Why this pair matters
California King is not simply a larger King. It exchanges four inches of width for four inches of length.
The figures above are calculated from the identified dimensional records, not from rounded display conversions.
US King is 10.2 cm wider and 10.2 cm shorter than US California King.
The calculated surface-area difference is 0.5%, measured relative to US California King.
Width A − B+10.2 cm
Length A − B-10.2 cm
Area A − B+0.5%
Dimensions side by side
| Market + name | Native figure | Centimetres | Inches | Evidence type |
|---|---|---|---|---|
| US KingAlso: Eastern King | 76 × 80 in | 193 cm × 203.2 cm | 76 in × 80 in | conventionhigh confidence |
| US California KingAlso: Cal King, Western King | 72 × 84 in | 182.9 cm × 213.4 cm | 72 in × 84 in | conventionhigh confidence |
Compatibility decision
Regular King is wider; California King is longer. Their bedding and frames are not interchangeable by name.
Rigid frames, enclosed bases, fitted sheets and protectors should be selected from finished product measurements and depth—not from the closest name.
Check the underlying records
Review US King dimensions and tolerance · Review US California King dimensions and tolerance · Compare another country-qualified pair · Measure before buying
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.