what size is a king size mattress

A standard king size mattress is typically 76 inches wide by 80 inches long (about 193 cm by 203 cm).

Quick Scoop: King Size Basics

• Standard king mattress: 76" x 80" (width x length).

• In feet, that’s roughly 6.3' x 6.7'.

• It’s the widest common mattress size and gives each of two sleepers about 38" of personal space.

Common King Variants (So You Don’t Mix Them Up)

• California King: about 72" x 84" – narrower but longer than a standard king, popular with taller sleepers.

• Other oversized “kings” (Texas, Wyoming, Alaskan) exist, but they’re specialty sizes and much larger than the standard king.

Real‑World Feel (Mini Story)

Imagine two twin XL mattresses pushed together side by side – that’s essentially the footprint of a standard king, which is why many adjustable beds use a split king layout. Couples who feel cramped on a queen often notice the extra 16" of width immediately when they upgrade to a king.

Room Size Tip

A king usually works best in a primary bedroom of at least about 12' x 12', so there’s still walking space and room for nightstands. If your room is tighter, a queen may fit circulation and furniture better.

TL;DR:
Standard king size mattress = 76" x 80" (about 193 cm x 203 cm). Anything longer (like 72" x 84") is usually a California King, not a regular king.

Information gathered from public forums or data available on the internet and portrayed here.