You can measure your ring size accurately at home using a strip of paper or string, a ruler, and five minutes, or by measuring the inside diameter of a ring you already own. Both methods, done correctly, get you within a fraction of a size of an in-store measurement.
Buying a ring online means skipping the one step a jewelry counter normally handles for you: sizing. That can feel like the riskiest part of the process, but it doesn't have to be.
Finger size is just a measurement, and with the right method and a few minutes of care, you can get it right from your kitchen table. This guide walks through the two most reliable at-home methods, a full size conversion chart, and the small details that actually affect accuracy.
Before You Start: What You'll Need
- A strip of paper or non-stretchy string : about 6 inches long, roughly ¼ inch wide if using paper
- A ruler with millimeter markings : most standard rulers include both mm and inches
- A pen : to mark where the strip overlaps
- An existing ring (optional) : if you'd rather measure a ring that already fits instead of your finger directly
Both methods below take under five minutes. Do whichever one you have the tools for right now, though measuring an existing ring tends to be slightly more accurate since it removes finger squeezing from the equation.
Method 1: The String or Paper Strip Method
This is the most common at-home sizing method, and it works well as long as you're careful not to pull the strip too tight.
- Cut a strip of paper or string About 6 inches long and, if using paper, roughly ¼ inch wide with a straight, clean edge.
- Wrap it around the base of your finger Wrap around the finger you'll wear the ring on, at the point where a ring would normally sit, below the knuckle.
- Mark where it overlaps Hold the strip snug, but not tight enough to indent the skin, and mark the point where the end meets the wrapped strip with a pen.
- Lay the strip flat and measure Use your ruler to measure the distance from the start of the strip to your pen mark, in millimeters. This is your finger's circumference.
- Match it to the conversion chart Use the chart below to convert your circumference measurement into a standard ring size.
Method 2: Measure a Ring You Already Own
If you have a ring that already fits the intended finger well, measuring it directly is often more reliable than measuring the finger itself.
- Choose a ring that fits the correct finger Use a ring currently worn on the same finger as the one you're buying for, sizing varies between fingers and even between hands.
- Place it on a ruler Lay the ring flat and measure the inside diameter, straight across the inner circle, in millimeters.
- Double check with a printable sizer, if available Many jewelers offer free printable ring sizing charts online. Place the ring over the printed circles until you find the exact match.
- Match the diameter to the conversion chart Use the inside diameter (not circumference) column in the chart below.
Ring Size Conversion Chart
Use whichever measurement you took, circumference from Method 1 or inside diameter from Method 2, to find your size below.
| US Size | Circumference (mm) | Inside Diameter (mm) | UK / AU Size |
|---|---|---|---|
| 4 | 46.8 | 14.9 | H |
| 5 | 49.3 | 15.7 | J ½ |
| 6 | 51.9 | 16.5 | L ½ |
| 7 | 54.4 | 17.3 | N ½ |
| 8 | 56.9 | 18.1 | P ½ |
| 9 | 59.5 | 18.9 | R ½ |
| 10 | 62.1 | 19.8 | T ½ |
| 11 | 64.6 | 20.6 | V ½ |
| 12 | 67.2 | 21.4 | X ½ |
Shipping worldwide, we know most of our customers aren't sizing in US standards. For a complete breakdown across US, UK, EU and Asian sizing systems, see our full International Sizing Guide.
Small Details That Change Your Result
Ring sizing is sensitive to timing and conditions more than people expect. A few small factors can shift your measurement by half a size or more.
- Measure at the end of the day. Fingers are naturally smaller in the morning and swell slightly by evening, measuring in the afternoon or evening gives a more representative size.
- Avoid measuring in extreme temperatures. Cold fingers shrink slightly, hot or humid conditions cause swelling. Room temperature gives the most consistent reading.
- Account for wide or prominent knuckles. If your knuckle is noticeably larger than the base of your finger, size for a comfortable fit over the knuckle, not just the base, or consider a ring with slightly more flexibility.
- Wide bands fit tighter than thin bands. A wider band, like eternity or statement styles, takes up more surface area on the finger and typically needs to be sized up a quarter to half size from a thin band measurement.
- Your dominant hand tends to run slightly larger. Measure the actual finger you'll wear the ring on, not the opposite hand, even if it feels like an unnecessary extra step.
If your measurement lands exactly between two sizes, sizing up is generally the safer choice. A slightly loose ring can be resized down more easily and affordably than a ring that's too tight to comfortably remove.
Ready to Shop With Confidence
Once you have your size, you're ready to shop knowing your ring will fit the moment it arrives. Every GK Moissanites ring ships with GRA-certified moissanite, a precious metal certification and a lifetime warranty, so the only thing left to get right is the size, and now you know exactly how.
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Frequently Asked Questions
Is the string method as accurate as an in-store ring sizer?
It's very close when done carefully, typically within a quarter size. The main risk is wrapping the strip too tightly, which is why measuring three times and comparing results improves accuracy.
What if my finger size falls between two sizes on the chart?
Round up to the larger size. A ring that's slightly loose is a simpler and cheaper fix than one that's too tight, and most rings can be resized down more easily than up.
Do wider rings really need a different size than thin bands?
Yes. A wider band contacts more of the finger's surface, which makes it feel tighter than a thin band at the exact same size. Sizing up a quarter to half size is standard practice for wide styles like eternity bands.
Should I measure my finger in the morning or evening?
Evening is more reliable. Fingers are typically at their smallest in the morning and swell slightly throughout the day, so an evening measurement better reflects your average size.
Can I resize a ring after I receive it if I got it wrong?
In most cases, yes. Reach out through our returns and exchange process if your ring doesn't fit, sizing issues are common with online orders and easy to correct after the fact.
