A standard king size mattress is typically 76 inches wide by 80 inches long (about 193 cm by 203 cm, or roughly 6.3 feet by 6.7 feet).

Quick Scoop

  • Standard king (a.k.a. Eastern king): 76" wide x 80" long.
  • In centimeters: about 193 cm x 203 cm.
  • In feet: about 6.33 ft x 6.67 ft.
  • Space per person: if two people share, each gets about 38" of width.

How that feels in real life

  • Imagine two twin‑size widths side by side; that’s roughly how wide a king feels.
  • It works best in bedrooms around 12 ft x 12 ft or larger so you still have room to walk around the bed comfortably.

If you’re taller than average and want more legroom than a standard king offers, a California king (about 72" x 84") trades some width for extra length.

Meta description (SEO):
Wondering how big is a king size mattress? A standard king measures about 76" x 80" (193 cm x 203 cm), offering generous space for couples and families in a 12' x 12' bedroom or larger.

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