What is a TEU?

A TEU is a twenty-foot equivalent unit, the yardstick ports use to count container volume. One standard twenty-foot container equals one TEU. A forty-foot container, the more common box on the water today, is two TEU. Counting everything in TEU lets a port add up boxes of different lengths into one comparable number, which is why every volume figure on this site is quoted in TEU rather than in raw box counts.

Why a common unit

Containers come in more than one length. The twenty-footer is the original standard, and the equivalent unit is named for it. A forty-foot box takes the same deck space as two twenties, so it counts as two TEU. There are longer boxes too, forty-five-footers and others, but the twenty-and-forty split carries the trade. A terminal that moved 500 forty-foot boxes and 200 twenty-foot boxes in a month did not handle 700 units, it handled 1,200 TEU. The unit measures capacity and throughput, not the number of physical containers.

Loaded imports, loaded exports, empties

A monthly port release does not give you one TEU number, it gives three streams, and the split is the whole story. Loaded imports are full boxes coming in. Loaded exports are full boxes going out. Empties are containers moving with nothing in them, repositioned to wherever the next load waits. For a US importer the loaded-import line is the demand read, the count of full boxes actually landing. A big empties number is a repositioning tell, carriers hauling equipment back toward Asia to reload, not freight anyone is buying.

Worked example: decomposing a month

The chart above is the Port of Los Angeles monthly volume, broken into those three streams. Read the latest month and the loaded-import bar is the one that matters for import demand, full boxes hitting the dock. Set it against the loaded-export bar and you can see how lopsided the trade is at a West Coast gateway, far more coming in than going out. The gap gets filled by the empties stream, boxes shipped back overseas to be loaded again. One month's total TEU tells you how busy the port was. The split tells you what kind of busy.

A capacity unit, not a value

One caution. TEU counts boxes, not what is in them or what they are worth. A container of televisions and a container of patio furniture are each one forty-foot box, two TEU, whatever the invoice says. Port volume is a throughput measure, so a rising TEU count means more boxes moving, not necessarily more dollars of trade. Read it for flow, and read the loaded-import stream when you want the cleanest signal of import demand.

The Dwell reports TEU volumes as the port authorities publish them, dated to the month. For how to read a fresh monthly release three ways, see reading the monthly TEU release.