Measuring a ring size at home with a ring sizer
STDIAM RING SIZE GUIDE

Find Your
Perfect Fit

A ring should feel secure and naturally comfortable. Measure at home, compare your result and choose your ideal STDIAM US ring size with confidence.

START MEASURING FIND MY SIZE
WHICH METHOD SHOULD I USE?
1

I Already Own a Ring

Measure the inside diameter of a ring that fits the same finger.

2

I Don't Have a Ring

Measure your finger circumference using paper or non-stretch string.

3

I'm Between Sizes

Choose the larger size for a little more comfort, especially with wider bands.

HOW TO MEASURE

Two Simple Ways to Find Your Size

Choose the method that matches what you have available. For greater confidence, repeat your measurement two or three times.

METHOD 1

Measure an Existing Ring

Best if you already own a ring that fits the same finger comfortably.

  1. 1Choose a ring that fits the intended finger comfortably.
  2. 2Place the ring flat on a ruler or measuring surface.
  3. 3Measure straight across the centre of the inner circle in millimetres.
  4. 4Measure only the open interior. Do not include the thickness of the metal.
  5. 5Match the inside diameter to the quick size finder below.
How to measure the inside diameter of an existing ring in millimeters
METHOD 2

Measure Your Finger

No ring available? Use a narrow strip of paper or a piece of non-stretch string and follow these three simple steps.

Wrap a paper strip around the base of your finger
WRAP

Wrap Around Your Finger

Wrap the paper comfortably around the base of your finger. It should feel secure but not tight.

Mark where the paper strip overlaps around your finger
MARK

Mark the Overlap

Mark the exact point where the two ends meet around your finger.

Measure the paper strip in millimeters with a ruler
MEASURE

Measure the Length

Unwrap the strip and measure from the starting edge to your mark in millimetres.

!
Crucial Fit Tip: Mind Your Knuckle

If your knuckle is noticeably larger than the base of your finger, measure both areas. Choose a size that passes comfortably over the knuckle without feeling too loose at the base.

QUICK SIZE FINDER

Match Your Measurement

Find the closest measurement below. Each card shows both measuring methods and the corresponding STDIAM US size.

Measured your finger?Use circumference.
Measured a ring?Use inside diameter.
US SIZE4
CIRCUMFERENCE46.8 mmDIAMETER14.9 mm
US SIZE4.5
CIRCUMFERENCE48.0 mmDIAMETER15.3 mm
US SIZE5
CIRCUMFERENCE49.3 mmDIAMETER15.7 mm
US SIZE5.5
CIRCUMFERENCE50.6 mmDIAMETER16.1 mm
US SIZE6
CIRCUMFERENCE51.9 mmDIAMETER16.5 mm
US SIZE6.5
CIRCUMFERENCE53.1 mmDIAMETER16.9 mm
US SIZE7
CIRCUMFERENCE54.4 mmDIAMETER17.3 mm
US SIZE7.5
CIRCUMFERENCE55.7 mmDIAMETER17.7 mm
US SIZE8
CIRCUMFERENCE57.0 mmDIAMETER18.1 mm
US SIZE8.5
CIRCUMFERENCE58.3 mmDIAMETER18.6 mm
US SIZE9
CIRCUMFERENCE59.5 mmDIAMETER18.9 mm
US SIZE9.5
CIRCUMFERENCE60.8 mmDIAMETER19.4 mm
US SIZE10
CIRCUMFERENCE62.1 mmDIAMETER19.8 mm
US SIZE10.5
CIRCUMFERENCE63.4 mmDIAMETER20.2 mm
US SIZE11
CIRCUMFERENCE64.6 mmDIAMETER20.6 mm
Between two sizes? Choose the larger size for slightly more comfort, particularly for wider bands.
GLOBAL CONVERSIONS

International Ring Size Chart

STDIAM rings are listed in US sizes. Compare your local sizing system below.

Measurement + STDIAM US Size stay visible. Swipe horizontally to compare international sizing systems.
Circumference
Inches		 Circumference
Millimeters		 STDIAM US SIZEUnited States,
Canada, Mexico		 United Kingdom,
Australia,
Ireland, New Zealand,
South Africa		 EUROPE / ISOFrance, Belgium,
Sweden, Denmark,
Finland, Norway, Austria		 DIAMETER SYSTEM
Germany, Netherlands,
Russia, Ukraine		 SWISS SYSTEM
Switzerland,
Italy, Spain		 ASIA / OTHER REGIONS
India, China, Japan,
South America,
Turkey, Israel
1.8446.84H47156 1/27
1.8948.04.5I4815 1/47 3/48
1.9449.35J 1/24915 3/499
1.9950.65.5K 1/250.516 1/410 1/410
2.0451.96L 1/25216 1/211 1/212
2.0953.16.5M 1/2531712 3/413
2.1454.47N 1/254.517 1/41414
2.1955.77.5O 1/25617 3/415 1/415
2.2457.08P 1/2571816 1/216
2.2958.38.5Q 1/258.518 1/217 3/417
2.3459.59R 1/259.5191918
2.3960.89.5S 1/26119 1/220 1/419
2.4462.110T 1/262.52021 1/220
2.4963.410.5U 1/263.520 1/422 3/421
2.5464.611V 1/26520 3/42422
← Keep the first three columns in view and swipe to compare countries →
PRO TIPS FOR THE PERFECT FIT
Fingers Change Size

Temperature, humidity and activity can affect finger size. Measure when your hands feel comfortably warm and normal.

Band Width Matters

Wider bands tend to feel more snug. If you are exactly between two sizes, consider choosing the larger size.

Measure More Than Once

Repeat your measurement two or three times. Consistent results give greater confidence before choosing your final size.

ADDED PEACE OF MIND

FREE RING
RESIZING

If your first size is not quite right, eligible STDIAM rings may receive one complimentary resizing request within 30 days of purchase. Certain designs and larger size adjustments may have technical limitations.

ASK ABOUT RESIZING →
STILL UNSURE?

We're Here to Help

Choosing between two sizes or buying a ring as a gift? Send us your measurements and the ring you are considering. Our team can help review the fit before you order.

CONTACT OUR TEAM →
RING SIZE QUESTIONS

Frequently Asked Questions

How should a properly fitted ring feel?+
A well-fitted ring should feel secure without feeling tight. It should slide over the knuckle with light resistance and sit comfortably at the base of your finger without spinning excessively.
What should I do if I am between two ring sizes?+
Choose the larger size when you are exactly between two sizes, especially for wider bands. If the two measurements differ noticeably, measure again before ordering.
When is the best time to measure my finger?+
Measure when your hands are at a comfortable normal temperature, ideally later in the day. Avoid measuring immediately after being very cold, hot or physically active.
Can I use an existing ring to find my size?+
Yes. Choose a ring that fits the same finger well and measure the inside diameter straight across the centre of the ring, from inside edge to inside edge.
Do wider ring bands fit differently?+
Yes. Wider bands usually feel more snug than delicate bands because more metal contacts the finger. If you are between sizes, the larger size is usually more comfortable.
What if I order the wrong ring size?+
Eligible STDIAM rings may receive one complimentary resizing request within 30 days of purchase. Certain designs and larger size changes may have technical limitations, so contact us before sending your ring back.
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