Container loading calculator: how many containers will this shipment need?

Tell it how big and heavy your cargo is, and it tells you the cheapest way to pack it — then turn the result into a Drayage booking with one click.

A container loading calculator answers one question before you book the space: "This pile of cargo — how many containers, which type, and how should it be packed?" Give it your cargo dimensions and weights, and it runs a 3D packing simulation (4 strategies race, the best wins) to tell you the fewest containers you need, the utilization of each one, and the exact loading order. Then, with one click, the result becomes Drayage booking drafts — container type, total weight and utilization carried over automatically, so you only fill in the port and the expected sailing date.

How to use it: 5 steps#

Step 1 — Pick the container type

Create a loading plan and pick the container type: 20-foot, 40-foot, 40-foot high cube, 45-foot — or let several types race together (mixed calculation) and see which combination uses the fewest containers. The built-in types come with standard internal dimensions; if you use a non-standard or special container, add your own type first in the container library (Container Types page) with its inner length/width/height, door size and max payload.

Step 2 — Enter your cargo

Three ways to enter cargo — pick whichever is easiest: (1) Type it in by hand: for each cargo type, enter length/width/height (in meters), weight per piece (kg) and quantity. (2) Excel import: download the template, fill it in (columns are bilingual Chinese/English), upload it — up to 1,000 lines at a time. (3) One-click import from an OMS sales order: the order lines come in automatically with the packing dimensions from your SKU master data, zero typing.

Step 3 — Set the rules (optional)

The rules come with sensible defaults — you can skip this step entirely. If you need them: rotation (whether each box may be turned around), max stack layers for the same box, "heavy never on light" (how much weight the top box may bear, default 500 kg), and segregation for things that must not mix (e.g. food vs. chemicals — they go into separate containers or separate zones). Total container weight is always a hard limit and cannot be turned off.

Step 4 — Review the 3D plan

Hit "Calculate" and the system simulates the packing in 3D: how many containers, the utilization of each one (e.g. 87%, 91%), and where every piece goes — heavy cargo at the bottom, evenly distributed, with the center of gravity shown so you can spot a lopsided load before it becomes an axle-weight problem on the road. Flip through containers one by one; if the result is not ideal, adjust the rules and re-calculate — old results are replaced, nothing piles up.

Step 5 — One-click output

Happy with the plan? Two outputs, one click each: (1) Generate Drayage booking — creates one booking draft per container (a 2-container plan creates 2 drafts), with container type, total weight, cargo list and utilization filled in; you only complete the port and expected sailing date in Drayage. (2) Loading guide — a printable sheet for the warehouse floor: the exact loading order (load from the far end outward, bottom up), per-container cargo lists, weights and utilization. Print it and stick it on the container door.

FAQ#

The calculator says it does not fit — what now?

Don't panic — the error message tells you exactly why: a single piece heavier than the container's max payload, a piece too big in every orientation, or simply more cargo than the container holds. Three ways out: (1) Check your numbers — a misplaced decimal in length or weight is the most common cause. (2) Allow rotation so boxes can be turned. (3) Let several container types race (mixed calculation) or switch to a bigger type (e.g. 40-foot high cube instead of 40-foot standard). The system always picks the fewest containers.

Can I change the container dimensions?

Yes — but only for container types you created yourself. The built-in types (20'/40'/40'HQ/45') follow international standards and are locked. Your custom types are fully editable (length/width/height, door size, payload, and even the code/name), and you can also disable one you no longer use instead of deleting it.

What if my cargo dimensions are wrong or weights missing?

Fix the numbers in the cargo list and re-calculate — the old result is automatically discarded. Missing weight is treated as 0 kg, which underestimates the real load and can produce a plan that overloads the container in reality; always fill in real weights before booking. The Excel template validates common mistakes on upload.

How accurate is the result? Can the warehouse trust it?

The algorithm is a well-known 3D packing heuristic (Extreme Point, 4 strategies competing for the best result), and it respects real-world constraints: total weight never exceeds the container's max payload, heavy cargo goes to the bottom and is spread evenly, and the center of gravity is reported so you can catch a lopsided load. The loading guide gives the warehouse the exact loading order (far end first, bottom up) — but do a final visual check on the floor: cardboard compresses, pallets vary, and the real world always has the last word.

Do I have to generate the booking right away?

No. A calculated plan stays as a draft you can revisit, tweak and re-calculate as many times as you like. Generate the booking only when the cargo list is final — once generated, the plan is marked confirmed and its cargo list is locked. Generating twice does not create duplicates: the second call simply returns the existing booking numbers.