A to Z

The defined vocabulary.

This is the working vocabulary behind every ItemFits verdict. Each term names a specific quantity the solver actually computes, like the clear opening of a door, the diagonal an item can use when tilted, or the headroom above a staircase. The definitions are plain language, the math is shown where it applies, and every published number carries its source so you can check it.

ADA door minimum widthThe accessibility standard requiring at least 32 inches of clear opening width at a doorway measured with the door open 90 degrees.Clear opening widthThe actual unobstructed horizontal gap of a doorway measured between the face of the open door and the opposite stop, which is always narrower than the nominal door size.Diagonal clearanceThe largest straight-line distance an object can occupy while passing through an opening when tilted corner-to-corner, equal to the square root of the opening width squared plus height squared.Elevator car dimensionsThe interior width, depth, and height of an elevator cab, which together cap the largest rigid item that can stand or lean inside it.Elevator door openingThe clear width and height of an elevator’s entrance, often narrower than the cab interior and frequently the dimension that actually blocks a large item.Measurement toleranceThe small slack ItemFits holds around every verdict to absorb tape-measure error and real-world variation, so a fit that is closer than the band is reported as tight rather than certain.Orientation (W×D×H)Which of an item’s three dimensions, width, depth, and height, is aligned with each axis of an opening as the item is rotated to find a pose that passes.Stair headroomThe vertical clearance measured plumb from a stair’s nosing line to the ceiling or soffit above, which residential code sets at a minimum of 6 feet 8 inches.Swing clearanceThe floor space a door’s arc and an approaching person need on the latch and hinge sides so the door can open fully without the opening being pinched by its own leaf.Tilt angleThe angle from vertical at which an oversized item must be leaned so that its profile fits inside an opening it cannot clear standing upright.Turning radiusThe space a rigid item needs to swing around a corner, set by its longest straight span sweeping through the bend rather than by its width alone.Winder turnA staircase turn made with wedge-shaped treads instead of a flat landing, which narrows the usable carrying path on the inside of the bend.

Why it matters

Words behind the verdict.

ItemFits answers will it fit with real geometry, not a guess. A door is not just its nominal size, a hallway turn is decided by an item's diagonal rather than its width, and a tight pass depends on which face leads. Each term here is one of those quantities, defined once and used the same way on every fit check, so a verdict always means exactly the same thing. Where a standard sets a real number, such as an accessibility minimum or a building code, we cite it; where a number comes from our own geometry, we say so.

Run a check

Put the vocabulary to work.

Doorway fitWill it clear the door, frame, and stops?Stair fitWill it make the turn at the landing?Vehicle fitWill it load into the trunk or cargo area?Elevator fitWill it fit the car and the door opening?Hallway fitWill it pass down a tight corridor?Window fitWill it hoist through the sash opening?Answered fit questionsSee these terms in real, validated fit checks.

Spatial-Fit Glossary

The defined vocabulary.

Words behind the verdict.

Put the vocabulary to work.

Will it fit? Check before you commit.

Spatial-Fit Glossary

The defined vocabulary.

Words behind the verdict.

Put the vocabulary to work.

Will it fit? Check before you commit.