16G vs 18G Earrings: What’s the Difference?

If you're shopping for flatback earrings or cartilage jewelry, you've probably come across sizes like 16G and 18G. But what do these numbers actually mean—and which one should you choose?

The “G” stands for gauge, which refers to the thickness of the earring post. Unlike many sizing systems, a smaller gauge number means a thicker post.

16G vs 18G at a Glance

The difference between them is only 0.2mm, so visually they can look very similar. However, that small difference matters when you're choosing jewelry for an existing piercing.

What Is a 16G Earring?

A 16G earring has a 1.2mm-thick post. 16G is commonly used for many cartilage piercings and is a popular size for flatback jewelry. If your piercing was originally made with 16G jewelry, choosing another 16G piece helps maintain the existing piercing size.

At A Pierce of Life, 16G (1.2mm) is our main flatback size, with many designs available in different post lengths so you can choose a fit that works with your anatomy and piercing placement.

What Is an 18G Earring?

An 18G earring has a 1.0mm-thick post, making it slightly thinner than 16G. It can be a good option for certain lobe and cartilage piercings, particularly if you're already wearing jewelry with a finer post.

Because piercing anatomy and existing jewelry sizes vary, it's always best to check the gauge you're currently wearing rather than choosing based only on the piercing location.

Should I Choose 16G or 18G?

The most important rule is simple: choose the gauge that matches your existing piercing.

If you're currently wearing a 1.2mm post, choose 16G. If you're wearing a 1.0mm post, choose 18G. For a healed piercing, you generally shouldn't force a thicker post through a piercing that has settled around thinner jewelry.

If you're unsure what gauge your piercing was made with, ask your piercer before changing jewelry.

Gauge Is Different From Post Length

Gauge tells you how thick the post is. Post length tells you how long it is.

At A Pierce of Life, many of our flatback earrings are available in 5mm, 6mm and 8mm post lengths. 5mm offers a snug fit for thinner anatomy, some tragus placements and thin lobes; 6mm is our standard option for many healed lobe and helix piercings; and 8mm provides additional room for thicker anatomy or piercings that need more space.

The ideal length depends on your individual anatomy, so two people wearing the same 16G earring may still need different post lengths.

Why Choose Flatback Earrings?

Unlike traditional butterfly backs, flatback earrings sit flat against the back of the ear. This creates a smoother profile with no sharp post sticking out behind the piercing.

They're particularly popular for curated ear stacks and placements such as the lobe, helix, forward helix, tragus, conch and flat. A Pierce of Life flatbacks are designed with comfortable everyday wear in mind, with internally threaded posts and multiple length options available across many designs.

The Bottom Line

The difference between 16G and 18G is the thickness of the post: 16G = 1.2mm and 18G = 1.0mm.

Neither is universally better. The right choice is the one that matches your piercing. Once you know your gauge, you can focus on finding the right post length and design for your ear—and start building an ear stack that feels as comfortable as it looks.