SettingsSettings for this calculationUS
Which document's minimum the width is set beside.
The two measure the same opening differently and set different minimums, so the result is only meaningful against the one that applies to the building.
A deep opening is harder to steer through, so the ADA asks more of it.
A doorway through a thick wall, or a short passage, more than 24 in (610 mm) deep must be at least 36 in (915 mm) clear rather than 32 in (815 mm).
The clear opening, measured the way the chosen rule measures it.
Approved Document M: at right angles to the wall, from the door stop on the closing side to whatever projects furthest on the hinge side — the door itself, its handle or a weather board. ADA: between the face of the door and the stop, with the door open 90 degrees. Neither is the door leaf's width.
Measured width as a share of the minimum
103 %
The measured width is 103% of the minimum the 2010 ADA Standards give a door opening. A width at or over the minimum is not a finding that the doorway is usable: the space to approach it, the clear space beside the leading edge, the force needed to open it and the threshold each have their own requirement.
- Minimum effective clear width for this door
- 32 in
- Measured clear width
- 33 in
- Room to spare over the minimum
- 1 in
They open the calculator with your figures already in it
Door Effective Clear Width Calculator (Approved Document M and ADA): 103 % — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- Approved Document M Volume 2, Table 2, Minimum effective clear widths of doors (new / existing buildings): straight-on 800 / 750 mm; at right angles to an access route at least 1500 mm wide 800 / 750 mm; at right angles to an access route at least 1200 mm wide 825 / 775 mm; external doors to buildings used by the general public 1000 / 775 mm — measured at right angles to the wall from the outside of the door stop on the closing side to any obstruction on the hinge side (Diagram 9)
- 2010 ADA Standards for Accessible Design, 404.2.3: door openings shall provide a clear width of 32 inches (815 mm) minimum, measured between the face of the door and the stop with the door open 90 degrees; openings more than 24 inches (610 mm) deep shall provide 36 inches (915 mm) minimum
Inputs used
- Rule to Compare Against
- 2010 ADA Standards (United States)
- Building
- New building
- How the Door Is Approached
- Straight on, with no turn
- Depth of the Opening
- 24 in (610 mm) deep or less
- Measured Clear Width
- 33 in
Intermediate steps
- Minimum effective clear width for this door
- 32 in
- Measured clear width
- 33 in
- Room to spare over the minimum
- 1 in
Confidence note: The measured width is 103% of the minimum the 2010 ADA Standards give a door opening. A width at or over the minimum is not a finding that the doorway is usable: the space to approach it, the clear space beside the leading edge, the force needed to open it and the threshold each have their own requirement.
What this calculation does not cover
- It compares one measurement with one minimum. Whether the door is measured the way the rule measures it — past the handle, the weather board and the stop — decides whether the comparison means anything.
- The two rules measure differently: Approved Document M from the stop on the closing side to the furthest projection on the hinge side, the ADA from the face of the open door to the stop. A reading taken one way does not transfer to the other.
- Approved Document M's opening-force limits, the manoeuvring space beside the door and the threshold are separate requirements; the ADA's manoeuvring clearances have their own calculator on this site.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-22 · v1.0.0
Regulatory standards & verification citations2
- Approved Document M Volume 2, Table 2, Minimum effective clear widths of doors (new / existing buildings): straight-on 800 / 750 mm; at right angles to an access route at least 1500 mm wide 800 / 750 mm; at right angles to an access route at least 1200 mm wide 825 / 775 mm; external doors to buildings used by the general public 1000 / 775 mm — measured at right angles to the wall from the outside of the door stop on the closing side to any obstruction on the hinge side (Diagram 9)
- 2010 ADA Standards for Accessible Design, 404.2.3: door openings shall provide a clear width of 32 inches (815 mm) minimum, measured between the face of the door and the stop with the door open 90 degrees; openings more than 24 inches (610 mm) deep shall provide 36 inches (915 mm) minimum
Which documents these citations point at
- Approved Documents to the Building Regulations (England) — M (United Kingdom)Practical guidance on meeting the Building Regulations, one lettered part per subject — Part A structure, Part B fire, Part K protection from falling, Part L conservation of fuel and power, and the rest.
A code or standard has force only where a jurisdiction has adopted it, usually with local amendments. This site holds no adoption data for any authority, so check what is in force with the authority where you build. Any section cited above without an edition should be checked against the edition in force where you build. What it would take to know.
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