What is the minimum door width for wheelchair access in the UK?

Approved Document M requires a minimum effective clear width of 800mm for new buildings. This is the usable opening width when the door is open 90 degrees, not the door leaf size. A standard 926mm (3'0") door leaf typically gives approximately 879mm effective clear width, which is compliant. For existing buildings, a minimum of 750mm effective clear width may be acceptable as a reasonable provision.

What is the difference between door leaf width and effective clear width?

The door leaf width is the full width of the door panel. The effective clear width is the actual usable opening that a wheelchair can pass through when the door is open 90 degrees. Deductions from the leaf width include the door stop (25-30mm), ironmongery projections (handles, hinges), and the door thickness when open at 90 degrees. A 926mm leaf typically gives around 879mm effective clear width.

What is a nib and why is it needed?

A nib is the wall space between the door frame and any adjacent wall on the leading (pull) side of the door. Part M requires a minimum 300mm nib on the pull side when the door is approached from the side. This allows a wheelchair user to position themselves alongside the door to reach and operate the handle without being blocked by the door swing.

What threshold height is permitted for accessible doors?

Part M and BS 8300 recommend level thresholds wherever possible. Where a threshold is unavoidable, the maximum height is 13mm (15mm with a chamfered or pencil-round profile). For external doors, a maximum 15mm upstand with a weatherbar is generally accepted. Any higher threshold creates a trip hazard and a barrier for wheelchair users.

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Door Width Calculator - Part M Effective Clear Width

Calculate effective clear door widths for wheelchair access per Approved Document M and BS 8300.

Door Leaf Width

Width of the door leaf (panel), not the opening

Door TypeSingle leaf, double (pair), or sliding door

Approach DirectionHead-on or side approach affects nib requirements

Wall Thickness

Structural wall thickness at the door opening

How We Calculate This

This calculator determines the effective clear width of a door opening and checks compliance with Approved Document M (Access to and use of buildings) and BS 8300:2018.

Effective clear width calculation

For a single hinged door: Effective Clear Width = Leaf Width - Door Stop - Ironmongery Projection. The door stop is typically 25-30mm. Ironmongery (handles, locks) may project 15-25mm from the door face.