Flat-back earring post length: how to choose a replacement

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Buying the shortest available post is not a shortcut to a neater appearance. Your goal is a suitable fit with compatible parts, not the smallest number in a dropdown.

Which dimension is post length?

For a straight flat-back stud, look for the maker's diagram of the wearable shaft between the front and the back disc. Do not measure across the decorative front and include its stone or raised setting. The maker's measurement convention should govern the order.

For example, Cords Club's Postage Stamp listing separates a 6 mm post, a 4 mm back disc and a 5.4 by 3 mm decorative shape. Those three measurements describe different parts of the same stud.

A larger decorative front does not necessarily give you a longer post. Likewise, changing the disc diameter is not the same as changing the wearable length.

Sources 1

Use an existing fit as a reference

1. Find the original order or fitting note for the specific earring.
2. Record the post length and gauge separately.
3. Identify the closure and the compatible decorative end.
4. Ask whether the replacement listing includes only the post or a complete stud.
5. Keep the saved record with the new order so the next replacement is straightforward.

If two similar posts are loose in a drawer, do not assume you can identify their lengths by eye. Label them only when the measurement or original record is reliable. Otherwise, bring both to a piercer.

When copying the old length is the wrong move

Copying works best when the existing piece is known to fit and nothing relevant has changed. It is a poor shortcut when the current earring feels tight, sits differently, or was originally fitted for a piercing that was still healing.

The APP explains that appropriate jewelry length depends on anatomy and placement; jewelry that is too small or too large can cause problems. This guide is for understanding an order, not diagnosing a fit from a photo.

Do not turn a shop's suggested downsize schedule into a personal deadline. Arrange a fitting review when needed rather than making a size change simply because a certain number of weeks has elapsed.

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A message that gets a useful answer

Send the seller your model name, original size, order number and the part you need. For example: “I have this threadless front and want to replace its existing post with the same confirmed size. Which post in your range is compatible, and is the back disc attached?”

That asks about a specific component without asking customer service to infer your anatomy. If you need a different fit, a piercer can address that part in person.

Once you know the correct dimensions, our flat-back parts explainer can help you distinguish a complete stud from a decorative end before you buy.