Bed Size Calculator · Mattress Fit & Room Clearance

Bed Size Calculator

Find the right mattress size for your room with clearance for walking around

Units
Bedroom dimensions
cm
cm
Measure the two longest walls of the room, floor to floor. Typical bedroom: 300–450 cm each side.
Region & sleepers
1 adult — a mattress at least 100 cm wide is comfortable. Queen or small double works well.
Mattress size
Pick the mattress size you're considering. The calculator checks whether it fits your room and how much walking space you'll have.
Walking clearance
75 cm (30 in) is the standard recommendation for comfortable walking space on at least one side of the bed.
Fit Analysis
✅ Fits Comfortably
Selected mattress
—
—
Bed width
—
Bed length
—
Side clearance
—
Foot clearance
—
Floor area used
—
Free floor area
—
Recommended
—
Room area
—
All sizes for this region
MattressWidth × LengthFits room?Side clearance
Fits assume the headboard sits against a wall and you walk past the foot and the open side(s). If the bed shares a wall on three sides, side clearance may be less important.
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Faiq Ur Rahman

Founder & CEO, Toolraxy

Faiq Ur Rahman is a web designer, digital product developer, and founder of Toolraxy, a growing platform of web-based calculators and utility tools. He specializes in building structured, user-friendly tools focused on health, finance, productivity, and everyday problem-solving.

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A queen bed in a 3 by 3 metre room leaves almost no floor. The same queen in a 5 by 4 metre master looks small. Most bedroom planning tools ignore that balance. This one doesn’t. It runs every mattress size in your region against your actual room dimensions and shows which ones fit, which ones leave comfortable clearance, and which ones would jam you against a wall. The recommended size adjusts for whether you sleep alone, share the bed, or you’re buying for a child. All four regional size standards are covered, and you can work in centimetres or inches.

 

How to Use the Bed Size Calculator

  1. Choose Metric or Imperial from the toggle at the top.

  2. Enter your room length and room width.

  3. Pick your region to load the standard mattress sizes.

  4. Select your sleeper count: kids, one adult, or two adults.

  5. Choose the mattress size you’re considering.

  6. Set your preferred clearance around the bed.

  7. Check the fit verdict in the results panel.

  8. Scroll to the size table to see every regional mattress compared against your room.

 

How the Bed Size Calculator Formula Works

The tool tries the mattress in both orientations and picks whichever leaves more walking space.

Formula: Fits? (orientation A) = bed length ≤ room length AND bed width ≤ room width
Formula: Fits? (orientation B) = bed length ≤ room width AND bed width ≤ room length
Formula: Side clearance = (room dimension across the bed − bed width) ÷ 2
Formula: Foot clearance = room length − bed length
Formula: Floor area used = bed width × bed length
Formula: Free floor area = room area − bed area

Room dimensions convert to centimetres first, no matter which unit you entered. The tool then checks both orientations. If both fit, it picks the one with more side clearance. If only one fits, it uses that one.

Clearance thresholds decide the verdict. Below 45 cm of side space, the fit is flagged as very tight. Below your preferred clearance, it’s flagged as tight. Above your preferred clearance, it’s comfortable. A separate check finds the smallest mattress that fits the room at or above the minimum width for your sleeper count: 75 cm for kids, 100 cm for a single adult, 145 cm for two adults.

Validation requires positive room dimensions. Blank fields trigger an invalid input message instead of a nonsense result.

 

Worked Example

A typical UK bedroom measures 380 cm by 340 cm. The owner wants a king-size mattress for two adults and prefers 75 cm of walking clearance.

King size (UK): 150 cm wide by 200 cm long.

Orientation A: 200 ≤ 380 (yes), 150 ≤ 340 (yes). Fits.
Side clearance: (340 − 150) ÷ 2 = 95 cm
Foot clearance: 380 − 200 = 180 cm

Orientation B: 200 ≤ 340 (yes), 150 ≤ 380 (yes). Fits.
Side clearance: (380 − 150) ÷ 2 = 115 cm
Foot clearance: 340 − 200 = 140 cm

Orientation B gives more side clearance, so the calculator picks it.

Floor area used: 150 × 200 = 30,000 cm², or 3.0 m²
Room area: 380 × 340 = 129,200 cm², or 12.92 m²
Free floor area: 9.92 m²

The badge reads “Fits Comfortably” because 115 cm exceeds the 75 cm target. The recommended size for two adults in this room lands on the king, since it’s the smallest that fits at or above 145 cm width. A super king would also fit, with 80 cm of side clearance in orientation B.

What Bed Size Do I Need for My Room?

A queen mattress (152 × 203 cm) needs a room at least 270 cm by 320 cm to sit comfortably with 75 cm of clearance on the sides and at the foot. A king (193 × 203 cm) pushes that to 320 cm by 350 cm. A double (137 × 190 cm) fits in rooms as small as 250 cm by 290 cm. Work backwards from your room: measure the wall the headboard will sit against, subtract the mattress length, and check what’s left at the foot.

 

How Do You Measure a Room for a Bed?

Measure the longest wall and the shortest wall, floor to floor. Take the measurements at the skirting board, not at the ceiling, because walls rarely sit plumb. Note the position of doors, windows, and radiators before deciding where the bed goes. You want at least 60 cm of clearance on the open side of the bed and 75 cm of walking space at the foot. The calculator assumes the headboard sits flush against a wall.

 

What Is the Standard Size of a Double Bed?

A UK double mattress measures 135 × 190 cm. In US sizing, the equivalent “Full” is 137 × 190.5 cm. European doubles run 140 × 200 cm. Australian doubles sit at 138 × 188 cm. The differences are small in width but up to 10 cm in length, which matters for taller sleepers. Two adults on a double have about 67 cm of personal space each, which most find cramped.

 

What Is a Queen Size Bed in cm?

A US Queen measures 152.5 cm wide by 203 cm long. A UK King is similar at 150 × 200 cm. A European Queen sits at 160 × 200 cm. An Australian Queen is 153 × 203 cm. Despite the different names, these all fall within a narrow band. The US Queen and AU Queen are nearly identical. The EU Queen is 7 to 10 cm wider.

 

How Much Space Should You Leave Around a Bed?

You want at least 60 cm of clearance on any side you need to walk past. Seventy-five centimetres is the comfortable standard. Ninety centimetres allows for furniture like a bedside table without crowding the walkway. Leave 60 to 75 cm at the foot of the bed for pulling back sheets and getting in. If the bed sits in a corner with the wall on two sides, you only need clearance on the open side and at the foot.

 

What Size Bed Fits in a 3 by 3 Metre Room?

A 3 by 3 metre room has 9 square metres of floor. A double bed takes up 2.56 m². A queen takes 3.1 m². A king takes 3.9 m². A double bed in a 3 by 3 room leaves 45 cm of clearance on the sides if the bed sits widthways, which is tight. A single bed at 90 × 190 cm leaves 105 cm on each side. A small double at 120 × 190 cm gives 90 cm of side clearance and still fits two adults snugly.

 

Is a King Size Bed Too Big for My Room?

It’s too big if the room is under 3.2 metres in either direction. A king (193 × 203 cm) needs at least 320 cm across the width and 350 cm along the length for comfortable walking space. In smaller rooms, a queen or double leaves more floor. The calculator flags a king as “Tight” or “Doesn’t Fit” once side clearance drops below 45 cm or the mattress won’t physically fit.

 

Which Way Should a Bed Face in a Room?

The headboard goes against the longest wall. That gives the most room at the foot of the bed for walking. If the longest wall has a window, pick the next-best option or use a low-profile headboard. Avoid placing the bed directly under a window in cold climates. If the room has a door that opens inward, leave clearance so the door doesn’t hit the bedframe.

 

How Do You Share a Bed Comfortably?

At 145 cm wide, two adults have about 72 cm of personal space each. That’s the comfortable minimum. A queen at 152 cm gives 76 cm each. A king at 193 cm gives 96 cm each, which is where most couples stop feeling crowded. Couples who move a lot in their sleep or have different sleep temperatures usually find a king worth the extra floor space.

 

Common Mistakes When Sizing a Bed for a Room

Forgetting the bedframe adds width and length beyond the mattress dimensions. A king mattress in a wide frame can be 10 to 15 cm larger in each direction. Ignoring the headboard is a similar trap. Headboards add 5 to 10 cm of depth. Forgetting bedside tables means the mattress fits but the room still feels crowded once you add furniture. And never trust the room measurements from a floor plan. Measure with a tape before buying.

 

When Should You Consider a Custom Mattress?

Custom sizes make sense for antique bedframes, boats, campervans, and rooms with unusual shapes. Most manufacturers offer custom sizes at a 30 to 50 percent premium over standard. The trade-off: custom sheets cost more and take longer to arrive. Before going custom, check whether a standard size from a different region (EU 160 × 200 instead of a UK King) fits your frame without the premium.

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