What gauge is a standard earring post?

Most pierced earrings use a 20 gauge post, which is 0.8 mm in diameter. Cartilage and threaded flat-back studs often use 18 gauge at 1.0 mm, and 16 gauge at 1.2 mm is common for initial piercings and heavier ends.

Why do my earrings feel tight after a few hours?

The post is usually too short for the lobe, not too thin. A lobe measures 6 to 10 mm front to back, and a 9 mm post leaves almost nothing for the back once the earring front is counted.

Are screw backs better than butterfly backs?

They hold more securely and suit earrings worn for days, but the threads strip if you overtighten them. Butterfly backs are faster to remove and loosen with repeated use.

Jewelry

Earring Post Gauge and Backs: The Millimetres That Decide Comfort

Post gauge, post length and back type decide whether an earring sits flat or aches by noon. The numbers to check before you buy a pair.

Reviewed by Tessa Marlow · Updated Oct 17, 2026

The numbers first

A 0.8 mm post and a 1.2 mm post both pass through a standard piercing.
A 0.8 mm post fits a piercing made with a standard needle because that is the size the needle leaves behind.
Going up to 1.0 mm in a healed lobe is comfortable for most people.
The lobe measures roughly 6 to 10 mm from front to back, depending on thickness and on how high the piercing sits.

A 0.8 mm post and a 1.2 mm post both pass through a standard piercing. The difference shows up after four hours, not in the mirror. Gauge, length and back type are three separate numbers, and most listings publish only one of them.

Gauge is thickness, and 20G is the default

Earring posts are sold by wire gauge, where a larger number means a thinner post. The three sizes worth knowing:

A pair of gold drop earrings hanging on a white display stand

Gauge	Diameter	Typical use
20G	0.8 mm	Standard studs and drops
18G	1.0 mm	Cartilage, threaded flat backs
16G	1.2 mm	Initial piercings, heavy ends

A 0.8 mm post fits a piercing made with a standard needle because that is the size the needle leaves behind. Going up to 1.0 mm in a healed lobe is comfortable for most people. Going up in a fresh piercing is not, and no back style makes it so.

Post length matters more than gauge

The lobe measures roughly 6 to 10 mm from front to back, depending on thickness and on how high the piercing sits. A standard post runs 9 to 11 mm. Subtract the earring front, which can be 1 to 3 mm deep, and the remaining post has to clear the lobe plus the back.

A 9 mm post on a 10 mm lobe leaves nothing. The back presses into the skin, the earring tilts forward, and the pressure shows up as a dull ache by mid-afternoon. If a pair feels tight but not painful, measure the post before blaming the metal.

The back decides how it stays on

Back type	Hold	Best for	Fails when
Butterfly (friction)	Light	Studs under 2 g	Post is short or bent
Screw	High	Studs worn for days	Threads strip if overtightened
Lever back	High	Drops and hoops	Hinge loosens with use
Threaded flat back	High	Sleeping, cartilage	Needs a 1.0–1.2 mm post
Huggie hinge	Medium	Small hoops	Spring weakens after a year

Butterfly backs rely on friction against a notch near the post tip. Once that notch wears, the back slides. A silicone disc behind the butterfly adds grip for a few dollars and is the cheapest fix in the drawer.

Weight is what pulls a lobe down

A stud under 2 g stays where it is put. A drop past 4 g rotates forward on the post, and the piercing hole takes the load rather than the lobe. Wide, thin earrings spread that load better than a narrow heavy one at the same weight, which is why a 3 cm hoop can feel lighter than a 1 cm solid ball. A 6 g drop on a 0.8 mm post will tilt within an hour, no matter how tight the back.

Metal choice sets the floor: sterling silver is 10.4 g per cubic centimetre, 14k gold about 13 to 14, and solid 18k closer to 15.5. Hollow construction cuts the weight without changing the look. Vermeil sits between the two on cost, with a gold layer measured in microns over silver.

Read the listing for three numbers

Post gauge, post length and metal. If a listing gives none of them, the pair is a guess. Silver grades and ring sizing follow the same rule: the millimetre figure tells you more than the word “hypoallergenic” ever will.

FAQ

What gauge is a standard earring post?: Most pierced earrings use a 20 gauge post, which is 0.8 mm in diameter. Cartilage and threaded flat-back studs often use 18 gauge at 1.0 mm, and 16 gauge at 1.2 mm is common for initial piercings and heavier ends.
Why do my earrings feel tight after a few hours?: The post is usually too short for the lobe, not too thin. A lobe measures 6 to 10 mm front to back, and a 9 mm post leaves almost nothing for the back once the earring front is counted.
Are screw backs better than butterfly backs?: They hold more securely and suit earrings worn for days, but the threads strip if you overtighten them. Butterfly backs are faster to remove and loosen with repeated use.

Second Look

Every figure used above, with the section it appears in. If a number here does not match the page you are reading, trust the page — and tell us.

0.8 mm: Introduction
1.2 mm: Introduction
20G: Gauge is thickness, and 20G is the default
18G: Gauge is thickness, and 20G is the default
1.0 mm: Gauge is thickness, and 20G is the default
16G: Gauge is thickness, and 20G is the default
10 mm: Post length matters more than gauge
11 mm: Post length matters more than gauge

Tessa Marlow

Writes about garment construction, leather goods and footwear specs. Started in retail floor management before moving to editorial research. Our standards.