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King mattress dimensions

King is 76 by 80 inches in the cited US nominal profile.

Published by BedFit Atlas · Updated 2026-10-06

Dimensions at a glance

US · Nominal bed dimensions
Size	Width (in)	Length (in)	Area (sq ft)
KingReviewed 2026-09-18	76	80	42.2

King · US · Nominal mattress: 76 in × 80 in · 193 cm × 203.2 cm

AT THE SAME SCALE

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1. King

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Leave room around it.

King is 76 by 80 inches in the cited US nominal profile. Compare that mattress footprint with the outside dimensions of your actual frame before planning a room.

US King size in inches and centimetres

The reference above shows the same reviewed dimensions in both units. A unit change does not turn this US profile into another country's size system. Check the cited source and the actual product specifications before ordering.

King compared with Queen

The cited Queen is 60 by 80 inches. King adds 16 inches of width while keeping the same length. That wider footprint changes the space available beside the bed, especially when nightstands and walking space are included.

King compared with California King

The cited California King is 72 by 84 inches: four inches narrower and four inches longer than King. The name does not mean a larger footprint in every direction, and it does not establish that frames, bases or fitted bedding are interchangeable.

Check the frame and the complete room layout

Measure the widest and longest outside edges of the frame, including headboard, footboard and other projections. In the room calculator, enter those measurements, nightstands and your clearance preferences. Side clearance is outside the combined bed and nightstand footprint. The linked King versus Queen example uses a 12 ft square room and shows why a geometric fit can leave no spare width. Door swings, fixed furniture, transport routes and measurement uncertainty need separate checks.

Compare King vs Queen room space

Compare King vs California King room space

Check both orientations, nightstands and the walking space you want.

Check King in your room

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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.
Published room-fit geometry, version 1 — Bed Dimensions