About BedSizeGuide

BedSizeGuide gives the standard US mattress size chart -- width and length in inches, centimeters and square feet, for Twin through California King plus the less-common Full XL and Olympic Queen -- and a tool that checks which of those sizes actually fit a room you describe, with or without walking space around the bed.

Where the numbers come from

Every dimension on this site is cited to Better Sleep Council (Specialty Sleep Association / International Sleep Products Association), "Mattress Sizes" (fetched 2026-10-01) and cross-checked against Tampa Mattress Factory, "Mattress Size Chart: Standard, RV & Custom Sizes" (fetched 2026-10-01), which matches the Better Sleep Council's figures exactly on every standard size and is this site's source for Full XL and Olympic Queen, which the Better Sleep Council page doesn't list. Centimeter conversions use the exact international definition of the inch. Exact by international definition: the 1959 International Yard and Pound Agreement fixes 1 inch = 2.54 cm exactly (not a measured or rounded figure).

What this site leaves out, on purpose

"Alaskan King" and other oversized specialty names are sometimes quoted around 108 in x 108 in on retailer blogs, but no primary source this build could actually fetch and read gave a verifiable dimension for one -- the pages checked were either paywalled, rendered their chart as an image, or built it client-side with JavaScript rather than readable text. Rather than repeat an unverified number, it's left off this site entirely.

What the room-fit tool does and doesn't do

It checks a mattress's footprint, and separately its footprint plus your chosen clearance, against the room dimensions you enter, assuming the headboard sits against one wall. It doesn't know about your door swing, closet, windows, or furniture -- it's a starting estimate, not a substitute for measuring your actual room.

Who built this

BedSizeGuide is built and maintained by Elbert Ballo. The standard sizes don't change often, but this page and its sources are revisited periodically for accuracy.

Corrections

If a dimension here looks wrong, email hello@bedsizeguide.com. Sources are named on the chart page so a correction can be checked against them directly.