Door clear opening width
Approved document M, ‘Access to and use of buildings', requires that a minimum clear width is provided by door openings.
According to the approved document, the effective clear width of a door ‘…is the width of the opening measured at right angles to the wall in which the door is situated from the outside of the door stop on the door closing side to any obstruction on the hinge side, whether this be projecting door opening furniture, a weather board, the door or the door stop’
The minimum allowable clear opening widths for dwellings are set out below:
| Doorway clear opening width (mm) | Corridor clear passageway width (mm) |
| 750 or wider | 900 (when approached head on) |
| 750 | 1200 (when approach is not head-on) |
| 775 | 1050 (when approach is not head-on) |
| 800 | 900 (when approach is not head on) |
For buildings other than dwellings, the minimum allowable clear opening widths are:
| Direction and width of approach | New buildings (mm) | Existing buildings (mm) |
| Straight-on | 800 | 750 |
| At right angles to an access route at least 1,500 mm wide | 800 | 750 |
| At right angles to an access route at least 1,200 mm wide | 825 | 775 |
| External doors to buildings used by the general public. | 1000 | 775 |
The clear opening width can be calculated as:
- The width of the door leaf.
- Plus the gap between the leading edge of the door and the frame when the door is closed.
- Minus the width of the door stop at the leading edge of the door.
- Minus the thickness of the door leaf (or the door stop if that is wider).
- Minus the width of any obstructing door furniture (such as the door handle) that projects into the opening when the door is open. If the door opens to more than 90°, door furniture may not obstruct the clear opening width.
Unless a door is powered, there must be a 300 mm nib beyond the leading edge of the door to allow wheelchair users to properly access the handle.
[edit] Find out more
[edit] Related articles on Designing Buildings Wiki
Featured articles and news
Design and construction industry podcasts
Professional development, practice, the pandemic, platforms and podcasts. Have we missed anything?
C20 Society; Buildings at Risk List 2025
10 more buildings published with updates on the past decade of buildings featured.
Boiler Upgrade Scheme and certifications consultation
Summary of government consultation, closing 11 June 2025.
Deputy editor of AT, Tim Fraser, discusses the newly formed society with its current chair, Chris Halligan MCIAT.
Barratt Lo-E passivhaus standard homes planned enmasse
With an initial 728 Lo-E homes across two sites and many more planned for the future.
Government urged to uphold Warm Homes commitment
ECA and industry bodies write to Government concerning its 13.2 billion Warm Homes manifesto commitment.
From project managers to rising stars, sustainability pioneers and more.
Places of Worship in Britain and Ireland, 1929-1990. Book review.
The emancipation of women in art.
Call for independent National Grenfell oversight mechanism
MHCLG share findings of Building Safety Inquiry in letter to Secretary of State and Minister for Building Safety.
The Architectural Technology Awards
AT Awards now open for this the sixth decade of CIAT.
50th Golden anniversary ECA Edmundson awards
Deadline for submissions Friday 30 May 2025.
The benefits of precast, off-site foundation systems
Top ten benefits of this notable innovation.
Encouraging individuals to take action saving water at home, work, and in their communities.
Takes a community to support mental health and wellbeing
The why of becoming a Mental Health Instructor explained.
Mental health awareness week 13-18 May
The theme is communities, they can provide a sense of belonging, safety, support in hard times, and a sense purpose.
Mental health support on the rise but workers still struggling
CIOB Understanding Mental Health in the Built Environment 2025 shows.
Design and construction material libraries
Material, sample, product or detail libraries a key component of any architectural design practice.