Convert Australian letter sizes to Canadian numeric ring sizes using the physical measurements that matter: inner diameter and circumference in millimetres. Includes an interactive calculator, full AU-to-Canada chart, printable reference and detailed buying guide for 2026.
| ๐ฆ๐บ Australian Size | Inner Diameter | Circumference | ๐จ๐ฆ Canada Size | Canada Chart Diameter | Match |
|---|---|---|---|---|---|
| F | 14.00 mm | 44.0 mm | 3 | 14.00 mm | Direct match |
| Fยฝ | 14.20 mm | 44.6 mm | 3 | 14.00 mm | Nearest size |
| G | 14.40 mm | 45.2 mm | 3.5 | 14.40 mm | Direct match |
| Gยฝ | 14.70 mm | 46.2 mm | 4 | 14.80 mm | Very close |
| H | 14.80 mm | 46.5 mm | 4 | 14.80 mm | Direct match |
| Hยฝ | 15.00 mm | 47.1 mm | 4 | 14.80 mm | Nearest size |
| I | 15.26 mm | 47.9 mm | 4.5 | 15.20 mm | Very close |
| Iยฝ | 15.35 mm | 48.2 mm | 4.5 | 15.20 mm | Very close |
| J | 15.62 mm | 49.1 mm | 5 | 15.60 mm | Direct match |
| Jยฝ | 15.90 mm | 50.0 mm | 5.5 | 16.00 mm | Very close |
| K | 16.00 mm | 50.3 mm | 5.5 | 16.00 mm | Direct match |
| Kยฝ | 16.30 mm | 51.2 mm | 6 | 16.45 mm | Very close |
| L | 16.44 mm | 51.6 mm | 6 | 16.45 mm | Direct match |
| Lยฝ | 16.60 mm | 52.2 mm | 6 | 16.45 mm | Very close |
| M | 16.80 mm | 52.8 mm | 6.5 | 16.90 mm | Very close |
| Mยฝ | 17.00 mm | 53.4 mm | 6.5 | 16.90 mm | Very close |
| N | 17.18 mm | 54.0 mm | 7 | 17.30 mm | Very close |
| Nยฝ | 17.40 mm | 54.7 mm | 7 | 17.30 mm | Very close |
| O | 17.55 mm | 55.1 mm | 7.5 | 17.70 mm | Very close |
| Oยฝ | 17.80 mm | 55.9 mm | 7.5 | 17.70 mm | Very close |
| P | 18.00 mm | 56.5 mm | 8 | 18.20 mm | Nearest size |
| Pยฝ | 18.20 mm | 57.2 mm | 8 | 18.20 mm | Direct match |
| Q | 18.30 mm | 57.5 mm | 8 | 18.20 mm | Very close |
| Qยฝ | 18.60 mm | 58.4 mm | 8.5 | 18.60 mm | Direct match |
| R | 18.80 mm | 59.1 mm | 8.5 | 18.60 mm | Nearest size |
| Rยฝ | 19.00 mm | 59.7 mm | 9 | 19.00 mm | Direct match |
| S | 19.20 mm | 60.3 mm | 9 | 19.00 mm | Nearest size |
| Sยฝ | 19.40 mm | 60.9 mm | 9.5 | 19.40 mm | Direct match |
| T | 19.60 mm | 61.6 mm | 10 | 19.80 mm | Nearest size |
| Tยฝ | 19.80 mm | 62.2 mm | 10 | 19.80 mm | Direct match |
| U | 20.10 mm | 63.1 mm | 10.5 | 20.20 mm | Very close |
| Uยฝ | 20.20 mm | 63.5 mm | 10.5 | 20.20 mm | Direct match |
| V | 20.40 mm | 64.1 mm | 10.5 | 20.20 mm | Nearest size |
| Vยฝ | 20.60 mm | 64.7 mm | 11 | 20.60 mm | Direct match |
| W | 20.80 mm | 65.3 mm | 11 | 20.60 mm | Nearest size |
| Wยฝ | 21.00 mm | 66.0 mm | 11.5 | 21.00 mm | Direct match |
| X | 21.10 mm | 66.3 mm | 11.5 | 21.00 mm | Very close |
| Xยฝ | 21.40 mm | 67.2 mm | 12 | 21.40 mm | Direct match |
| Y | 21.50 mm | 67.5 mm | 12 | 21.40 mm | Very close |
| Yยฝ | 21.70 mm | 68.2 mm | 12.5 | 21.80 mm | Very close |
| Z | 21.90 mm | 68.8 mm | 12.5 | 21.80 mm | Very close |
| Zยฝ | 22.10 mm | 69.4 mm | 13 | 22.20 mm | Very close |
Australian diameters in this chart follow the Michael Hill Australia printable letter guide. Canadian numeric references follow the standard US-size and internal-diameter chart published by Peoples Jewellers Canada. Named sizes remain approximate because manufacturers can apply small tolerances.
Australian jewellery sellers commonly identify ring sizes with letters such as J, M, N, Q and T, including half-letter options such as Nยฝ or Qยฝ. The system is closely aligned with the letter format also used in the United Kingdom and New Zealand. A letter is only a label: the true physical fit comes from the ring's internal diameter and circumference.
Australian charts can include small steps between adjacent letters. For example, the source chart used here lists N at approximately 17.18 mm diameter and Nยฝ at approximately 17.4 mm. That level of detail is useful, but it means two nearby Australian letters may convert to the same Canadian half-number.
Canadian jewellery websites commonly present North American numeric sizes such as 5, 6.5, 7, 8 and 10. These are generally the same numbers shoppers see on US jewellery sites, although a seller may round the associated millimetre measurements differently. Peoples Jewellers, for example, publishes a chart headed โStandard (US) Sizeโ for Canadian customers.
When buying from Canada with an Australian size, do not convert by alphabet position. Match the Australian diameter to the nearest numeric row on the Canadian seller's current chart. This is particularly important for half letters, wide bands and products offered only in whole-number sizes.
Examples: J, Mยฝ, N, Qยฝ and T.
Use internal diameter or finger circumference.
Examples: 5, 6.5, 7, 8.5 and 10.
Check whether the size is a whole letter or a half letter. AU N and AU Nยฝ are different physical measurements, even though both may be offered as the same nearest Canadian number by a retailer with wider size intervals.
Use a published chart from the original Australian seller whenever available. If you own the ring, measure its internal opening directly. Avoid relying on a generic chart when the seller provides product-specific measurements.
Compare the AU diameter with the Canadian seller's chart and select the closest row. For example, AU N at about 17.18 mm is closer to Canadian size 7 at about 17.3 mm than to size 6.5 at about 16.9 mm.
A broad, flat interior may feel tighter than a narrow or rounded comfort-fit band at the same measured opening. Use the conversion as a starting point, then follow the seller's guidance for band width and profile.
Ask the Canadian seller to confirm the chosen size against your diameter and circumference before engraving, made-to-order production or final-sale purchase. A millimetre measurement is clearer than sending only an Australian letter.
Print at 100% with โfit to pageโ disabled. First confirm that the calibration bar measures exactly 50 mm. The circles below are selected reference sizes; use the full chart for intermediate results.
An Australian letter sequence and a Canadian numeric sequence do not divide the diameter range in exactly the same way. The Australian source chart includes whole and half letters with steps that may be roughly 0.1 to 0.3 mm. The Canadian source chart advances in half-number steps that are often around 0.4 mm apart. As a result, more than one Australian size can be closest to the same Canadian number.
For example, AU N and AU Nยฝ are both close to Canada 7, while AU P, Pยฝ and Q all sit near Canada 8. This does not mean those Australian sizes are identical. It means the Canadian reference chart has a broader interval around that number. A Canadian seller offering quarter sizes, custom sizes or a different tolerance may recommend another result.
The best practice is to send both measurements: โMy ring has a 17.4 mm inside diameter and approximately 54.7 mm circumference.โ That information allows the jeweller to account for the exact product, band profile and manufacturing system instead of depending only on the phrase โAU Nยฝ.โ
17.3 mm ร 3.1416 โ 54.35 mm.
54.35 mm รท 3.1416 โ 17.3 mm.
Compare the two chart openings, not the labels.
A broad wedding band covers more skin than a narrow solitaire band.
A domed inside profile can slide differently from a flat interior.
Heat, cold and activity can temporarily change finger circumference.
The ring must pass the knuckle but remain secure at the base.
Stones around the full band can restrict later size changes.
Tungsten, titanium and patterned bands may not resize normally.
Explains Australia's letter system, measuring an existing ring and measuring finger circumference in millimetres.
View Australian sizing guidance โDescribes a Canadian-friendly number system and the same diameter and circumference measuring methods.
View Canadian sizing guidance โPublishes standard North American numeric sizes with internal diameters and European equivalents.
View Canadian comparison chart โInternational standard covering ring-size definition, measurement and designation using professional gauges.
View the ISO standard overview โ