Tell us how tall you are, how you sleep and who shares the bed, and get a mattress size that actually fits — with room left to walk around it.
Bed Size Calculator
How this calculator works
The calculator starts from the tallest sleeper: your mattress should be at least eight inches longer than you are, so your feet and pillow both fit. It adds width for your sleeping position — sprawlers need more room than side sleepers — and for a partner, children or pets. It then picks the smallest standard size that covers both, and reminds you to leave walking space around the bed.
Good to know
Common US sizes are Twin 38×75 in, Twin XL 38×80 in, Full 54×75 in, Queen 60×80 in and King 76×80 in. Measure your room and bed frame before ordering, as headboards and storage drawers need extra depth beyond the mattress itself.
Leave about 24 to 30 inches to walk at the sides and foot where you can, and 36 inches for drawers or doors to open. In a tight room, sizing down one step, choosing a low frame or skipping bulky footboards keeps the room usable even if the mattress is slightly smaller.
Frequently asked questions
How much space should I leave around the bed?
Aim for roughly 24-30 inches of clear floor on each side you use and at the foot, with about 36 inches where wardrobes or drawers open. If that leaves the room cramped, a smaller frame or lower headboard helps more than squeezing the walkways.
When should I size down?
Queen vs King – which fits a 10×12 room?
A Queen usually fits a 10×12 bedroom more comfortably, leaving room for nightstands and walking space. A King can fit on paper but often crowds doors and dressers, so choose it only if you can keep clear paths and do not need large extra furniture.
What if the tallest sleeper is over 6 feet?
Choose an 80-inch length such as Twin XL, Queen or King so feet do not hang off the edge. Add roughly eight inches to the tallest sleeper height as a simple comfort check before you buy.
When should I size down?
Size down when the larger mattress would block doors, leave less than about 20 inches to squeeze past, or crowd out needed storage. A slightly smaller bed with clear walking space usually feels bigger day to day.