the week. If you are between two sizes, choose the smaller.
Does ring size change during the day?
Yes. Fingers are larger in the evening, in warm weather and after exercise, and smaller when you are cold. Measure at the end of the day for the most reliable reading.
What do botthms size numbers mean?
botthms sizes use US numbering, so a botthms 9 is a US 9 (about 19.0 mm across, UK R–S). Men's Active bands come in sizes 7–14; women's slim bands in 5–10 (Active) and 4–10 (Flow).
Do Ireland and Australia use the same sizes as the UK?
Yes, both use the UK letter system, so this chart works for Irish and Australian sizes too. Most of Europe uses EU sizes, which are the inside circumference in millimetres.
What if I order the wrong size?
Size swaps are quick and easy within 30 days. Start it from our returns page and we email you a label.
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