Eastern King vs California King: Same Size, Different Name

This is a short page because the answer is simple: Eastern King and Standard King are the same mattress. Both refer to the ISPA-standard 76 by 80 inch size, the most common King-class mattress in the US market. The name 'Eastern King' is used in some West Coast retail contexts to distinguish from California King. Everywhere else, the same mattress is just called King or Standard King.

If you have been shopping and seen Eastern King quoted alongside California King and Standard King, this page exists to confirm what you suspected: Eastern King and Standard King are the same size. Pick by dimension, not by name.

California King was introduced in the 1960s by Los Angeles-area mattress retailers. Demand came from buyers who wanted longer beds (to match the wider Hollywood-era beds and the new master-bedroom layouts of postwar California construction). The new 72 by 84 inch size needed a name to differentiate from the existing 76 by 80 inch king mattress that had been the US standard for decades.

The original 76 by 80 mattress got the regional clarifier 'Eastern King' because that was the historic East Coast and Midwest standard before California King existed. The new size got 'California King' or 'Western King' (the latter rarely used today).

By the 1990s, California King was widely distributed nationally and the 'Eastern' vs 'Western' regional framing fell out of common use, replaced by 'Standard King' (76 by 80) and 'California King' (72 by 84). The 'Eastern King' name persisted in West Coast retail use and in some retailer catalogs where Cal King is the default and the older size needs explicit naming.

When shopping, always confirm dimensions in inches, not the size name. If a product is labeled Eastern King, confirm 76 by 80. If it is labeled California King, confirm 72 by 84. Confusion between Eastern King and California King is one of the more common consumer mistakes in mattress purchase, leading to wrong-sized sheets, frames, and bedding.

The two sizes share area but differ in shape. They are NOT interchangeable for accessories. See sheets and bedding for the full accessory-compatibility guide.

For completeness, here is the broader US king-class naming reference:

• King / Standard King / Eastern King: 76 by 80 inches. The most common US king size.
• California King / Cal King / Western King: 72 by 84 inches. The longer, narrower alternative.
• Split King: Two Twin XL mattresses (38 by 80 each) on a king platform.
• Split California King: Two XL Twin mattresses (36 by 84 each) on a Cal King platform.
• Wyoming King: 84 by 84 inches. Custom non-ISPA size.
• Texas King: 80 by 98 inches. Custom non-ISPA size.
• Alaskan King: 108 by 108 inches. Custom non-ISPA size, largest mainstream format.
• Alberta King: 96 by 96 inches. Custom non-ISPA size, less common.

For comparisons among the custom sizes, see Wyoming King vs Cal King, Texas King vs Cal King, and Alaskan King vs Cal King.

For international king sizes (UK Super King, EU King, Australian King), see dimensions exact.