Everything you need to find the perfect engagement ring size — average AU women's sizes, full conversion chart, secret sizing methods, how to measure at home, and a free calculator
The full women's engagement ring range spans AU F (very small/petite) to AU U+ (larger sizes). The majority of Australian women fall between AU J and AU P. Colour-coded scale below:
| 💍 AU / UK / NZ | 🇺🇸 US / CA | 🇪🇺 EU (mm) | 🇮🇳 India | Diameter (mm) | Circumference (mm) | Typical Wearer |
|---|---|---|---|---|---|---|
| F | 3 | 44.2 | 4 | 14.1 mm | 44.2 mm | 🔹 Very Petite |
| G | 3½ | 45.5 | 5 | 14.5 mm | 45.5 mm | 🔹 Very Petite |
| H | 4 | 46.8 | 7 | 14.9 mm | 46.8 mm | 🔹 Petite |
| H½ | 4¼ | 47.4 | — | 15.1 mm | 47.4 mm | 🔹 Petite |
| I | 4½ | 48.0 | 8 | 15.3 mm | 48.0 mm | 💕 Small |
| I½ | 4¾ | 48.7 | — | 15.5 mm | 48.7 mm | 💕 Small |
| J | 5 | 49.3 | 9 | 15.7 mm | 49.3 mm | 💕 Below Avg |
| J½ | 5¼ | 50.0 | — | 15.9 mm | 50.0 mm | 💕 Below Avg |
| K | 5½ | 50.6 | 10 | 16.1 mm | 50.6 mm | 💕 Common |
| K½ | 5¾ | 51.2 | — | 16.3 mm | 51.2 mm | 💕 Common |
| L | 6 | 51.9 | 12 | 16.5 mm | 51.9 mm | 💕 Very Common |
| L½ | 6¼ | 52.5 | — | 16.7 mm | 52.5 mm | 💕 Very Common |
| M ⭐ | 6½ | 53.1 | 13 | 16.9 mm | 53.1 mm | ⭐ Most Common |
| M½ ⭐ | 6¾ | 53.8 | — | 17.1 mm | 53.8 mm | ⭐ Most Common |
| N ⭐ | 7 | 54.4 | 14 | 17.3 mm | 54.4 mm | ⭐ Most Common |
| N½ | 7¼ | 55.1 | — | 17.5 mm | 55.1 mm | 💕 Very Common |
| O | 7½ | 55.7 | 15 | 17.7 mm | 55.7 mm | 💕 Common |
| O½ | 7¾ | 56.3 | — | 17.9 mm | 56.3 mm | 💕 Common |
| P | 8 | 57.0 | 16 | 18.1 mm | 57.0 mm | 🔶 Above Avg |
| P½ | 8¼ | 57.6 | — | 18.3 mm | 57.6 mm | 🔶 Above Avg |
| Q | 8½ | 58.3 | 17 | 18.5 mm | 58.3 mm | 🔶 Large |
| R | 8¾ | 58.9 | 18 | 18.8 mm | 58.9 mm | 🔶 Large |
| S | 9¼ | 60.2 | 19 | 19.2 mm | 60.2 mm | 🔷 XL |
| T | 9¾ | 61.4 | 21 | 19.6 mm | 61.4 mm | 🔷 XL |
The most accurate secret method. Borrow a ring she wears on her ring finger (left hand, fourth finger). Take it to any jeweller — they'll measure it in seconds at no cost. Return it the same day. Make sure it's from the correct finger and hand, not a thumb or right-hand ring.
Press one of her rings firmly into a bar of soap or modelling clay to create an impression of the inner circle. Take the impression to a jeweller for measurement. This works especially well with a well-defined gold or platinum ring that leaves a clear edge impression.
Slide a thin strip of paper inside one of her rings and mark where the paper meets. Measure that length — it gives you the inner circumference in mm. Match it to the chart above. Even a 1 mm reading error is only half an AU letter size, easy to adjust at a jeweller.
A trusted friend or family member may already know her ring size, or can help arrange a covert measurement. Friends can also casually try rings on "for fun" at a jeweller while your partner is present, noting what size fits comfortably.
Gently press a ring sizer or paper strip around her ring finger while she sleeps. This is notoriously unreliable as sleeping fingers are smallest and most relaxed — they'll typically read 1–2 mm smaller than her actual everyday size. Add ½ AU size to any sleeping measurement.
Order in AU N (US 7) — the most common women's ring size. If it doesn't fit perfectly, get it resized after the proposal for $30–$80 at any jeweller. Most gold, silver, and platinum rings can be resized 1–2 sizes up or down easily. This is the standard jewellery industry advice for surprise proposals.
Standard printer paper works best. Avoid tissue, kitchen paper, or any stretchy material — these compress and give readings that are too small by 1–3 mm. For women's engagement ring sizing, accuracy of 0.5 mm matters because one full AU size is only 1.25 mm in circumference.
In Australia, engagement rings are traditionally worn on the left ring finger. The strip should feel like a snug, comfortable ring — not tight. You should be able to slide it very slightly. If it won't slide at all, it's too tight and will give a reading that's too large.
Never remove the strip before marking. A fine ballpoint pen gives the sharpest mark. A thick felt-tip can add 1–2 mm of error. The pen mark must be a fine vertical line, not a smear across the paper.
Lay the strip flat on a hard surface with a ruler. Your reading in mm is your finger circumference. For AU M your reading will be approximately 53 mm; for AU N approximately 54.4 mm. Even a 0.6 mm error moves you half an AU size.
Finger size changes throughout the day — smallest in the morning, largest in the afternoon. Measure at mid-afternoon for the most representative result. Average three readings taken at different times. Always round up to the larger AU letter when between two sizes.
Petite women (under 160 cm) typically wear AU H–K. Average height women wear AU L–N. Taller women (above 172 cm) often wear AU N–Q. This is a rough guide only — slender tall women may still wear AU K.
Hot Australian summers cause finger swelling — often ½ to 1 full AU size. A woman who wears AU M in winter may need AU M½ or N in a Queensland summer. Measure in conditions similar to when the ring will be worn daily.
The dominant (writing) hand is typically ½ to 1 AU size larger than the non-dominant hand due to muscle use. Engagement rings are worn on the left hand — always measure the left ring finger specifically, not the right hand.
Ring size naturally increases slightly with age. Many women find they wear ½–1 AU size larger in their 40s compared to their 20s. For a long-term engagement or heirloom ring, sizing can be confirmed again before ordering the final piece.
Pregnancy, hormonal contraceptives, thyroid conditions, and certain medications can cause significant finger size changes. If any of these apply, measure at a stable period and note any expected changes when choosing a style that can be resized.
Fingers are 0.5–1.5 mm smaller in circumference first thing in the morning compared to late afternoon. For most women this is ½ AU size difference. Always measure at the same time of day for consistent readings — mid-afternoon is the industry standard.
Enter your finger circumference (paper strip mm), inner diameter of an existing ring, or your US ring size — get your AU letter size instantly