Find the mattress size that fits your life

Answer four quick questions. Results update as you go.

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A starting point based on published sizing advice, not a guarantee. "Tight" means less than 24 in of walkway but at least 12 in (our cut-off). Leave the room size blank to skip the room check.

Mattress sizes, made simple

Twin to California king in inches and centimeters, plus a quick finder that weighs who sleeps in the bed, how tall you are and how big your room is. Every figure links to its source.

See the size chart

Inches and cm
Sources on every figure
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Two parents, two young children and a golden retriever laugh together on a king bed in a bright bedroom with a beamed ceiling and big windows

At a glance

Standard mattress sizes

Drawn to scale.

Size	Inches	Centimeters	Best for
Twin	38 × 75 in	97 × 191 cm	Kids, teens and single adults under 6 ft.
Twin XL	38 × 80 in	97 × 203 cm	Teens and single adults over 6 ft.
Full	54 × 75 in	137 × 191 cm	Single adults under 6 ft; a couple only in a pinch.
Queen	60 × 80 in	152 × 203 cm	Couples without kids or pets in the bed.
King	76 × 80 in	193 × 203 cm	Couples who want the most width, or share with a child.
California king	72 × 84 in	183 × 213 cm	Taller couples, or couples sharing with a pet.

Sizes and who they suit from a sleep-research site's size guide.^{[1 · Oct 29, 2026]} Thickness isn't standard and varies by model.^{[1 · Oct 29, 2026]} Full chart with split king, Olympic queen and cm

Room to breathe

How much space to leave around a bed

24 inwalkway on each side and at the foot^{[2 · Oct 29, 2026]}

30–36 inwhere a bedroom starts to feel open^{[2 · Oct 29, 2026]}

+5 ina frame can add in each direction^{[2 · Oct 29, 2026]}

10′ × 10′one maker's minimum room for a queen; 12′ × 12′ for a king^{[2 · Oct 29, 2026]}

Room sizes for every bed, and how to check yours

A couple relaxes on a queen bed with a book and coffee while a cat naps beside them in a sunny, lived-in bedroom

Side by side

Queen, king or something in between?

Queen vs full: a queen is 6 in wider and 5 in longer.^{[1 · Oct 29, 2026]}
King vs California king: 4 in wider vs 4 in longer.^{[1 · Oct 29, 2026]}
Twin vs twin XL: same width, 5 in more length.^{[1 · Oct 29, 2026]}

A couple unrolls a new queen foam mattress onto an oak platform frame, its shipping box on the floor and their dog nosing in to help

Bed in a box

Buying a mattress online

Boxes are about the size of a mini-fridge but can weigh up to 139 lb, so bring a helper.^{[3 · Oct 29, 2026]}
Unroll it on the frame, then remove the plastic.^{[3 · Oct 29, 2026]}
Full size can take up to about 72 hours.^{[3 · Oct 29, 2026]}

Mattress-in-a-box buying guide

Two movers carry a plastic-wrapped mattress on its edge up a staircase while a family and their corgi watch from the landing

Delivery day

Will it make it up the stairs?

Measure doorways, hallway turns and stair landings first.^{[2 · Oct 29, 2026]}
Split foundations in two halves can get up tight stairs where a one-piece foundation won't.^{[2 · Oct 29, 2026]}

Doorways, stairs and tight turns

A mother and her teenager snap a flat sheet over a queen bed while a cat watches from a bench at the foot of the bed

Bedding

Sheets that stay on

Match the sheet size to the mattress, then the pocket depth to its thickness. Standard pockets fit about 7 to 14 in; extra-deep pockets fit 16 to 24 in.^{[4 · Oct 29, 2026]}

Sheet sizes and pocket depth · Bed frame sizes

Guides

Everything about mattress sizes

Sources: 1. Sleep Foundation, Mattress sizes and dimensions guide. 2. Casper, Queen size bed dimensions: size, room fit, and how it compares. 3. Casper, How do Casper mattresses ship?. 4. Sleep Foundation, Bed sheet sizes. Checked Oct 29, 2026. Trademarks belong to their owners; figures are restated in our own words and tables, not reproduced.