Mattress Size Guide
The exact dimensions of every standard mattress size, in inches and centimetres, with a built-in check for whether the size fits your bedroom with room to walk.
Pick the size before you pick the bed
Size names are slippery: they change between countries, and a bed that looks fine in a big showroom can swallow a real bedroom once you add the walking space you need on either side. Starting from the actual dimensions — and checking them against your room — saves you from the two classic mistakes, a bed that crowds the floor and bedding bought to the wrong standard.
Once you have the size, use the Bedding Size & Fit Calculator to find the sheet and duvet-cover sizes it needs, or the Bed & Room Fit Plannerto check clearance against a specific bed frame’s footprint.
Frequently Asked Questions
What are the standard mattress sizes?
In the US the common sizes are Twin (38×75 in), Twin XL (38×80 in), Full (54×75 in), Queen (60×80 in), King (76×80 in) and California King (72×84 in). In the UK they are Single (90×190 cm), Small Double (120×190 cm), Double (135×190 cm), King (150×200 cm) and Super King (180×200 cm). This guide shows each in both inches and centimetres so you can compare across standards.
Is a UK King the same as a US King?
No — they are noticeably different, which is a common and expensive mistake. A US King is 76×80 in (193×203 cm), wider and longer than a UK King at 150×200 cm. A UK Super King (180×200 cm) is closer in width to a US King but still not identical. Because bedding is cut to these standards, sheets and duvet covers do not interchange between the two systems, so always buy bedding in the same standard as the mattress.
How much room do I need around a bed?
A good rule of thumb is about 60 cm (2 ft) of walking space on each side of the bed you use, so you can get in and out, make the bed, and open wardrobe or drawer doors. If the headboard sits against a wall you only need clearance on the two long sides and the foot. Enter your room dimensions above and the guide checks the mattress against the clearance you want and reports what is left on each side.
Are these dimensions exact?
They are the nominal industry sizes, which most manufacturers follow within a couple of centimetres, but real products do vary — and mattress depth (height) varies far more than length or width. Treat these figures as a planning reference, and always confirm the exact dimensions on the manufacturer's specification before buying fitted sheets or a frame that has to match closely.
Nominal sizing reference only. Real mattress dimensions — especially depth — vary by brand and country; confirm with the manufacturer before buying bedding or a frame. Not professional advice.