Ring Size Guide

Get the Perfect Fit

Three ways to find your ring size — at home, on the go, or with our complimentary sizer by mail.

Method 1 — Measure at Home

You can find your approximate ring size in two minutes with a piece of string or a strip of paper.

Step 1: Wrap a thin strip of paper or string snugly around the base of the intended finger. Not too tight — the ring needs to slide over the knuckle comfortably.

Step 2: Mark where the strip overlaps with a pen.

Step 3: Lay the strip flat and measure the length in millimeters from the end to your mark.

Step 4: Match the measurement to the chart below to find your ring size.

Tips for accuracy: Measure at the end of the day when your fingers are at their largest. Avoid measuring when your hands are cold (fingers shrink) or after exercise (fingers swell). Measure 2–3 times and take the average.

Method 2 — Printable Ring Sizer

Download our printable ring sizer and measure from home. Place an existing ring that fits well over the circles to find your match, or cut out the paper strip and wrap it around your finger.

Important: Print at 100% scale (do not select "fit to page"). Confirm the measurement check on the printed sheet matches before using.

Download Printable Sizer (PDF) →

Complimentary Sizer by Mail

Want to be certain? We'll send you a free ring sizing kit — a set of plastic sizer rings in half-size increments. Try them on at home, find your perfect fit, and build your ring with confidence.

Allow 3–5 business days for delivery within the US. The kit is yours to keep.

Form fields:

  • First name

  • Last name

  • Shipping address

  • Email

Button: Request Your Free Sizer

Size Conversion Chart

US Size

Inside Diameter (mm)

UK Size

EU Size

4

14.9

H

46.8

4.5

15.3

I

48.0

5

15.7

J ½

49.3

5.5

16.1

K ½

50.6

6

16.5

L ½

51.9

6.5

16.9

M ½

53.1

7

17.3

N ½

54.4

7.5

17.7

O ½

55.7

8

18.1

P ½

57.0

8.5

18.5

Q ½

58.3

9

18.9

R ½

59.5

9.5

19.4

S ½

60.8

10

19.8

T ½

62.1


Helpful Sizing Notes

Wider bands fit tighter. If you're choosing a band wider than 4mm, go up a half size from your measured size. The wider the band, the snugger it feels.

Your dominant hand is usually slightly larger. If the ring is going on your left hand, measure that hand specifically.

It's okay to be between sizes. We recommend sizing up to the nearest half size for comfort. A slightly loose ring is easier to live with than a tight one.

We offer complimentary resizing within the first year if the fit isn't perfect. After the first year, resizing is available through our Lifetime Care program.

 

Sized and ready. Time to find your ring.


Build Your Ring → (LINK TO BUILD YOUR RING)

 

FAQs

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Yes. Apply your discount or trade-up credit first, and finance the remaining balance through Affirm.

Once we process your return, Affirm cancels the loan. Any payments already made are refunded to you. The process typically takes 5–10 business days.

Affirm sets its own minimums and maximums. Most Diamondaire purchases fall well within their range. You'll see financing availability confirmed at checkout.

Yes. Affirm is available at checkout for any order on our site, including custom ring builds.

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