Layout model and usable dimensions
Equal shelf spacing must account for the thickness of each shelf as well as the objects you want to store. This calculator shares the available inside height across the openings above, between, and below a chosen number of shelves. Fixed margins let you reserve space for hardware or a raised base. It returns the clear opening height and a list of shelf-bottom elevations measured from the cabinet’s inside bottom. Use the result for a layout drawing, then check the actual storage items, shelf supports, and load requirements before drilling holes or cutting parts.
Fit, direction and offcut constraints
- Shelf support holes may sit below the reported shelf bottom by the support hardware’s own offset.
- Equal openings are a design choice; tall items may justify uneven spacing or adjustable shelf positions.
- The calculator does not determine safe shelf span, material thickness, or allowable load.
Layout arithmetic and example
A worked example
A 72 in inside height with four 0.75 in shelves and no margins leaves 69 in for five openings. Each opening is 13.8 in high, with a 14.55 in shelf-bottom pitch.
Measure and compare a layout
- Measure the finished internal height between the cabinet boundaries.
- Count interior shelves and enter their actual thickness.
- Reserve any top or bottom clearance, then mark the shelf-bottom elevations.
Frequently asked questions
Do four shelves make four or five openings?
Four interior shelves between a fixed top and bottom create five openings.
Are the elevations for shelf tops or bottoms?
They are shelf-bottom elevations measured from the inside bottom before any hardware offset.
Why is the opening height less than inside height divided by openings?
The shelves themselves occupy height. Their total thickness and any reserved margins are subtracted first.
Calculation method: JICWH methodology. Examples are planning assumptions, not product recommendations.