From 20G to 14G: Making Sense of Piercing Jewelry Gauges

20G, 18G, 16G, 14G… For piercing professionals, these measurements are part of everyday work. Yet when gauges are combined with millimeters, post lengths and ring diameters, it can become surprisingly easy to confuse measurements that describe completely different things.

Understanding the gauge system does not have to be complicated. A few key references can make jewelry dimensions easier to read and ordering mistakes easier to avoid.

The most important thing to remember is simple: gauge indicates the thickness of the jewelry post — and the smaller the gauge number, the thicker the post.

What Is a Gauge?

Gauge, commonly abbreviated as G, is a measurement used to indicate the thickness of a jewelry post.

Unlike the metric system, its logic may seem reversed: a 14G piece has a thicker post than a 16G piece, and a 16G is thicker than an 18G. This convention comes from older wire measurement systems and remains widely used in piercing jewelry today.

Here are several common equivalents:

20G = 0.8 mm
18G = 1.0 mm
16G = 1.2 mm
14G = 1.6 mm

These few measurements cover many of the sizes commonly encountered in everyday piercing jewelry.

These equivalents are useful for understanding and converting measurements. They should not be used on their own to determine which gauge is appropriate for a particular piercing. That decision should always take anatomy, placement and professional assessment into account.

Gauge, Length and Diameter: Three Different Measurements

When reading jewelry dimensions, it is essential to distinguish between three measurements.

Gauge refers to the thickness of the post.

Length refers to the usable inside length of the post, between the balls or ends, on jewelry such as labrets, barbells and curved barbells.

Diameter is primarily used for rings, clickers and circular barbells and generally refers to the inside diameter of the jewelry.

Two pieces can therefore have exactly the same gauge while having different lengths or diameters. A 16G labret, for example, may be available in several lengths, while several 16G rings may have different inside diameters.

Gauge should also not be confused with the size of a ball, stone or decorative attachment. A 3 mm stone refers to the size of the stone, not the thickness of the jewelry post.

The Same Gauge Does Not Always Mean Compatible

Two pieces labeled with the same gauge are not necessarily interchangeable.

Gauge indicates post thickness, but compatibility also depends on the jewelry system, including internal or external threading, thread dimensions, threadless systems and attachment type.

A 16G labret and an attachment designed for another system may therefore share the same gauge without being compatible.

When a base and attachment are ordered separately, it is important to check the complete specifications rather than gauge alone — especially when a studio works with multiple jewelry systems.

Why a Few Tenths of a Millimeter Matter

The difference between 1.0 mm and 1.2 mm may seem small. In piercing jewelry, it is not.

An 18G piece and a 16G piece do not have the same post thickness and should not be considered interchangeable simply because the visual difference is subtle.

This precision is especially important when replacing jewelry or ordering a new piece. Gauge, like the other dimensions, should correspond to the piercing, anatomy and professional selection.

Read the Complete Size Before Ordering

Gauge represents only part of the information needed to select a piece of jewelry.

For a labret or barbell, check:

gauge + length

For a ring or clicker:

gauge + inside diameter

Depending on the design, the size of a ball, stone or decorative attachment may also be important.

This is particularly useful when ordering online. Two pieces may look almost identical in a photograph while having very different dimensions in person. Product photography shows the design, but it does not always communicate exact scale.

Taking a few extra seconds to check all measurements can prevent many mistakes when the jewelry arrives or is ready to be used.

Create Simple References in Your Studio

Even when working with jewelry every day, there is no need to memorize every conversion.

Organizing jewelry first by gauge and then by length or diameter can also make it easier to identify the correct dimensions and reduce the risk of mixing visually similar pieces.

And when a piece is no longer labeled or its size is uncertain, a caliper can help confirm the measurement rather than relying on visual estimation alone.

A Small Measurement That Makes a Big Difference

The gauge system becomes much easier once its basic logic is understood: as the gauge number decreases, the post becomes thicker.

But gauge is only part of the equation. Length, diameter and system compatibility also need to be considered when selecting the correct piece.

Gauge, length and diameter: three different measurements, three different decisions.

For studios, understanding these dimensions makes ordering easier, helps keep inventory organized and supports the selection of the right jewelry.

Because in piercing jewelry, a few tenths of a millimeter can make all the difference.

Explore Our Professional Piercing Jewelry

From labrets and barbells to rings, clickers and attachments, explore our professional piercing jewelry available in a variety of sizes and configurations.

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