Clear door opening width: what a compliant block needs

The number that actually matters isn't the door size

I've had this conversation with junior drafters more times than I can count, and it always starts the same way: someone specifies a 900mm door on a schedule and assumes the job is done, and it isn't, because the door leaf size and the clear opening width are two different numbers. Clear opening width is what's left after you subtract the frame, the stop, and the swing of the door itself when it's open at ninety degrees, and that's the number a wheelchair, a walker, or a person carrying a box actually has to pass through.

So when you're checking a door against accessibility requirements, the door schedule dimension is only a starting point. A 900mm door leaf typically nets somewhere in the 800 to 850mm range of actual clear opening once you account for a standard frame and stop, and that's usually enough to clear most accessible thresholds, but it's tight, and it's exactly the kind of tight that gets flagged in a review if the hinge hardware or door closer arm eats into it further.

The range drafters actually work to

Every accessibility code phrases this a little differently, and this is genuinely one of those areas where you should always confirm against the specific code governing your project rather than trust a rule of thumb, but the ranges cluster in a fairly predictable band. In the US, the ADA typically calls for a minimum clear opening around 32 inches (roughly 815mm), measured with the door open 90 degrees, from the face of the door to the opposite stop. UK and similar Part M style guidance usually lands in a comparable 775 to 850mm range depending on the approach and whether it's a straight-on or angled approach to the door.

What I actually do when I'm laying out a building with mixed accessible and standard doors is set a minimum clear opening target early, usually 850mm as a safe round number that clears most codes with margin, and then work backward to the door leaf size I need to specify, rather than starting from a standard door size and hoping the clear opening survives. It's a small habit but it saves a lot of late-stage door schedule rework.

Double doors complicate this further, because on a pair of doors only the active leaf, the one that opens under normal use, typically needs to meet the clear opening minimum on its own, and codes usually don't let you add both leaves together to hit the target width unless the inactive leaf is set up to open automatically alongside it. I've seen door schedules pass a quick glance because the combined opening of both leaves looked generous, only to fail review because the active leaf alone was 700mm, well under any reasonable accessible minimum.

What a wheelchair CAD block actually shows you

This is where a good accessibility block earns its keep. The wheel-chair-accessible blocks on this site are drawn in plan view with the wheelchair footprint at a realistic real-world scale, so once you drop one into your drawing at 1:1 units, you get an honest visual reference for how much room a chair actually needs relative to the opening you've drawn. It's not a substitute for running the numbers, but it catches the mistakes the numbers alone don't, like a door that technically clears code on paper but reads as obviously too tight the moment you see a figure sitting next to it.

Pairing the wheelchair block with one of the human-figure-disable blocks in the same scene is something I do on almost every accessible layout, because reviewers and clients respond to seeing a figure in the doorway far more than they respond to a dimension string, even when the dimension string is the thing that's actually being checked.

How I check it in AutoCAD

Once the door is drawn, I use DIST (or the equivalent measure tool) to check the actual clear opening path, not the door leaf, and I do it with the door swung open in the drawing rather than trusting the schedule. Then I insert the wheelchair block at the door location, scaled 1:1 to match my drawing units, and rotate it to face the direction of travel through the opening. If there's any visual overlap between the chair's footprint and the door stop, frame, or hardware, that's a flag before it ever gets to a site walk.

For doors on an accessible route specifically, I also check the approach clearance on both sides, not just the opening itself, because a compliant clear width means very little if there isn't enough level floor space in front of the door for a wheelchair to actually maneuver into position to open it.

Where drafters lose the width without noticing

The most common pitfall by far is hardware. A lever handle, a push plate, a door closer arm, or a kick plate can all project into the clear opening by 25 to 50mm, and if your clear width was already at the minimum, that hardware alone can push you out of compliance. The second most common is the door stop detail, especially on fire-rated doors where the stop is deeper than a standard residential detail. The third is threshold height, which isn't a width issue exactly but trips up the same doors, since accessible thresholds are usually capped at a low maximum height, often in the range of 13mm or less, to avoid becoming a trip hazard or wheel-catch.

None of these show up if you're only checking the door schedule number against a code minimum. They only show up when you actually draw the swing, the hardware, and a figure passing through, which is exactly why the block-based check matters as much as the dimension check.

Finding the right blocks on the site

You'll find the wheelchair and human figure blocks under the building-symbols category on this site, and they're free DWG downloads with no signup required, same as everything else in the library. Both come ready to drop into a plan view at real-world scale, so there's no rework needed to get them reading correctly next to a door you've drawn. If you're setting up a full door schedule, it's also worth browsing the doors category, since having a range of door block widths on hand makes it faster to test a few leaf sizes against your target clear opening before you commit to a schedule.

A quick way to sanity check a whole door schedule

When I'm working through a full door schedule rather than a single opening, I add two extra columns next to the standard leaf-size column, one for calculated clear opening and one for a pass or fail against my target figure, and I fill both in before the schedule goes out for review rather than after. It takes maybe twenty minutes on a typical schedule of thirty or forty doors, and it turns a coordination problem that would otherwise surface late, usually during a formal accessibility review, into something caught and fixed while the drawing is still easy to change. Doors on an accessible route, doors into accessible bathrooms, and doors into any space required to be accessible are the ones I check first, since those are the openings a reviewer will focus on regardless of how the rest of the schedule reads.