Product
Box
Enter "Units per box" to calculate
Fill in the form and click "Calculate"
3D nesting visualization will appear here
Learn
How the nesting calculator works
Enter the product and the outer size of the shipping box: the calculator turns the outer size into the inner cavity and counts how many units fit per box, and in which arrangement.
What it calculates
The nesting calculator answers how many units of a product fit in one shipping case — the case count, or units per box. It starts from the outer dimensions of the box, because that is how corrugated boxes are ordered and how they meet the pallet, and subtracts the board and the fit clearance to get the cavity the product actually has.
The cavity is the outer size less two board thicknesses and two clearances on each side, and in height also the allowance the FEFCO style needs for its flaps at the closure. The board thickness comes from the flute; a thickness of your own replaces it.
The calculator then tries every orientation of the product and mixes them where that wins a unit: part of a layer turned 90°, or layers of different height stacked together. The result shows the units per box, the grid and a 3D view of the packed box, and flags a requested count that does not fit.
Standards and methods behind it
- FEFCO code: the style decides how much of the height the closure takes, from the catalogue in the FEFCO reference.
- Typical board thickness per flute (E, B, C, EB, BC), the same table the box strength calculator uses.
- Orthogonal packing: units stand square to the box walls in any of their six orientations; the count is whole units along each side of the cavity.
Worked example
A product 95 × 70 × 115 mm in a box of outer size 400 × 300 × 250 mm: FEFCO 0201, C flute (4 mm board), 1 mm fit clearance on each side.
1. Inner length and width
L_i = 400 − 2 × 4 − 2 × 1 = 390 mm; W_i = 300 − 2 × 4 − 2 × 1 = 290 mm
2. Inner height, with the closure allowance of style 0201
H_i = 250 − 2 × 4 − 2 × 1 − 1 × 4 = 236 mm
3. Whole units along each side of the cavity
⌊390 / 95⌋ × ⌊290 / 70⌋ × ⌊236 / 115⌋ = 4 × 4 × 2 = 32
32 units per box. Counting the outer box as if it were the cavity would put more units in the result than the box can hold.
A product 3.75 × 2.75 × 4.5 in in a box of outer size 16 × 12 × 10 in: FEFCO 0201, C flute (0.16 in board), 0.04 in fit clearance on each side.
1. Inner length and width
L_i = 16 − 2 × 0.16 − 2 × 0.04 = 15.61 in; W_i = 12 − 2 × 0.16 − 2 × 0.04 = 11.61 in
2. Inner height, with the closure allowance of style 0201
H_i = 10 − 2 × 0.16 − 2 × 0.04 − 1 × 0.16 = 9.45 in
3. Whole units along each side of the cavity
⌊15.61 / 3.75⌋ × ⌊11.61 / 2.75⌋ × ⌊9.45 / 4.5⌋ = 4 × 4 × 2 = 32
32 units per box. Counting the outer box as if it were the cavity would put more units in the result than the box can hold.
The results are the calculator’s own for these inputs; converted and rounded figures can differ in the last digit.
Common mistakes
- Entering the inner dimensions where the outer ones are expected: the calculator subtracts the board itself, so the cavity would shrink twice.
- Leaving out the fit clearance: a product pressed against the walls tears the box on packing and bulges the walls, which costs compression strength.
- Picking the wrong flute: the board thickness is taken away on both sides, so a BC double wall instead of a B flute takes centimetres out of the cavity.
- Forgetting the closure: a regular slotted container loses board thickness in height at its flaps, a telescope box does not; the FEFCO style decides it.
When this tool is not the right one
- Round products packed in a staggered pattern: a cylinder is counted as its bounding box, so bottles nested between each other are not modelled.
- Inserts, dividers and partitions: the cavity is one empty space.
- Soft and flexible products that take the shape of the box: the count assumes rigid units; an override lets you calculate a count that exceeds the geometric fit.
Questions
How many units fit in a box?
As many whole units as fit along each side of the inner cavity, in the best orientation or mix of orientations. The calculator derives the cavity from the outer box and returns the count and the arrangement.
Do I enter the inner or the outer box dimensions?
The outer ones, as on a box order. The calculator subtracts the board thickness, the fit clearance and the closure allowance of the FEFCO style.
How much fit clearance should I leave?
A millimetre or two per side for rigid products is common; more for products with a tolerance or that go in by hand. The clearance is subtracted on both sides of each dimension.
Why does the calculator turn some units on their side?
Because it can win units: a layer part-turned by 90°, or a layer lying on its side on top of the upright ones, can fill space a single orientation leaves empty. The result shows each layer group.
Every formula with its units and defaults: the calculation method →