A California king mattress is 4 inches longer and4 inches narrower than a standard king size mattress. California kings require different sized sheets than standard kings.
A standard king size mattress is 4 inches wider than a California king, making it perfect for families whose children always seem to end up in their parents' bed. The California king was invented in the 1960s as a way for a large bed to fit into a smaller space. It quickly gained popularity and is still widely used today.
A standard king size bed has always been 76-inches wide and 80-inches long. A California king is 72-inches wide and 84-inches long.