Is 18KP the same as 18K Plated?

Yes. 18KP, 18K Plated all denote the same material — gold-plated. Different markets and eras stamp it differently, but the purity is identical.

How do I confirm a 18KP stamp is genuine?

Look at the mark under 10× magnification for crisp, even strikes, cross-check the weight-to-volume ratio against the expected density, scan it with the Jewelry Identifier app, and — when it matters — have an XRF test done by an assay office or gemological lab.

* Gold-Plated hallmark

The 18KP hallmark: meaning, purity & value

18KP means 18K gold plated — a surface layer over base metal. Not solid 18K; scrap value is negligible.

Published May 30, 2026

Quick facts

Metal: Gold-Plated
Common regions: United States, Japan
Standard: ISO 9202

Stamps that mean the same thing

This purity may be struck into jewelry as any of: 18KP / 18K Plated. The mark differs by country and era, but the metal content is identical.

What 18KP tells you

18KP means 18K gold plated — a surface layer over base metal. Not solid 18K; scrap value is negligible.

How to check it yourself

Examine the stamp under a 10× loupe — genuine marks are crisp and evenly struck, not doubled or smeared.
Confirm the mark reads 18KP or an equivalent such as 18K Plated.
Photograph it in the Jewelry Identifier app to read the metal, hallmark, and any gemstones from the image.
For a binding result, have an assay office or gemological lab run an XRF purity test.

Sources

ISO 9202
Trade hallmark references

* Frequently asked

FAQ

Q. Is 18KP the same as 18K Plated?: A. Yes. 18KP, 18K Plated all denote the same material — gold-plated. Different markets and eras stamp it differently, but the purity is identical.
Q. How do I confirm a 18KP stamp is genuine?: A. Look at the mark under 10× magnification for crisp, even strikes, cross-check the weight-to-volume ratio against the expected density, scan it with the Jewelry Identifier app, and — when it matters — have an XRF test done by an assay office or gemological lab.

* Try it

Identify the jewelry in your hand, right now.

Just take a photo — AI reads the metal, gemstone, hallmark, era, and an estimated value range in seconds. First two scans free, no account required.

Identify your jewelry now — free App Store

* Related