What distinguishes it
The US King is materially wider than UK and Australian King conventions.
It is 4 inches wider and 4 inches shorter than a California King.
76 × 80 in
Metric193 cm × 203.2 cm
Imperial76 in × 80 in
Surface area3.92 m²
Market aliases: Eastern King.
+40.6 cm width · 0.0 cm length · +26.7% area
The area percentage uses US Queen as its denominator. It is 4 inches wider and 4 inches shorter than a California King. That difference can change whether a rigid frame opening or fitted bedding matches.
Not the same worldwide
It is 13.0 cm wider than a UK Super King and about 9.5 cm wider than an Australian King example.
Evidence type: convention · high confidence.
Before ordering
A named size is not a fit guarantee. Compare the seller’s finished width, length and stated tolerance with the frame opening and bedding specification.
Published tolerance: Nominal convention; check finished dimensions.
Measure the finished mattress and the frame’s internal opening. Measure the mattress correctly and check which frame dimension controls fit.
Continue this decision
Curated comparisonUS King vs California King size
Regular King is wider; California King is longer. Their bedding and frames are not interchangeable by name.
Curated comparisonUS King vs UK Super King sizeUS King is about 13 cm wider and 3.2 cm longer.
Curated comparisonKing mattress size by countryUS King is widest of the three selected conventions; UK King is the narrowest.
Related US recordUS QueenIt is 7 inches wider and 5 inches longer than this dataset’s sourced US Full convention.
Related US recordUS California KingIt is narrower and longer than a regular US King, so the names are not interchangeable for frames or bedding.
Related UK recordUK Super KingIt adds 30 cm of width over UK King without increasing nominal length.
Evidence for this answer
- Better Sleep Council — Mattress SizesChecked 27 August 2026. Minimum factual dimensions only; original wording, tables and visuals.
Correction route: If a current source or product specification conflicts with this page, send the page URL and evidence through the corrections process.