Best King Mattresses

A standard king mattress measures 76 inches wide by 80 inches long. That is 16 inches wider than a queen at the same length, and 4 inches narrower but 4 inches shorter than a California king. King is the widest of the mainstream mattress sizes, which is why it is the common choice for couples who specifically want more shoulder room rather than more overall length.

By the commonly cited convention, two sleepers on a king get roughly 38 inches of width each, compared with about 30 inches each on a queen. That is about 8 more inches of personal space per person, which is often the deciding factor for couples upgrading specifically because they feel cramped on a queen rather than because they need more length.

A split king uses two twin XL mattresses placed side by side to form the same 76 by 80 inch footprint as a single king mattress, but lets each side move independently on a compatible adjustable base. It is a configuration, not a different overall size. None of the king mattresses in this catalog are sold pre-split; a split king setup requires two separate twin XL mattresses instead.

A king mattress alone is 76 by 80 inches, and the room needs meaningful extra space beyond that for walking room, a frame and nightstands. A commonly cited minimum is roughly 12 by 12 feet, larger than what a queen typically needs. Checking the Room Size and Clearance Calculator against your specific room is more reliable than relying on a general rule of thumb.

That depends on what you are short on: width or length. A king is 4 inches wider (76 vs 72 inches) while a California king is 4 inches longer (84 vs 80 inches). Couples who want more shoulder room generally prefer a king; taller sleepers who want more legroom, generally over about 6 foot 4 inches, often prefer the California king instead.