A TEU, or Twenty-foot Equivalent Unit, is calculated by measuring how many standard 20-foot shipping containers a given shipment, vessel, or port volume represents. One standard 20-foot container equals 1 TEU, and a 40-foot container equals 2 TEU. The math is straightforward once you know the conversion values for each container size.
What Counts as 1 TEU
A single TEU represents one container that is 20 feet long, 8 feet wide, and typically 8 feet 6 inches high. This is the baseline unit the entire shipping industry uses to standardize cargo volume, regardless of what’s actually inside the box. When ports report throughput, when shipping lines price freight, and when vessel capacity is listed, TEU is the common language.
The TEU system counts containers by their footprint, not their exact height or cargo type. A High Cube container (9 feet 6 inches tall instead of the standard 8 feet 6 inches) still counts as 1 TEU. A Half Height container (4 feet 3 inches tall, often used for heavy bulk cargo) also counts as 1 TEU. Refrigerated containers, open-top containers, and tank containers all follow the same rule: if the base is 20 feet long, it’s 1 TEU.
Conversion Values by Container Size
Here are the standard conversions used across the industry:
- 20-foot container: 1 TEU
- 40-foot container: 2 TEU
- 45-foot container: 2.25 TEU
- 53-foot container: 2.65 TEU
The 20-foot and 40-foot sizes make up the vast majority of ocean freight. The 45-foot and 53-foot containers appear more often in domestic trucking and intermodal rail transport. Their TEU values are simply their length divided by 20.
How to Calculate TEU for a Shipment
To find the total TEU for any group of containers, multiply the number of containers of each size by their TEU value and add the results together.
For example, say a vessel is carrying 500 standard 20-foot containers and 1,200 forty-foot containers. The calculation would be:
(500 × 1 TEU) + (1,200 × 2 TEU) = 500 + 2,400 = 2,900 TEU
If that same vessel also had 80 forty-five-foot containers on board, you would add (80 × 2.25) = 180 TEU, bringing the total to 3,080 TEU.
TEU vs. Weight Capacity
TEU measures volume slots, not weight. A single 1-TEU container (20 feet) can carry up to about 28,230 kg (roughly 62,170 lbs) of cargo, with a maximum gross weight of around 30,480 kg (67,200 lbs) including the container itself. But the TEU figure tells you nothing about how heavy the cargo is. A vessel rated at 10,000 TEU could be carrying 10,000 containers of feather pillows or 10,000 containers of steel coils. The TEU number stays the same either way.
This distinction matters when you’re planning logistics. A ship or terminal might have TEU capacity available but hit its weight limit long before every slot is filled, especially with dense cargo like machinery or minerals.
How Ports Calculate TEU Throughput
Ports report annual throughput in TEUs to measure how busy they are. The count typically includes both loaded and empty containers, since moving an empty box still requires the same crane lifts, truck turns, and yard space as a full one. The Bureau of Transportation Statistics notes that port profiles in the U.S. include empty containers alongside loaded ones to reflect the full volume of activity at each facility.
Some data sources only count loaded TEU when ranking ports, since adding empty containers wouldn’t change the relative order of the busiest facilities. But for operational planning, the total count matters. If you’re looking at port statistics, check whether the figures include empties, as this can make a noticeable difference in the reported numbers.
Putting TEU Calculations to Use
If you’re a shipper comparing freight quotes, knowing your TEU count lets you compare rates on an apples-to-apples basis. A carrier quoting $1,500 per TEU on a 40-foot container is charging $3,000 for that box (2 TEU × $1,500). If another carrier quotes $2,800 per 40-foot container flat, the second option is cheaper even though it doesn’t use TEU pricing.
If you’re evaluating warehouse or yard capacity, converting your expected container mix into TEU tells you how many ground slots you need. A yard designed for 500 TEU can hold 500 twenty-foot containers, or 250 forty-foot containers, or some combination in between. Planning in TEU keeps the math consistent no matter what container sizes show up.