Box Fill Calculator

How to use

1. 1Enter the length, width, and height of the small box or item, and pick its unit. Use the item's outside dimensions.
2. 2Enter the length, width, and height of the outer box or container, using its inside dimensions, and pick its unit.
3. 3Read the items per box result and the layout grid, which shows how many fit along the length, the width, and the height.
4. 4Optional: add a weight per item and a maximum box weight to cap the count, and an item quantity to see how many boxes you need.
5. 5Check the orientations table to see every rotation, and use Copy summary to save the result. Everything is calculated in your browser.

About this tool

The Box Fill Calculator answers a question that comes up constantly in shipping, warehousing, moving, retail, and fulfillment work: how many small boxes or items actually fit inside a bigger box, carton, crate, or shelf space. The obvious approach, dividing the outer volume by the inner volume, is almost always wrong, because real boxes cannot be cut or poured. They can only be stacked in whole rows, whole columns, and whole layers, so the empty space left when an item size does not divide evenly into the container is wasted. This tool computes the count the correct way, with orientation-aware grid packing. For each of the up to six ways the inner box can be rotated so its edges stay parallel to the outer box edges, it takes the whole number of items that fit along the outer length, the outer width, and the outer height, multiplies those three counts, and then keeps the single orientation that yields the most units. The result is a guaranteed achievable, axis aligned layout rather than an optimistic upper bound, and the tool shows that layout explicitly as a length by width by height grid, for example five along the length, two across the width, and three layers high. The inner item and the outer container can each be entered in millimeters, centimeters, meters, inches, or feet, and they do not have to use the same unit, which is handy when a product is specified in inches but a carton is specified in centimeters. An orientations table lists every distinct rotation and how many fit each way, with the winning orientation highlighted, so you can see why one way of turning the item beats another. Two optional limits make the tool useful for real loads. A weight per item combined with a maximum box weight caps the count so the packed box stays within a courier, pallet, or shelf weight limit, and the tool tells you when weight, rather than space, is the binding constraint. A quantity to pack reports how many outer boxes you need to hold all of the items and how many end up in the last, partially filled box. A volume comparison panel shows the naive volume only estimate next to the real packed count so the difference between the two is clear. This is well suited to planning master cartons and case packs, estimating boxes per pallet or per container, sizing moving and storage boxes, and quoting shipments. It models uniform, same sized items packed in a simple aligned grid, so it does not handle mixed item sizes, irregular shapes, interlocking patterns, or load bearing and stacking strength, which depend on the specific goods. Every dimension, weight, and quantity you enter is processed locally in your browser and is never uploaded, logged, or sent anywhere.

Free to use. Works in your browser. No signup, no login.