International Ring Size Conversion Chart: Australia, UK and US Ring Sizes
Whether you've measured the diameter of an existing ring, you know your size in one system and need to convert it to another, or you're simply trying to make sense of the different ring sizing systems used around the world — this guide and our free downloadable ring size conversion chart will give you everything you need.
Our chart covers the two sizing systems we use at Rebecca Cordingley Jewellery: the Australian and UK alphabetical system, and the US and Canadian numerical system. It also includes inside diameter and inside circumference measurements in both millimetres and inches, so you can find your size from a physical measurement if needed.
Download our free international ring size conversion chart
Ring Size Systems Explained
Ring sizes are not universal. Different countries use different sizing systems, which can cause significant confusion when shopping for rings online — particularly from international jewellers or when converting a size you already know into an unfamiliar system.
The Australian and UK Ring Size System
Australia, the United Kingdom, Ireland, South Africa and New Zealand all use the same alphabetical ring sizing system. Sizes run from A to Z+6, with each full letter representing a step up in size. Half sizes are also available in this system, expressed as a letter followed by ½ — for example, N½.
This is the primary sizing system used in Australia and the one most Australian jewellers, including ourselves, work with as standard.
The US and Canadian Ring Size System
The United States, Canada and Mexico use a numerical ring sizing system, with sizes typically ranging from 1 to 16, including half sizes. This system is widely used in North American jewellery retail and online shopping platforms, and is the system most commonly encountered when shopping from US-based jewellers or marketplaces.
At Rebecca Cordingley Jewellery, we accept ring orders in both the Australian/UK alphabetical system and the US/Canadian numerical system. If you know your size in either system, simply place your order using whichever size you have.
How to Use Our Ring Size Conversion Chart
Our ring size conversion chart includes the following columns:
- Inside diameter in millimetres (mm) — the measurement straight across the inside of the ring at its widest point, in millimetres
- Inside diameter in inches — the same measurement expressed in inches
- Inside circumference in millimetres (mm) — the measurement around the inside of the ring, in millimetres
- Inside circumference in inches — the same measurement expressed in inches
- Australian / UK / Irish / South African / New Zealand ring size — the corresponding alphabetical size
- US / Canadian / Mexican ring size — the corresponding numerical size
Converting from a Physical Measurement
If you have measured the internal diameter or internal circumference of an existing ring
using digital callipers or a ruler, find your measurement in the relevant column of the chart and read across to find your corresponding Australian/UK or US ring size.
If your measurement falls between two sizes on the chart, we recommend choosing the larger size rather than the smaller one. Fingers change size slightly throughout the day and in different temperatures, and a ring that is marginally too tight is significantly more uncomfortable — and more difficult to remove — than one with a little extra room.
Converting Between the Australian/UK and US Systems
If you already know your ring size in one system and need to convert it to the other, simply find your size in the relevant column and read across to the other system. For example, an Australian/UK size N is equivalent to a US size 6¾. A US size 7 is equivalent to an Australian/UK size N 1/2.
Download our free ring size conversion chart to keep a copy for reference.
Tips for Getting Your Ring Size Right
Always size up when in doubt
If your measurement falls between two sizes, choose the larger. A slightly larger ring is comfortable and wearable; one that is too small can be painful to wear and difficult to remove.
Your fingers change size throughout the day
Fingers tend to be slightly larger in the afternoon and evening, and smaller in the morning or when cold. For the most representative measurement, size your finger in the afternoon at a comfortable room temperature.
Your dominant hand is larger
Your dominant hand — the one you write with — is typically slightly larger than your non-dominant hand due to greater muscle use. Always measure the specific finger on the specific hand you intend to wear the ring on.
Wide band rings need a larger size
If the ring you are purchasing has a band wider than approximately 4mm for women or 6mm for men, you will need to order a larger size than your standard ring size. Wide bands sit differently on the finger and require more room to fit comfortably. Our product pages will indicate when a wide band size adjustment is required.
For a full guide to ring sizing methods — including how to measure at home, how to use a ring sizer, and how to measure an existing ring — read our detailed guide on how to find your ring size. This guide explains how to find your wide band ring size.
How We Size Our Rings
All rings at Rebecca Cordingley Jewellery are made to order in your specified size in our South Australian studio. We accept sizes in both the Australian/UK alphabetical system and the US/Canadian numerical system — simply enter your size when placing your order. If you are ordering in the US/Canadian numerical system, select ‘Other - will advise’ and leave use a note with your size during checkout.
Because our rings are made to order, getting your size right before ordering is important. If you are at all unsure, we recommend:
- Having your ring size measured professionally at a local jewellery store — most will do this free of charge
- Purchasing one of our affordable ring sizers for an at-home measurement
- Contacting us before ordering if you have any questions about sizing
Browse our full collection of sterling silver rings — including fidget rings, stacking rings, statement rings and wedding bands — all handmade to order in solid sterling silver and shipped across Australia and worldwide.
Frequently Asked Questions
How do I convert an Australian ring size to a US ring size?
Find your Australian/UK size in the relevant column of our ring size conversion chart and read across to the US/Canadian column to find the equivalent size. For example, an Australian/UK size N is equivalent to a US size 6¾, and an Australian/UK size P is equivalent to a US size 7¾. Download our free chart for the complete size-by-size conversion.
How do I convert a US ring size to an Australian ring size?
Find your US/Canadian size in the numerical column of our ring size conversion chart and read across to the Australian/UK column. For example, a US size 7 is equivalent to an Australian/UK size N 1/2, and a US size 9 is equivalent to an Australian/UK size R 1/2. Our downloadable chart covers all sizes including half sizes.
How do I find my ring size from a measurement in millimetres?
If you have measured the internal diameter of an existing ring in millimetres, find your measurement in the inside diameter column of our ring size conversion chart and read across to find your Australian/UK or US ring size. If your measurement falls between two sizes, choose the larger size for comfort.
What ring size systems do you use at Rebecca Cordingley Jewellery?
We accept ring orders in both the Australian/UK alphabetical system and the US/Canadian numerical system. Simply select your preferred system and enter your size when placing your order. If you are unsure which system applies to you or need help converting your size, our ring size conversion chart covers both systems in full.
What if my ring size falls between two sizes on the chart?
If your measurement falls between two sizes, we recommend choosing the larger size. Fingers fluctuate slightly in size throughout the day and in different temperatures, and a ring that is marginally too large is far more comfortable than one that is too tight. If you are unsure, contact us before ordering and we will be happy to advise.
Do you offer wide band ring sizing?
Yes. Wide band rings require a larger size than standard rings because the wider band sits differently on the finger. As a general guide, wide band rings are approximately half a size larger in the US system and a full size larger in the Australian/UK system, though this varies between individuals. Our product pages indicate when a wide band size is required, and we recommend professional measurement for wide band styles where possible.