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Alaskan King mattress dimensions

Alaskan King is the largest commonly sold oversized mattress: 108 by 108 inches in the cited US oversized profile.

Published by BedFit Atlas · Updated 2026-10-17

Dimensions at a glance

US · Nominal bed dimensions
Size	Width (in)	Length (in)	Area (sq ft)
Alaskan KingReviewed 2026-10-17	108	108	81

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1. Alaskan King

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Alaskan King is the largest commonly sold oversized mattress: 108 by 108 inches in the cited US oversized profile. That is 274.3 centimetres on each side, or 9 feet square, and the footprint covers 11,664 square inches, about 81 square feet.

Alaskan King compared with King

A standard King in the same profile is 76 by 80 inches, or 6,080 square inches. An Alaskan King adds 32 inches of width and 28 inches of length and covers about 1.9 times the area. Two adults have 54 inches each, the width of a whole Full mattress per person, which is why the size is marketed to families who share a bed with children or large dogs.

Room space for an Alaskan King

Consider the mattress length aligned to the room length, both sides open, one 20 by 20 inch nightstand, and side and foot clearances each set to 24 inches. An Alaskan King requires 176 inches across and 132 inches along the room. A 14 ft by 14 ft room is 8 inches too narrow across for that layout. A 16 ft by 12 ft room leaves 16 inches across and 12 inches along; a 16 ft by 14 ft room leaves 16 inches across and 36 inches along. These clearances are adjustable preferences for the worked example, not standards, and the room also has to hold wardrobes, doors and walking routes. A 9-foot square mattress often cannot turn a standard stair or hallway, so ask how the maker delivers it: in one piece, in sections, or compressed.

Bedding and frames

Everything around an Alaskan King is special order: frame, foundation, fitted sheets, duvet and protector. King bedding is 32 inches too narrow. Oversized sizes are not standardised across brands, so buy bedding for the specific mattress and confirm the frame's outside dimensions, which will exceed 9 feet.

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Sources and review dates

Data reviewed 2026-09-18.

Bed Sizes and Mattress Dimensions: Guide + Comparison Chart — Purple Purple, US mattress dimensions guide; selected nominal reference values, not product measurements or universal tolerances.
Oversized Mattress Sizes — Sleep Foundation Sleep Foundation, Oversized Mattress Sizes; numerical reference values, not product measurements or universal tolerances.
Published room-fit geometry, version 1 — Bed Dimensions