What Does KP Mean on Jewelry?

KP stands for 'Karat Plumb' (or 'Karat Proof'). When you see 14KP or 10KP, it means the gold is a full, exact karat — historically, some 14K gold ran slightly under 14 karats, so 'plumb' was added to guarantee the piece meets the stated purity precisely. It's a sign of quality, not a lower or different metal.

What is a KP piece worth?

A KP mark is a quality assurance, not a different metal — 14KP is worth the same as solid 14K, just certified not to be under-karated.

How to verify a KP stamp

Scan the full stamp with the Hallmark Reader; KP simply confirms the karat number next to it is honest. Anyone can stamp a mark on metal, so a hallmark alone isn't proof — the fastest way to check is to photograph the stamp and run it through the free Hallmark Reader, then confirm the metal itself with the Is It Real? tool. For a full picture of what your piece is worth, get a free jewelry appraisal. To compare KP with every other mark side by side, see the full jewelry stamps and markings chart.

Frequently asked questions