Ring Size Conversion Tool
Find your perfect ring size across different international systems. This calculator converts between US, UK, EU, and other regional sizing standards. Simply enter your finger measurements or an existing ring's diameter, and discover equivalent sizes for shopping anywhere in the world.
Tips for Finding Your Perfect Ring Size:
- Measure your finger at the end of the day when your fingers are typically at their largest
- Measure 3-4 times to ensure accuracy
- Consider the width of the band - wider bands fit more snugly
- If you're between sizes, opt for the larger size
- Account for temperature - fingers expand in warm weather and shrink in cold
- Remember that your dominant hand is usually slightly larger
- For knuckles significantly larger than the base of your finger, measure both and choose a size in between
International Ring Size Conversion Chart
| Diameter (mm) | Circumference (mm) | US / Canada | UK / Australia | EU / France | Germany | Japan | Switzerland |
|---|---|---|---|---|---|---|---|
| 14.9 | 46.8 | 4 | H | 47½ | 15 | 8 | 8 |
| 15.3 | 48.0 | 4½ | I | 48¾ | 15½ | 9 | 8¾ |
| 15.7 | 49.3 | 5 | J½ | 50 | 16 | 10 | 9½ |
| 16.1 | 50.6 | 5½ | K½ | 51¼ | 16½ | 11 | 10¼ |
| 16.5 | 51.8 | 6 | L½ | 52½ | 17 | 12 | 11 |
| 16.9 | 53.1 | 6½ | M½ | 53¾ | 17¼ | 13 | 11¾ |
| 17.3 | 54.4 | 7 | O | 55 | 17¾ | 14 | 12½ |
| 17.7 | 55.7 | 7½ | P | 56¼ | 18 | 15 | 13¼ |
| 18.1 | 57.0 | 8 | Q | 57½ | 18½ | 16 | 14 |
| 18.5 | 58.3 | 8½ | R | 58¾ | 19 | 17 | 14¾ |
How to Measure Your Ring Size
Method 1: String or Paper Strip
- Cut a strip of paper about 4 inches long and ¼ inch wide.
- Wrap it around the base of your finger where the ring will sit.
- Mark where the paper overlaps forming a complete circle.
- Measure the length from the start to the mark in millimeters.
- Use this circumference measurement in the calculator.
Method 2: Measuring an Existing Ring
- Find a ring that fits well on the desired finger.
- Place the ring on a ruler or measuring tape.
- Measure the inside diameter from one inner edge to the opposite inner edge in millimeters.
- Use this diameter measurement in the calculator.
Understanding Ring Sizes Worldwide
Ring sizing can be confusing, especially when shopping internationally. Different countries use different measurement systems, and understanding how they relate to each other will help you find the perfect fit no matter where you're shopping.
Common Ring Sizing Systems
US and Canada Sizing
The American and Canadian sizing system uses numbers (typically from 3 to 13 for adults) with quarter-size increments (e.g., 6, 6¼, 6½, 6¾). Each full size represents a 0.8mm increase in inside diameter. This system is the most common in North America and is often referenced by international jewelry retailers.
UK and Australia Sizing
The British and Australian sizing system uses letters from A to Z+ with half sizes indicated (e.g., J, J½, K). This alphabetical scale increases in irregular increments, which can make precise conversions challenging. A UK size M is approximately equivalent to a US size 6.
European Sizing
European countries typically use a numerical scale that measures the inside circumference of the ring in millimeters. These sizes generally range from 41 to 76. Some European countries like France may slightly adjust this scale, but the differences are minimal. A European size 52 is approximately equivalent to a US size 6.
Japanese Sizing
Japan uses a numerical scale based on the inside diameter of the ring measured in millimeters, multiplied by 3. So a ring with an inner diameter of 16mm would be a size 16. Japanese sizes typically range from 5 to 27 for adults. A Japanese size 13 is approximately equivalent to a US size 6½.
Factors Affecting Ring Fit
Finding the right ring size involves more than just measuring your finger. Several factors can affect how a ring fits and feels:
Temperature
Fingers naturally expand in warm weather and contract in cold weather. This can cause a difference of up to half a size between summer and winter. For this reason, it's best to measure your finger at a normal room temperature.
Time of Day
Your fingers are typically smaller in the morning and may swell throughout the day, especially if you consume salt, alcohol, or during physical activity. For the most accurate measurement, size your finger in the evening when it's likely at its largest.
Band Width
Wider bands tend to fit more snugly than narrow bands. If you're choosing a wide band (more than 6mm), you might need to go up half a size from your usual measurement. Conversely, very thin bands may feel looser.
Knuckle Size
If your knuckle is significantly larger than the base of your finger, you'll need to find a balance. The ring needs to be large enough to slide over your knuckle but not so large that it spins around once in place. Consider rings with special designs or comfort-fit styles for this situation.
How to Ensure the Perfect Fit
Finding the perfect ring size is especially important for rings meant to be worn daily, such as wedding and engagement rings. Here are some tips to ensure the best fit:
Multiple Measurements
Measure your finger 3-4 times on different days and at different times of day. Take an average of these measurements for the most accurate size.
Professional Sizing
For important rings, visit a jeweler for professional sizing. They have ring sizers that can accurately determine your size and can offer advice based on the specific ring design you're interested in.
Comfort Fit vs. Standard Fit
Comfort-fit rings have a slightly rounded interior surface, which can make them feel looser than standard-fit rings of the same size. If you're switching between these styles, you might need to adjust your size accordingly.
Seasonal Considerations
If you're purchasing a ring to be worn year-round, consider when you'll be receiving and first wearing it. If sized in winter, it might be too tight in summer, and vice versa.
Regional Variations in Ring Design
Beyond sizing differences, ring designs and traditions vary around the world:
North America
In the United States and Canada, engagement rings typically feature a prominent diamond or gemstone in a solitaire or halo setting. Wedding bands are often simpler and complement the engagement ring.
Europe
European designs often emphasize craftsmanship and may incorporate more intricate metalwork. In many Northern European countries, wedding rings are worn on the right hand rather than the left.
Asia
In countries like China and Japan, traditional rings may incorporate jade, which symbolizes purity and moral integrity. In India, gold is the preferred material for wedding jewelry, often with intricate designs and sometimes incorporating religious symbols.
Middle East
Middle Eastern ring designs frequently feature geometric patterns and may incorporate calligraphy. Gold is highly valued, with higher karat gold (18k, 21k, 24k) being preferred for its rich color and cultural significance.
Frequently Asked Questions About Ring Sizing
How do I know if my ring fits correctly?
A properly fitted ring should slide over your knuckle with slight resistance and then feel snug but comfortable on your finger. It shouldn't spin around excessively or leave deep marks on your skin. You should be able to remove it with some effort, but it shouldn't fall off when your hands are cold or wet.
What if I'm between sizes?
If you're between sizes, it's generally better to choose the larger size, especially for wider bands or if you live in a warm climate. For precious rings like engagement rings, consider having a jeweler create a custom size or add sizing beads to the interior for a more precise fit.
Can all rings be resized?
Most metal rings (gold, silver, platinum) can be resized, but there are exceptions. Rings made from tungsten, titanium, or stainless steel generally cannot be resized due to their hardness. Rings with intricate designs, eternity bands with all-around stones, or tension-set rings can be difficult or impossible to resize without affecting their structural integrity.
How much does ring size vary between fingers?
Ring size can vary significantly between different fingers. Typically, the ring finger is smaller than the middle finger but larger than the pinky. Your dominant hand's fingers are usually slightly larger than those on your non-dominant hand. It's best to measure each finger separately if you plan to wear rings on multiple fingers.
How do pregnancy and weight changes affect ring size?
Pregnancy, significant weight changes, and certain medications can cause temporary or permanent changes to your ring size. During pregnancy, fingers often swell, making rings tight or unwearable. If you experience substantial weight gain or loss (more than 10-15 pounds), your ring size may change by half a size or more.
Need More Help?
Professional Measurement
For the most accurate sizing, especially for important purchases like engagement or wedding rings, visit a professional jeweler. They have specialized tools to determine your exact ring size and can offer expert advice based on your specific needs.
Most jewelry stores offer free ring sizing as a service, even if you're not purchasing a ring from them.
Ring Sizer Kits
For at-home measurements, consider purchasing a ring sizer kit online. These kits typically include plastic or metal rings in various sizes that you can try on to find your perfect fit.
Some jewelry retailers offer free paper or plastic ring sizers through their websites - simply request one to be mailed to you.