Cock Ring Size Guide: How to Measure + Steel Size Chart

The right size is the difference between a ring you forget you're wearing and one you can't wait to take off. Too loose and it does nothing. Too tight and it's uncomfortable at best.

This guide shows you how to measure at home, gives you a size chart in mm and inches for our stainless steel cock rings, and explains what changes between steel and silicone.

The short version

• Measure the circumference at the base of your shaft, then divide by 3.14. That's the diameter you need, in mm.
• Steel doesn't stretch. Pick the closest size, and if you're between two, go larger.
• Not sure? Start with a stretchy silicone ring and move to steel once you know your size.

How to measure your cock ring size

You need a soft measuring tape, or a piece of string and a ruler.

1. Wrap the tape or string around the base of your penis, where the ring will sit. It should be snug, not tight.
2. Note the circumference in mm (cm × 10). If you used string, pinch the point where it meets, lay it flat and measure it against the ruler.
3. Divide by 3.14 to get the diameter. Example: 130 mm ÷ 3.14 ≈ 41 mm.
4. Repeat two or three times. Measure soft first, then semi-erect if you can, to see your range.

Cock ring sizes refer to the internal diameter, not the circumference. Mixing the two up is the most common sizing mistake.

As a starting point, choose a diameter equal to or slightly larger than your soft measurement. Most people land somewhere between 40 and 55 mm for a ring worn at the base of the shaft, but bodies vary, so treat that as a range, not a rule.

Stainless steel cock ring size chart

Here are the sizes we sell, with the inner circumference of each ring so you can compare it directly with your measurement.

Stainless Steel Curved Cock Ring

Internal diameter	Inches	Inner circumference
39 mm	1.53 in	≈ 12.3 cm
42 mm	1.65 in	≈ 13.2 cm
46 mm	1.81 in	≈ 14.5 cm
48 mm	1.89 in	≈ 15.1 cm
51 mm	2.00 in	≈ 16.0 cm

Stainless Steel Contoured Cock Ring

Internal diameter	Inches	Inner circumference
40–42 mm	1.57–1.65 in	≈ 12.6–13.2 cm
45–47 mm	1.77–1.85 in	≈ 14.1–14.8 cm
50–52 mm	1.97–2.05 in	≈ 15.7–16.3 cm
55–57 mm	2.17–2.24 in	≈ 17.3–17.9 cm

The contoured ring is listed in ranges because of its shape: one side is slightly wider than the other, so each ring has two slightly different internal diameters.

Curved or contoured: which steel ring?

The curved ring has a smooth, gently curved profile and a polished finish. It comes in five single sizes, which makes it easier to match to your measurement.

The contoured ring is made of 304 stainless steel with a subtly bent, ergonomic shape. It's rust-resistant and non-porous. If you're between two sizes, the range sizing gives you a little more tolerance.

You can see both, plus other options, in our cock ring collection.

Steel vs silicone: how sizing is different

Silicone stretches, so a slightly wrong size usually still works. Steel is rigid and has a fixed internal diameter, so sizing matters much more.

If you've never worn a cock ring, start with a stretchy silicone cock ring set. You can try different levels of snugness, then use what you learn to pick a steel ring in the right size. For the full pros and cons, read steel vs silicone cock rings.

Cock and ball ring size

A ring worn around both the penis and the testicles needs to be larger than a base-only ring, and it has to pass over the testicles. A rigid ring can't stretch to make that easier, so for this style we recommend an elastic silicone ring rather than steel. Our steel rings are sized to sit at the base of the shaft.

Common sizing mistakes

• Going for the smallest size. Tighter isn't better. A ring should feel secure, never painful.
• Mixing up circumference and diameter. Ring sizes are diameters. If you pick a size using your circumference, you'll end up with a ring far too large.
• Measuring once. Measure two or three times, and check both soft and semi-erect.
• Starting with steel when you don't know your size. Start with silicone, then upgrade.
• Wearing it too long. Even with the right size, a ring is for a session, not for the whole evening.

Signs your cock ring is too tight

Take the ring off right away if you notice:

• Numbness or tingling
• Pain or a feeling of pressure that keeps building
• Coldness, or skin that turns dark, blue, purple or pale

Most guidance suggests wearing a ring for no more than about 30 minutes, and never falling asleep with one on. A little water-based lube helps you slide a ring off. If you can't remove it, or you have pain or colour changes that don't go away, seek urgent medical help and don't wait.

Using a cock ring with a penis pump

If you use a pump, ring size matters even more, because the ring has to hold what the pump creates. We cover the most common problems in Penis Pump Not Holding Erection Even with Cock Ring? Causes & Solutions.

FAQ

What size cock ring do I need?

Measure the circumference at the base of your shaft and divide by 3.14. The result is the internal diameter you need, in mm. Most people fall between 40 and 55 mm for a base-of-shaft ring.

What if I'm between two sizes?

Go larger. A slightly loose ring is only less effective. A ring that's too tight can be dangerous.

Do steel cock rings stretch?

No. A stainless steel ring is rigid, so the size you buy is the size you get. That's why a size chart matters more than with silicone.

Should I measure soft or erect?

Start with your soft measurement, then check it semi-erect. The ring should go on comfortably before you're fully erect and shouldn't squeeze once you are.

Are stainless steel cock rings good for beginners?

They're safe for healthy adults when the size is right, but beginners are usually better off starting with silicone, which forgives a wrong size. See How Does a Cock Ring Work? for the basics.

How long can I wear a cock ring?

Most guidance says no more than about 30 minutes. Remove it immediately if you feel pain, numbness or any change in colour.

Final thoughts

Measure twice, divide by 3.14 and choose by internal diameter. If you're unsure, size up or start with silicone. When you're ready for steel, choose the Curved Cock Ring or the Contoured Cock Ring in the size from the chart above.

Want to know what to expect once it's on? Read Do Cock Rings Make You Last Longer?