Though the names are alike, a king and California king mattress aren’t the exact same size, nor are their individual sheets. A king mattress, also called an eastern warrior, is 5 inches wider and shorter than a California or western king mattress. Due to the difference in mattress sizes, sheets intended for a single type of king bed generally won’t fit well on the other. Both flat and fitted sheet sizes also vary based on brand.
A king mattress is 76 inches wide and 80 inches long, compared to California or western king, which is 72 inches wide and 84 inches long. While sheet sizes vary by brand and fashion, a fitted sheet is comparable to the respective mattress in dimensions; for example, 78 inches wide and 80 inches long to get a king mattress, compared to 72 inches wide, 84 inches long to get a California king. The sheet has a tiny bit of extra width at the king-sized set. Flat sheets are bigger: around 109 inches wide and up to 106 inches long for a king, compared to around 108 inches diameter and length for the California king. Flat sheet sizes differ greatly from one style into another. Some retailers offer size graphs so that you can determine which option best fits your needs.