Need to Measure Your Ring Size Right Now?
Hello, this is artisan Jun.
You found a beautiful ring online and you really want it — but you don’t know your ring size!
You want to measure as accurately as possible, but you don’t own a professional ring gauge. But you still want the ring!
In situations like this, many websites introduce an easy at-home method: wrapping a piece of string or thread around the finger where you plan to wear the ring.
This DIY ring sizing method works by measuring the circumference of your finger (which corresponds to the inner circumference of the ring). By measuring the length of the string and comparing it to a size chart, you can estimate your ring size.
But how accurate is this method, really? Let’s take a closer look.
Ring Size Chart – Japanese Ring Sizes and Actual Inner Diameter (mm)
| Ring Size (Japanese Standard) | Inner Diameter (mm) | Ring Size (Japanese Standard) | Inner Diameter (mm) | Ring Size (Japanese Standard) | Inner Diameter (mm) |
| JP: 1 | 40.8 | JP: 11 | 51.3 | JP: 21 | 61.8 |
| JP: 2 | 41.9 | JP: 12 | 52.4 | JP: 22 | 62.8 |
| JP: 3 | 42.9 | JP: 13 | 53.4 | JP: 23 | 63.9 |
| JP: 4 | 44.0 | JP: 14 | 54.5 | JP: 24 | 64.9 |
| JP: 5 | 45.3 | JP: 15 | 55.5 | JP: 25. | 66.0 |
| JP: 6 | 46.1 | JP: 16 | 56.6 | JP: 26 | 67.0 |
| JP: 7 | 47.1 | JP: 17 | 57.6 | JP: 27 | 68.1 |
| JP: 8 | 48.1 | JP: 18 | 58.6 | JP: 28 | 69.1 |
| JP: 9 | 49.2 | JP: 19 | 59.7 | JP: 29 | 70.2 |
| JP: 10 | 50.2 | JP: 20 | 60.7 | JP: 30 | 71.2 |
Based on the official Japanese Industrial Standards (JIS) for ring sizing.
Can You Really Measure It Accurately? How to Measure Your Finger Circumference
Now that you understand ring size numbers and inner diameter (the inside measurement of a ring), you might be wondering:
Can you really measure your finger circumference at home?
We’ve summarized a simple and reliable way to do it below.
What You’ll Need
・A thin string (something safe and comfortable to wrap around your finger)
・A marker
・A ruler
How to Measure Your Ring Size at Home
Step 1: Wrap the string around the widest part of your finger.
Wrap it snugly — not too tight and not too loose.
For some people, the base of the finger is the widest part. For others, it may be the knuckle. Measure whichever area is largest to ensure your ring can slide on comfortably.
Step 2: Mark where the string overlaps.
Step 3: Measure the length between the marks.
Lay the string flat and measure the distance between the two marks using a ruler.
In theory, this method should give you an accurate ring size measurement.
But does it really work?
We thoroughly tested various types of string materials to see how accurate this method truly is.
Ring Size Accuracy Across Various Materials
My ring size is Japanese size 11, so if the measurement comes out to 51.3mm, that means it’s correct — but will it match? Let’s find out!
Measuring Your Ring Size with A Thin Strip of Paper
I found a regular sheet of printer paper at home — something almost everyone should have. Standard A4 or letter-size paper works perfectly for this simple ring size measuring method.
I cut the paper into a thin strip, approximately 5mm wide.
Next, I wrapped the strip around the finger. However, it was slightly difficult to wrap tightly and evenly.
After marking the overlap point, the measured length came out to 56mm.
When compared with the JIS (Japanese Industrial Standards) ring size chart, this measurement corresponded to approximately size 15–16.
Because regular printer paper is relatively stiff, it may not wrap snugly around the finger. For more accurate results, we recommend using a softer, more flexible material that can fit closely to the finger without gaps.
Measuring Your Ring Size with A Rubber Band
A rubber band is something most households have on hand, so I decided to test this method.
After wrapping it around the finger and measuring it with a ruler, the length came to 27mm.
However, the calculated size turned out to be extremely small—below size 1.
Even if you wrap it tightly and carefully, a rubber band is elastic, which can affect the accuracy of your measurement. For more reliable results, it’s best to use a non-stretchable material such as a thin string or paper strip when measuring your ring size at home.
Measuring Your Ring Size with A Ribbon
A ribbon is softer than paper and does not stretch like elastic—but how accurate will the results be?
I tried using a satin ribbon. Because of its smooth texture, it tends to slip easily, so it may be helpful to ask someone nearby to assist you while measuring.
When measured, the circumference came out to 54 mm.
This would correspond to approximately Japan ring size 13–14. However, it seems the ribbon we used was too wide. The ribbon measured 8 mm in width, which likely affected the accuracy.
Next, we will try measuring with a thinner material to see if we can achieve a more precise result.
Measuring Your Ring Size with An Embroidery Thread
Softer than paper, less stretchy than rubber, and thinner than a ribbon—embroidery thread turns out to be surprisingly reliable for measuring your ring size at home.
Looks promising!
When measured carefully, the circumference came out to 52mm.
That corresponds approximately to Japanese size No. 11–12.
So far, this method produced the measurement closest to the true ring size.
If you're looking for an easy and accurate way to measure your ring size at home, embroidery thread may be one of the best options to try.
Here’s What We Learned About Measuring Ring Size at Home
We tested measuring ring size using items commonly found at home. It seems that the best materials for wrapping around your finger are:
Soft and easy to wrap
Non-stretchable
Thin
However, the pressure used when wrapping and the material itself can vary from person to person.
While this is a quick and convenient DIY method, we found that it only provides an approximate ring size.
Determining an accurate size at home can be quite challenging.
At MITUBACI TOKYO, we offer a free rental of professional ring gauges that accurately measure sizes from JP 1 to 30. If you would like a precise measurement, we highly recommend using this service.
We also offer hands-on jewelry-making workshops, where you can create your own ring—from casual silver designs to solid gold wedding bands. Our skilled artisans will measure your finger size on the spot, so there’s no need to measure in advance. You can create a ring that fits perfectly from the very beginning.
For reservations and inquiries, please contact us here: https://www.mitubaci.co.jp/contact/
Bonus Edition
Extra: Trying Different Household Items to Measure Ring Size at Home
Wire
While it was easy to wrap around the finger, the wire bent unevenly and became misshapen.
Because it is relatively stiff, it may not provide an accurate measurement and is therefore not recommended for ring sizing.
Cable Ties
Cable ties have recently become a popular item in the world of DIY trends.
The process is simple — just wrap it around and tighten. However, due to the nature of cable ties, once tightened, they cannot be loosened again. If you fasten it too tightly, it may become difficult (or even impossible) to remove from your finger. A slightly risky choice!
Ball Chain
A ball chain is a type of metal chain commonly used for straps and keychains.
Because its surface is smooth and rounded, it can be difficult to engrave or add markings. We found that a slightly slimmer chain may work better for detailed customization.
If we come across any other interesting materials or components, we’d love to test and review them as well.
See you next time!
