Measurements in, bounded arithmetic out.

What the tools do

• Fit checking compares all allowed three-axis orientations against a measured clear opening.
• Allocation uses material thickness, compatible clear height/depth, shelf count and an editable working-fill percentage.
• Headroom divides usable run by average thickness, then compares normal and full-return counts.

How mixed-format allocation works

Enter 1–12 material groups and 1–12 bay profiles. All shelves within one profile share the same usable width, clear height and depth; use separate profiles for different dimensions. Each profile supports 1–1,000 shelves. The same target-fill percentage applies to every shelf.

1. Each shelf starts with a working run of usable width × target fill ÷ 100.
2. Groups are processed in the displayed order. For each group, the planner visits bay profiles in their displayed order and then each shelf in that profile.
3. An upright item requires enough clear height and depth. Its thickness must fit entirely within one shelf's remaining working run. Whole-item capacity is rounded down on each shelf separately; leftover fragments from separate shelves are never joined.
4. Placed items reduce the space available to later groups. The result lists every group's requested, placed and unplaced counts, plus every bay's remaining working run.

This is sequential first-fit, not global optimization. It does not automatically reorder or rotate groups, reserve a particular bay for a later group, or search for a best arrangement. Use “Move earlier” to compare entry orders. A shortfall means this ordered attempt left items unplaced, not that every possible arrangement would fail.

Remaining bay run is the sum of per-shelf fragments; a positive total does not guarantee that another whole item fits. “Working run used” measures the share of the target-fill allowance consumed, not the share of the bay's full physical width. Displayed run lengths are rounded to 0.1 cm.

Every item in a group is modelled using the same entered measurements. Average thickness can hide individual variation, so check representative items and real clearances before moving a collection. Blank fields are rejected, not interpreted as zero.

What they do not do

• No structural load, seismic, fire-code, accessibility, preservation or ergonomic compliance advice.
• No inferred vendor dimensions, collection catalog, barcode, title or patron records.
• No guarantee that annual additions, circulation or processing rates remain constant.