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Corridor Width Calculator - Part M Wheelchair Access & Passing Places

Calculate corridor widths for wheelchair access and passing places per Approved Document M and BS 8300.

Total length of the corridor

People using the corridor as an escape route. Part M widths do not scale with this, but it prompts a separate AD B escape-width check above ~60 people.

Wheelchair Passing Required

Whether two wheelchairs need to pass each other

How We Calculate This

This calculator determines the required corridor width, whether passing places are needed, and the overall corridor area, based on Approved Document M and BS 8300-2:2018.

Width standards (buildings other than dwellings)

  • 1200mm: AD M Vol 2 minimum unobstructed corridor width (para 3.14b)
  • 1800mm: width that lets two wheelchairs pass without passing places (para 1.11); below this, passing places are required
  • 2000mm+: a design recommendation for busy public buildings, not a Part M minimum

In dwellings (AD M Vol 1) the minimum clear width of every hall or landing is 900mm for an M4(2) home (750mm at a localised obstruction). M4(3) wheelchair-user homes have a higher minimum (para 3.24): every hallway, approach or landing must be at least 1050mm wide, rising to 1200mm where a door is not approached head-on.

Passing places

In a building other than a dwelling, where a corridor is narrower than 1800mm and wheelchair passing is needed, passing places of at least 1800mm × 1800mm are required (AD M Vol 2 para 3.14c). AD M does not give a fixed spacing — it requires them "at reasonable intervals, e.g. at corridor junctions", positioned within sight of one another. Dwellings do not use 1800mm × 1800mm passing places.

Effective width

The effective clear width is the structural width minus any projections such as handrails, radiators or fire equipment. Enter your actual proposed width to test it against the minimum and check whether passing places are needed.

Frequently Asked Questions

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Last updated: March 2026

Verified against UK standards · estimates only, confirm with your supplier.