Know when a rectangular comparison is insufficient.
Reviewed by the operator 2026-09-07
Under the sink
Diagram: plumbing can interrupt a rectangular footprint.
Record the cabinet opening, the usable interior and the position of pipes. The empty space beside the plumbing is different from the full cabinet volume.
A mounted pull-out also needs a model-specific check for its mounting points and travel. The drawer checker is not designed to approve an under-sink installation.
What the size check can and cannot do here.
The dimension check on this site compares one freestanding tray with a rectangular space. It does not model pipes, hinges or mounted pull-outs. When those details are unknown, the honest answer is “more measurements needed.”
Record an actual clear space rather than the entire cabinet exterior. A pipe, trap, hinge or disposal may occupy the part of the cabinet where a proposed shelf needs to sit or move.
Do not approve installation from three numbers
This site does not create a 3D map of plumbing. When obstructions or mounting details remain unknown, its result stays “more measurements needed.” It does not recommend moving plumbing or drilling the cabinet.
Check the manufacturer’s opening requirements
For a specific mounted unit, gather its installation instructions and exact cabinet-opening requirements. Product width alone may not be the correct measurement to compare.
Example source lead: Rev-A-Shelf 4SBSU series. Series-level information must be narrowed to the exact model before a recommendation.
No product has been tested or recommended in these notes.