Bed Size Calculator

The short answer

Start from the frame, not the mattress. A frame adds about 5 in to the mattress each way. Then leave about 24 in of walkway on each side you use and at the foot. With that, a queen (60 × 80 in) fits a room from 10 × 10 ft, a king (76 × 80 in) from 11 × 10 ft and a twin (38 × 75 in) from 8 × 9 ft.

A king or a California king is more comfortable in a room of 12 × 12 ft, which leaves space for nightstands and a dresser too.

How to measure

1. The room: measure the width and length wall to wall, or to furniture that stays, like a built-in.
2. Your frame: if you already have a bed, measure its outside width and length, headboard and footboard included. A frame is larger than its mattress.
3. Doors and drawers: note where the room door swings, where the closet opens and where a dresser stands, so the bed doesn’t block them.

Before you buy, mark the bed’s outline on the floor with painter’s tape and walk around it.

How to use the calculator

1. Enter the room’s width and length. Room sizes carry over from the other bedroom calculators.
2. Choose where the bed goes: centered on a wall, with a walkway on both sides, or against a side wall, with one.
3. Choose the frame: a standard frame, or a big headboard, footboard or upholstered bed.
4. Check the box for a dresser facing the foot of the bed.
5. Read the result: the largest bed that fits, a plan from above and every standard size, each labeled Fits, Tight or Doesn’t fit with the walkways it leaves. Copy link keeps your numbers in the address, and the next step takes the bed on to the comforter calculator.

How we calculate

The walkways below leave room to walk around the bed and to make it. If your bed is already in the room, its own frame size comes first.

• The frame: the mattress plus 5 in each way, as much as a standard frame adds, or plus 10 in for a big headboard, a footboard or an upholstered bed.
• The walkways: at least 24 in on each open side and at the foot Fits. 18 in to 24 in is Tight, a squeeze you can still walk through. Less doesn’t fit. 36 in or more all around reads as room to spare.
• The headboard wall: the headboard needs nothing behind it. The calculator tries it on each wall and keeps the one that leaves more walkway.
• Against a side wall: one open side instead of two.
• A dresser at the foot: 18 in deep, a typical depth, with 36 in in front of it to Fit, so you can walk by and open the drawers, and 24 in Tight.
• The pick: the largest mattress that Fits, or if none does, the largest that’s Tight.

Nightstands, the door’s swing and the closet aren’t in the math. The result lists them as notes.

Worked examples

Worked example

A 10 × 10 ft bedroom

What we know

• Room: 10 × 10 ft
• Bed: centered on a wall, standard frame

How it works out

1. Queen: a 65 × 85 in frame leaves 27.5 in on each side and 35 in at the foot: Fits.
2. California king: a 77 × 89 in frame leaves 21.5 in on each side and 31 in at the foot: Tight.

A queen bed, with 27.5 in on each side and 35 in at the foot.

Worked example

A 7 × 10 ft room with the bed against a side wall

What we know

• Room: 7 × 10 ft
• Bed: against a side wall, standard frame

How it works out

1. Full: a 59 × 80 in frame leaves 25 in on the open side and 40 in at the foot: Fits.
2. Queen: a 65 × 85 in frame leaves 19 in on the open side and 35 in at the foot: Tight.

A full bed, with 25 in on the open side and 40 in at the foot.

Worked example

A 12 × 12 ft room with a dresser and an upholstered bed

What we know

• Room: 12 × 12 ft
• Bed: centered on a wall, big headboard or upholstered frame, a dresser at the foot

How it works out

1. King: an 86 × 90 in frame leaves 29 in on each side and 36 in in front of the dresser: Fits.

A king bed, with 29 in on each side and 36 in in front of the dresser.

Room size for each bed

The smallest room each bed Fits, centered on a wall with a standard frame, next to a more comfortable room with space for nightstands and a dresser. For a full, that room runs from 9 × 10 to 11 × 11 ft.

At a squeeze, against a wall or with a dresser

The same beds at the Tight walkways, against a side wall, and with a dresser facing the foot. No room in these tables is smaller than the building code’s minimum for a bedroom, 70 sq ft and 7 ft each way.

Standard mattress sizes

• Twin: 38 × 75 in, for one sleeper, and the usual first bed after a crib.
• Twin XL: 38 × 80 in, for one tall sleeper or a growing teen.
• Full: 54 × 75 in. Shared, it leaves each person 27 in.
• Queen: 60 × 80 in, 30 in each for two.
• King: 76 × 80 in, 38 in each, as much as a twin.
• California king: 72 × 84 in, longer and narrower than a king, with 36 in each, and the better fit for a narrow room.

A few brands make a full a little narrower or a twin a little wider, but the difference is small. The calculator uses the standard sizes above.

Nightstands, doors and closets

• Nightstands: a standard one is about 18 in wide, set 2 to 6 in from the bed. In a tight room, look for nightstands 10 to 15 in wide, or use one nightstand and a wall shelf. The nightstand height calculator sizes them for your bed.
• Doors: keep the door’s swing clear and about 3 ft of floor from the doorway to the nearest furniture.
• Closets and drawers: leave a hinged closet door room to open fully, and room for a storage bed’s drawers to slide all the way out.

Before you buy

Once the size is settled, find the comforter size for the mattress, the headboard size for the wall behind it and the rug size for the floor under it. Each takes the room and the bed from this calculator.