Per diem
What is a per diem charge?
A per diem charge is a daily fee for keeping equipment beyond its free days: most often a chassis or a container that has left the terminal but has not come back. Like demurrage it is a clock with a free window, but the asset is off-terminal and the daily rate pays for equipment that is sitting idle at your site instead of moving for someone.
Where it appears
- Chassis: a daily usage charge from out-gate to return, with free days only where the contract grants them.
- Container per diem at the merchant's premises: free days for the box at the shipper or receiver, then per day.
- Trailer per diem between carriers and leasing companies: a daily rate for a trailer held by a customer.
Counting the days
Free days are defined by the equipment provider's tariff: which days count (business or calendar), where the clock starts (out-gate, delivery), and whether the last day is charged in full. The number that matters is the same as every time-based charge: how fast the free window is visible to the people who can act on it (dispatch, the customer's dock), because per diem is often avoidable with a day's warning. Ocean carriers often call the container version detention. In driver pay, per diem means a daily travel allowance, which is a different thing.