On the ops desk, dwell time is the measurement that shows where a shipment is losing days: a container waiting at the terminal for clearance, a truck, or an onward connection is accumulating dwell whether or not anything has gone wrong. Rising dwell at a port points to congestion or slow document handling, and it drives the decision to pull the container sooner, re-sequence clearance and trucking, or route future bookings elsewhere. Dwell time is not the same as free time: dwell time measures how long the box actually sat, while free time is the contractual allowance before demurrage or detention charges begin to accrue, so dwell only starts drawing demurrage or detention charges once it runs past the free time.
Glossary
Dwell Time
The time cargo or a container sits stationary at a node, such as a port, terminal, or depot, between one movement and the next.