Ring Size Chart
Find a ring size at home with a chart, a printable sizer and an on-screen sizer. The chart lists US and Canada sizes from 3 to 13 in half sizes with the inner diameter and inner circumference in millimetres, and the matching UK, Ireland and Australia letter, EU (ISO 8653) size and Japanese size, each worked out from its published rule. Print the sizer strips (one per size system) or the circle chart on US Letter or A4: every page has a card outline and a ruler, so you can check that it printed at exactly 100% before you measure. Already have a measurement? Type the circumference or diameter in millimetres and see the nearest size in every system, or lay a ring on the on-screen circle after matching a bank card to the screen. A paper sizer is a good guide, but fingers change through the day, so measure more than once and confirm with a jeweller before you buy or resize a ring. Nothing is uploaded.
100% private — everything runs in your browser. Everything runs in your browser; nothing is uploaded.
Print at 100% (Actual size), then check that a bank or ID card covers the card outline exactly before you cut.
Size from a measurement
On-screen sizer
1. Hold a bank or ID card upright against the screen and drag the slider until the outline is exactly as wide as the card’s short side.
2. Lay a ring that fits on the circle and step the size until the circle fills the inside of the ring.
Paper
Sizes
Strips (one per size system)
Colour
Runs in your browser with our own code: nothing is uploaded and nothing is saved. A printed or on-screen sizer is a guide only: measure more than once and confirm the size with a jeweller before you buy or resize a ring. The designs are our own drawings: you may use them and anything you make with them, including things you sell, with no credit needed.
How to find your ring size at home
- Choose US Letter or A4 and download the PDF.
- Print at 100% (Actual size) and check that a bank or ID card covers the card outline exactly; if not, print again without scaling.
- Cut out a strip and its slit, wrap it around the base of the finger with the numbers outside, and thread the narrow end through the slit.
- Pull it snug, check it slides over the knuckle, and read the size at the slit. Or lay a ring that fits on the circle chart and pick the circle that fills its inside.
- Between two sizes, choose the larger, then confirm with a jeweller before you buy.
What you can use it for
- Find a ring size before buying a ring online
- Check the size of a ring you already own
- Convert a US size to UK, EU or Japanese sizes
- Size a surprise engagement ring from a ring the person already wears
- Make a quick sizer for a craft or a class
- Print a chart to keep with a jewellery collection
Ring size chart (US, UK, EU and Japan)
| US and Canada | Inner diameter (mm) | Inner circumference (mm) | UK, Ireland and Australia | EU (ISO 8653) | Japan |
|---|---|---|---|---|---|
| 3 | 14.07 | 44.2 | F½ | 44 | 4 |
| 3½ | 14.47 | 45.5 | G½ | 45 | 5 |
| 4 | 14.88 | 46.8 | H½ | 47 | 7 |
| 4½ | 15.29 | 48.0 | I½ | 48 | 8 |
| 5 | 15.69 | 49.3 | J½ | 49 | 9 |
| 5½ | 16.10 | 50.6 | K½ | 51 | 10 |
| 6 | 16.51 | 51.9 | L½ | 52 | 12 |
| 6½ | 16.91 | 53.1 | M½ | 53 | 13 |
| 7 | 17.32 | 54.4 | N½ | 54 | 14 |
| 7½ | 17.73 | 55.7 | O½ | 56 | 15 |
| 8 | 18.13 | 57.0 | P½ | 57 | 16 |
| 8½ | 18.54 | 58.2 | Q½ | 58 | 18 |
| 9 | 18.95 | 59.5 | R½ | 60 | 19 |
| 9½ | 19.35 | 60.8 | S½ | 61 | 20 |
| 10 | 19.76 | 62.1 | T½ | 62 | 21 |
| 10½ | 20.16 | 63.3 | U½ | 63 | 22 |
| 11 | 20.57 | 64.6 | V½ | 65 | 24 |
| 11½ | 20.98 | 65.9 | W½ | 66 | 25 |
| 12 | 21.38 | 67.2 | X½ | 67 | 26 |
| 12½ | 21.79 | 68.5 | Z | 68 | 27 |
| 13 | 22.20 | 69.7 | Z+1 | 70 | 29 |
Diameters follow the US rule (0.8128 mm per whole size from 11.63 mm at size 0) and circumferences are π × diameter. The UK, EU and Japanese columns are the nearest size in each system to that circumference.
Quarter sizes
| US size | Inner diameter (mm) | Inner circumference (mm) |
|---|---|---|
| 5¼ | 15.90 | 49.9 |
| 5¾ | 16.30 | 51.2 |
| 6¼ | 16.71 | 52.5 |
| 6¾ | 17.12 | 53.8 |
| 7¼ | 17.52 | 55.0 |
| 7¾ | 17.93 | 56.3 |
US sizes also come in quarter steps. The circle chart prints them if you choose Quarter sizes; the strips show quarter ticks between the half sizes.
EU sizes in millimetres
| EU size (circumference, mm) | Inner diameter (mm) | Nearest US | Nearest UK | Nearest Japan |
|---|---|---|---|---|
| 44 | 14.01 | 3 | F | 4 |
| 46 | 14.64 | 3¾ | H | 6 |
| 48 | 15.28 | 4½ | I½ | 8 |
| 50 | 15.92 | 5¼ | K | 10 |
| 52 | 16.55 | 6 | L½ | 12 |
| 54 | 17.19 | 6¾ | N | 14 |
| 56 | 17.83 | 7½ | P | 15 |
| 58 | 18.46 | 8½ | Q½ | 17 |
| 60 | 19.10 | 9¼ | S | 19 |
| 62 | 19.74 | 10 | T½ | 21 |
| 64 | 20.37 | 10¾ | V | 23 |
| 66 | 21.01 | 11½ | X | 25 |
| 68 | 21.65 | 12¼ | Y½ | 27 |
| 70 | 22.28 | 13 | Z+1 | 29 |
An EU (ISO 8653) size is simply the inner circumference in millimetres, so a measurement of 54 mm around the finger is EU 54.
Where the sizes come from
| System | Rule used here | Source |
|---|---|---|
| US and Canada | Inner diameter = 0.8128 × size + 11.63 mm; whole sizes 0.032 in apart | Ring size article (Wikipedia), which quotes the North American scale |
| UK, Ireland and Australia | 1.25 mm of circumference per letter, size C = 40 mm, half sizes between | British Standard 6820:1987, as cited in the same article |
| EU | Size = inner circumference in mm | ISO 8653:2016 |
| Japan | Inner diameter = 13.0 + (size − 1) ÷ 3 mm | Japanese ring size table (JCS rule) from a Japanese jeweller |
| Print check | Card outline 85.60 × 53.98 mm | ISO/IEC 7810 ID-1 card size (bank and ID cards) |
Jewellers’ own charts round these numbers in slightly different ways, so two charts can disagree by a fraction of a size.
What prints
| Page | What is on it |
|---|---|
| Sizer strips | A card outline, a 15 cm ruler and a 5 in ruler, then one strip each for US, UK, EU and Japanese sizes (untick any you do not need) |
| Circle chart | A card-width line and rulers, then circles at the inner diameter of every US size in your range, each labelled with its UK, EU and Japanese size |
| Both | The strips page and the circle chart in one PDF |
Tips for an accurate size
- Measure at the end of the day, when fingers are a little larger, and not when your hands are cold.
- Measure the finger the ring is for: hands can differ by a size.
- Check that the strip slides over the knuckle as well as sitting snug at the base.
- Wide bands fit tighter than narrow ones, so allow a little more room.
- Measure two or three times and use the size you get most often.
More measuring tools
Measure on screen with the Online Ruler, look up hand measurements on the Hand Size Chart, or convert a measurement with MM to Inches and CM to Inches.
More free tools
Measuring something small?
Sizing charts and measuring tools that run privately in your browser, with no sign-up.
Frequently asked questions
How do I find my ring size at home?
Print the sizer at 100% and check the card outline, then wrap a strip around the base of your finger and read the size at the slit. Or measure a ring that already fits: lay it on the circle chart, or measure across its inside in millimetres and type that into the converter. Measure more than once and confirm with a jeweller before you buy.
How do I make sure the printable ring sizer is the right size?
Print with scaling off (100% or Actual size). Each page has an outline of a bank or ID card, 85.60 × 53.98 mm, and a ruler in centimetres and inches. If a card does not cover the outline exactly, or 10 cm on the ruler is not 10 cm, the printer scaled the page: print it again.
What is my ring size in mm?
Ring sizes are set by the inside of the ring. A US size 7, for example, has an inner diameter of about 17.32 mm and an inner circumference of about 54.4 mm. The chart gives both numbers for every US size from 3 to 13.
How do US, UK, EU and Japanese ring sizes compare?
US sizes go up by 0.8128 mm of inner diameter per whole size, UK sizes by 1.25 mm of circumference per letter, EU sizes are the inner circumference in mm (ISO 8653) and Japanese sizes go up by one third of a millimetre of diameter per size. Because the steps differ, a conversion is the nearest size, not an exact match.
Should I size up or down if I am between sizes?
Choose the larger size. A ring that is slightly loose is more comfortable than one that will not pass the knuckle, and wide bands usually need a little more room than narrow ones.
Can I use string to measure my ring size?
Yes. Wrap a thin strip of paper or string around the base of the finger, mark where it overlaps, lay it flat and measure the length in millimetres. Type it into the converter as a circumference. String can stretch and pull tight, so a paper strip is usually steadier.
Does the on-screen sizer work on a phone?
Yes, after you match the card outline to a real bank or ID card held against the screen. Screens differ in pixel density, so the calibration step matters; skip it and the circle may be the wrong size.
Can a printable sizer replace a jeweller?
No. Paper has thickness, fingers swell with heat and shrink with cold, and a knuckle can be wider than the base of the finger. Use the sizer as a starting point and confirm with a jeweller’s ring gauge before you buy or resize a ring.
Which UK letter matches a US size?
Each UK letter is 1.25 mm of circumference, and each half US size is about 1.28 mm, so the UK letter beside a US size is the nearest half letter. Jewellers’ charts can differ by about half a size, which is another reason to confirm in person.
Is anything uploaded?
No. Everything is drawn by JavaScript in your browser and never leaves your device, and nothing is saved when you close the page.