Convert UK (uk) to US (us) instantly. UK ring size to US ring size conversion.
| Unit | Name | Value |
|---|---|---|
| us | US / Canada | — |
| eu | EU / Germany | — |
| mm | Circumference (mm) | — |
💡 Tip: Measure your finger circumference in mm — EU size = circumference in mm exactly. Divide by π (3.14159) to get diameter.
All standard sizes — with finger circumference and diameter for reference
| UK / Australia | US / Canada | Measurement |
|---|---|---|
| F | 3 | 44.2 mm circ / 14.1 mm dia |
| G | 3.5 | 45.5 mm circ / 14.5 mm dia |
| H | 4 | 46.8 mm circ / 14.9 mm dia |
| I | 4.5 | 48.0 mm circ / 15.3 mm dia |
| J | 5 | 49.3 mm circ / 15.7 mm dia |
| K | 5.5 | 50.6 mm circ / 16.1 mm dia |
| L | 6 | 51.9 mm circ / 16.5 mm dia |
| M | 6.5 | 53.1 mm circ / 16.9 mm dia |
| N | 7 | 54.4 mm circ / 17.3 mm dia |
| O | 7.5 | 55.7 mm circ / 17.7 mm dia |
| P | 8 | 57.0 mm circ / 18.1 mm dia |
| Q | 8.5 | 58.3 mm circ / 18.6 mm dia |
| R | 9 | 59.5 mm circ / 18.9 mm dia |
| S | 9.5 | 60.8 mm circ / 19.4 mm dia |
| T | 10 | 62.1 mm circ / 19.8 mm dia |
| U | 10.5 | 63.4 mm circ / 20.2 mm dia |
| V | 11 | 64.6 mm circ / 20.6 mm dia |
| X | 12 | 67.2 mm circ / 21.4 mm dia |
| Z | 13 | 69.7 mm circ / 22.2 mm dia |
Letter position ÷ 2 ≈ US size (rough). Use chart.
UK L = US 6; UK N = US 7; UK P = US 8; UK R = US 9; UK T = US 10.
Women: UK J–P (US 5–8). Men: UK P–V (US 8–11).
Converts UK / Australia ring size to US / Canada when purchasing from international online jewellers.
Converts customer-provided ring sizes to the sizing system used by their tools and ring blanks.
Converts a partner's known ring size to the size system used by an international jeweller.
Compares ring sizes from different measurement methods before placing a custom order.
Lists ring sizes in multiple systems on product pages for international customers.
Finds the correct local ring size equivalent when shopping for jewellery abroad.
UK and Australian ring sizes use an alphabetical system (A–Z+) where each letter corresponds to a finger circumference increment of about 1.25 mm. The system is also used in Ireland, New Zealand, and South Africa.
UK letter sizing is intuitive for half sizes — 'F½' is between F and G. The most common UK women's sizes are L–P; men's P–T. UK size N ≈ US size 7 ≈ EU 54 — the most common global reference size.
Interesting fact: The UK ring sizing system is also used in Australia and Ireland despite metrication — a legacy of the British Imperial measurement tradition that persists in the jewellery trade even though lengths are now measured in mm.
US and Canadian ring sizes use a numerical scale (0–13+) where each half size corresponds to a finger circumference increment of about 1.3 mm. The system has no standardized international anchor — US size 7 ≈ 54.4 mm circumference, widely used as a reference for a 'medium' adult ring.
US ring sizing is the most common reference in online jewellery sales globally. Most international jewellers list US sizes alongside their local system. The average US women's ring size is 6–7; men's 9–10.
Interesting fact: Ring sizing developed from mandrel-based measurement — jewellers used tapered metal cones marked with arbitrary numbers. Different countries independently chose different numbering anchors, creating the incompatible systems that persist today.
Ring sizes are not internationally standardized. US/Canada use a numerical scale (0–13); UK/Australia use letters (A–Z+); EU/Germany use circumference in mm (the most physically direct system). The universal anchor: US 7 = UK N = EU 54 = 54.4 mm circumference = 17.3 mm diameter.
For the most accurate measurement, wrap a strip of paper around the base of your finger, mark the overlap, and measure in mm — that IS your EU size. Always measure at the end of the day.