Container loading calculations, done right from the start
From the CBM formula to 20ft/40ft container specs, piece-count calculation, single vs multi-layer loading, and weight limit pitfalls — a practical reference for forwarders and import/export teams.
CBM (Cubic Meter) expresses cargo volume in cubic meters (m³). It's the basis for ocean freight pricing and the first metric for judging how much cargo fits in a container.
Basic CBM formula
CBM = Length(m) × Width(m) × Height(m) × Quantity
When entering in centimeters: CBM = L(cm) × W(cm) × H(cm) ÷ 1,000,000 × Quantity
Worked example
Shipping 50 boxes measuring 120cm × 80cm × 100cm:
120 × 80 × 100 ÷ 1,000,000 × 50 = 4.8 CBM
⚠️ Practical note: For palletized cargo, calculate using the final outer-packing dimensions including pallet height (typically 12–15cm). Forgetting the pallet is a common cause of accidentally exceeding container height.
FCL vs LCL — what CBM decides
FCL (Full Container Load)
You use an entire container by yourself
Usually favorable above ~15 CBM
No mixing with other shippers → safer handling
Plan exact piece counts precisely with MyNore
LCL (Less than Container Load)
Multiple shippers' cargo consolidated into one container
Usually favorable for small volumes (under ~15 CBM)
Priced as rate-per-CBM × total CBM
Always check for a minimum-CBM clause
Step 02
Container specs and weight limits by type
Internal dimensions and max payload (per ISO 668) for standard international containers. Real-world containers vary slightly by manufacturer and carrier, so always check the CSC plate figures first.
Type
Internal length
Internal width
Internal height
Internal volume
Max payload
20ft Standard (Dry)
589 cm
235 cm
239 cm
~33 CBM
21,727 kg
40ft Standard (Dry)
1,203 cm
235 cm
239 cm
~67 CBM
26,680 kg
40ft HC (High Cube)
1,203 cm
235 cm
269 cm
~76 CBM
26,500 kg
When to choose 40ft HC: pick High Cube when cargo height exceeds 220cm, or when multi-layer stacking needs to make the most of available space. The extra ~30cm of height adds roughly 13% more volume.
A note on 20ft weight: MyNore uses a conservative figure (MGW 24,000 kg). Newer containers built after 2005 may carry an MGW of 30,480 kg, pushing max payload up to ~28,200 kg. Always verify the actual CSC plate.
Step 02-1
Truck (wing body / box truck) bed specs
Inland transport needs wing-body and box-truck load planning just as often as ocean containers. MyNore calculates truck cargo beds with the exact same algorithm. Below are representative specs commonly used in practice.
Vehicle
Internal length
Internal width
Internal height
Payload (typical)
1t Box Truck
280 cm
160 cm
160 cm
1,000 kg
2.5t Wing Body
430 cm
205 cm
200 cm
2,500 kg
5t Wing Body
620 cm
234 cm
230 cm
5,000 kg
11t Wing Body
950 cm
235 cm
245 cm
11,000 kg
⚠️ Truck bed dimensions are not standardized. Unlike ocean containers (ISO 668), a truck's cargo bed can vary significantly depending on the body manufacturer, model year, and axle configuration. The table above shows representative values — always confirm the actual assigned vehicle's bed dimensions before finalizing your load plan. If you know the exact dimensions, entering them in MyNore's Custom tab is the most accurate option.
Wing body vs. box truck — what's the difference?
Wing Body
Side panels open upward like wings
Forklift-friendly side loading → faster turnaround
Ideal for palletized cargo and industrial materials
Common from 2.5t and up
Box Truck
Fully enclosed box, loaded through a rear door
Weather- and contamination-resistant, good for boxed parcels
The standard for 1t-class urban delivery
Watch the height limit (~160cm for 1t-class)
Step 03
How to calculate piece count
Simply dividing "container volume ÷ cargo CBM" gives you a number, but it differs significantly from the actual quantity that fits. Even with box-shaped cargo, stacking always leaves gaps. In practice, volume efficiency of 70–85% is the realistic benchmark.
Why does the simple calculation fall short?
Orientation constraints — cargo that fits rotated but not in its default orientation
Width remainder — cargo width doesn't divide evenly into the 235cm width
Hitting the weight limit — volume remains but weight capacity runs out first
Safety gaps — required spacing between cargo reduces the real count
💡 MyNore tip: enter your cargo's length, width, height and weight, and MyNore automatically calculates the exact piece count and layout using two methods — optimal 2D floor packing (single-layer) and tower-first mixed stacking (multi-layer). No manual-calculation errors.
Should you allow rotation?
Rotating cargo 90° (switching lengthwise ↔ crosswise) can sometimes fill leftover space better. But some cargo can't be rotated due to directional labels or fragile faces — control this per item using the Allow rotation / Lock orientation option on each cargo card.
Step 04
Single-layer vs multi-layer (mixed) loading — when to use which?
🟦 Single-layer mode
Placed in a single layer on the floor only
Use when cargo can't be stacked (fragile or irregular items)
Larger-footprint cargo placed first
Auto-optimizes lengthwise/crosswise when rotation is allowed
Simple, intuitive calculation
🟩 Multi-layer mode
Stacks upward to use vertical space
For box- or pallet-type cargo that can be stacked
Largest-footprint cargo anchors the base
Smaller cargo automatically mixed into remaining height
Significantly higher space efficiency than single-layer
Multi-layer mode — tower-first stacking
MyNore's multi-layer mode uses a tower-first approach. Rather than laying down a full floor of layer 1 before starting layer 2, it fills one floor position all the way up to its max tier first, then does 2D floor placement tower by tower. The largest-footprint cargo becomes the base at the bottom, and smaller cargo is automatically mixed into any remaining height.
Setting max tiers: you can manually specify the maximum stack height your cargo can physically bear. Leave it blank and it's auto-calculated as container height ÷ cargo height.
Step 05
Weight limit pitfalls
It's very common in practice for cargo to fit by volume but hit the weight limit first. Dense cargo like steel or machinery especially needs weight checked before volume.
Weight-limit rule for multi-layer stacking
Base formula (items with a max tier of 2 or more)
Max weight that can be stacked on top = (Max tiers − 1) × its own weight
Example: a 100kg item with max 2 tiers → up to 100kg can be placed on top
For cargo limited to a single vertical tier by height (i.e. tall items), only cargo equal to or lighter than itself can be stacked on top. Placing heavier cargo on top of lighter cargo is blocked.
Practical note: the CSC plate figures on the container door are the actual authoritative reference. Carrier policy and road weight regulations (axle weight, gross weight) may permit less than the structural limit. MyNore's figures are for reference only.
Step 06
Practical pre-loading checklist
Did you calculate CBM using final outer-packing dimensions (including pallets/packaging)?
Does cargo height stay within internal container height (239cm / 269cm)?
Is total cargo weight under the container's max payload?
Have you locked orientation on cargo that can't be rotated (directional labels, fragile faces)?
Have you set a minimum safety gap between cargo? (5cm default)
For multi-layer stacking, can the bottom cargo bear the weight above it?
Have you confirmed the actual measured container dimensions with your carrier/forwarder?
Have you checked the max payload on the CSC plate?
FAQ
Frequently asked questions
Q. My CBM checks out, so why doesn't it all fit?
Even when total volume is smaller than the container's volume, actual placement wastes space. This happens when cargo dimensions don't divide evenly into the 235cm width, when height constraints prevent a full tier, or when there are orientation constraints. Check actual space usage with MyNore's layout drawing.
Q. Which is better — 40ft or 40ft HC?
If cargo height is 210cm or under and stacking is difficult, a standard 40ft is enough. If cargo is tall, or multi-layer stacking can add more tiers, HC wins. Freight difference varies by carrier but HC is usually a bit more expensive, so compare based on volume utilization.
Q. Do I need to manually set "max tiers" in multi-layer mode?
Leave it blank and it's auto-calculated as container height ÷ cargo height. If the actual number of tiers your cargo can bear is lower than that, set it manually and lower. For example, if cargo can only be stacked 3 tiers high, set "max tiers = 3" for an accurate calculation.
Q. Can I use MyNore's results directly for an actual shipment?
Use it as a reference only. For an actual shipment, separately confirm with your carrier/forwarder and check on-site conditions, cargo securing methods, and the container's actual measured state.
More Resources
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