How Many Boxes Fit in a Container
The Container Loading Calculator works out how many boxes fit in a container, so you can plan a shipment before you book one. Enter your cargo's length, width, height, and weight, pick a container, and it returns the exact unit count with volume and weight utilization.
It supports the standard 20', 40', 40' High Cube, and 45' High Cube containers, plus any custom inner dimensions. The tool tests cargo rotation to maximize the fit and caps the result by both container volume and maximum payload — useful for exporters, freight forwarders, and anyone planning a stuffing job.
How to Use the Calculator
Select a container type
Choose 20', 40', 40' HC, or 45' HC. Need a non-standard size? Tick Custom Dimensions and enter the inner length, width, height, and max payload yourself.
Choose your units
Switch dimensions between cm and in, and weight between kg and lbs, using the unit toggles. The calculator converts between systems automatically.
Enter cargo details
Type the length, width, and height of one cargo unit, then add the weight per unit so the result respects the payload limit. Set a Quantity Available to cap the count, or leave it empty for unlimited.
Calculate and read the results
Keep Allow Rotation on to test every orientation, then press Calculate (or Enter). You get the Units Fit, volume and weight utilization bars, the per-axis arrangement, and the remaining capacity.
Features
Standard Container Types
Pick 20', 40', 40' High Cube, or 45' High Cube with their real ISO inner dimensions and payload limits built in.
Custom Container Support
Enter custom inner length, width, height, and max payload for non-standard containers, trailers, or storage spaces.
Rotation Optimization
With Allow Rotation on, the tool tests every box orientation and keeps the one that fits the most units.
Volume & Weight Limits
The fit is capped by both container volume and maximum payload, so the count never exceeds either constraint.
Metric & Imperial Units
Work in cm or inches and kg or lbs — the calculator converts between systems on the fly.
Quantity Limiting
Enter how many units you actually have to ship and see how much space they need and how much remains.
Arrangement Breakdown
See the chosen orientation and how units stack along the length, width, and height of the container.
Remaining Capacity
View the leftover volume in CBM (m³) and the unused payload, both as totals and as percentages.
Frequently Asked Questions
How do you calculate how many boxes fit in a container?
The calculator divides each container dimension by the matching box dimension and multiplies the three whole-number counts — units along the length × along the width × along the height. It then caps that figure by the container's maximum payload (and your quantity, if set), so the result respects both volume and weight.
How many cartons fit in a 20ft vs 40ft container?
It depends entirely on your carton size, but a 40' container has roughly twice the inner length of a 20' — about 12.03 m versus 5.9 m — at the same 2.35 m width and 2.39 m height, so it holds close to double the units. Enter your real carton dimensions and select each container to compare the exact counts side by side.
What does Allow Rotation do?
When enabled, the calculator tries every distinct orientation of your box (up to six rotations) and keeps the one that fits the most units. With it off, it only uses the original length × width × height orientation you entered. Rotating boxes 90° often does fit more.
Why is the real number lower than the theoretical fit?
This calculator assumes uniform, box-style cargo packed in neat rows with no gaps. Real loading loses space to pallets, dunnage, air gaps, and uneven box sizes. For a conservative estimate, reduce the container's inner dimensions slightly using Custom Dimensions before you calculate.
Why does Weight Utilization show N/A?
That appears when the Weight per Unit field is empty or zero. Without a unit weight the tool can't compare your load to the payload limit, so it skips the weight check. Enter the weight of each cargo unit to see weight utilization and the remaining payload.
How is container utilization (CBM used) calculated?
Volume utilization is the total cargo volume divided by the container's internal volume, shown as a percentage. CBM Used is that cargo volume expressed in cubic meters (m³). The remaining capacity shows the leftover m³ and unused payload so you can see which constraint — space or weight — is the bottleneck.
Can I calculate for non-standard containers?
Yes. Tick Custom Dimensions and enter the inner length, width, height, and maximum payload of any container, truck trailer, or storage space. The dimensions pre-fill from your selected standard size, so you can tweak from there.
Are these container dimensions accurate?
The built-in inner dimensions follow ISO standard shipping-container specifications, but actual sizes vary slightly between manufacturers. For critical shipments, confirm the exact figures with your carrier or container provider and use Custom Dimensions if they differ.
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