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Corridor Width Calculator

Measure the corridor wall to wall and list what sticks out from each wall; the corridor width calculator gives the clear width that is left. Then check a piece of furniture against an L-shaped turn: the calculator finds the longest item of that depth that can be carried round the corner flat.

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Corridor width calculator

Planning aid, not a building-code check. Requirements vary by jurisdiction and building type. Confirm with your local rules or a qualified professional. Escape-route and accessibility widths are not checked. The corner check is plan view only: the item is carried flat at its full depth; tilting or standing it on end can let longer items through, so a “no” here is conservative.

Bare numbers are meters; 190 mm works too.

Things that stick out from the walls

 

 

 

 

 

 

Assumptions

Change any value to match your product or local rules.

 

Basis: Required widths differ by jurisdiction and building type; enter yours

Clear width
0.85 m
2′ 9″
Against your target
No target entered
Longest item that turns the corner flat
1.23 m
4′
Tightest angle in the turn
45.0°
Does your item turn flat?
No, 0.67 m too long to turn flat

Clear width 0.85 m (2′ 9″). Carried flat, an item 0.80 m (2′ 7″) deep turns this corner if it is at most 1.23 m (4′) long.

1.00 m1.00 m
How this was calculated
  • Clear width = wall-to-wall − deepest projection on the left − deepest projection on the right
  • Longest item = minimum over θ of a ÷ sin θ + b ÷ cos θ − depth ÷ (sin θ × cos θ), checked every 0.01°
  1. Clear width = 1.00 m − 0.10 m − 0.05 m = 0.85 m
  2. Longest item = 1.00 m ÷ sin 45.00° + 1.00 m ÷ cos 45.00° − 0.80 m ÷ (sin × cos) = 1.23 m

How it works

  1. Wall to wall

    Measure between the finished wall faces at the narrowest point you care about.

  2. Subtract projections

    Radiators, handrails, skirting and shelving each take a bite. On each side only the deepest one counts, since they sit at different points along the wall.

  3. Compare with your target

    Enter the clear width you need, from your rules or your own requirement, to see the margin either way.

  4. Check the corner

    For a right-angled turn, the calculator tries every angle in 0.01° steps and finds where the item would jam.

Worked example

A corridor 1000 mm wall to wall with a 100 mm radiator on the left and a 50 mm handrail on the right has 1000 − 100 − 50 = 850 mm clear.

At a corner between two corridors 1000 mm wide, an item 800 mm deep jams at 45°, where the longest item that turns flat is about 1228 mm. A 1.9 m sofa of that depth will not go round flat. Make the second corridor 1200 mm wide and the limit rises to about 1497 mm, now at about 39.3°. In imperial, two 40 in corridors and a 32 in deep item give a limit of about 49.1 in.

Wall-to-wall width vs clear width

Wall-to-wall width is what the plan shows between wall faces. Clear width is what is left for people and furniture once fixed items are subtracted. Measure the items you have rather than guessing their depth.

This version takes the deepest projection on each side and subtracts both, which is the narrowest point if they line up across the corridor. If they are far apart along the corridor, check each stretch on its own.

Doors that open into a corridor

A door swinging into a corridor takes up to its full leaf width of clear width while it is open, and two doors facing each other can meet. Check those spots with the door clearance calculator, which gives the swing depth and where an obstacle stops the leaf.

Getting furniture round a corner

The corner check treats the item as a rectangle seen from above, carried flat at its full depth. As it turns, its inner edge pivots on the inside corner while its outer corners sweep toward the outside walls; the length that fits at the tightest angle is the limit shown.

A “no” is conservative. Tilting a sofa up on its end, lifting it over a low handrail, or removing its legs or cushions can all get a longer item through. Measure the depth of the item without anything that comes off.

Frequently asked questions

How do I measure corridor clear width?

Measure wall face to wall face, then subtract anything fixed that sticks out: radiators, handrails, skirting, shelving or pipe boxing. Use the deepest item on each side if they line up across the corridor.

Do handrails reduce corridor width?

Yes, by their projection from the wall, measured to the outer face of the rail. Whether your rules count that reduction depends on the rules, so check how they define clear width.

Will my sofa fit around the corner?

Enter the clear width of the corridor before and after the turn, and the sofa’s depth and length. If its length is at most the limit shown, it turns carried flat. If not, it may still go through tilted or on end.

Why does tilting help?

Standing a sofa on its end or tipping it lets part of it pass above the narrow plan corner, so the plan-view limit no longer applies. The calculator models the flat case alone, which makes its “no” a cautious answer.

How wide should a hallway be?

That depends on the building’s rules and on how the corridor is used, so this page does not suggest a figure. Enter the width you need as the target and the calculator shows the margin.

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