Key takeaways
- Demurrage is time inside the terminal; detention is time outside it.
- Both accrue daily once free time is exceeded, and add up fast.
- They are a common, largely avoidable cost leak in transportation.
- Reducing them takes visibility and faster container and equipment turns.
How do demurrage and detention work?
When a container arrives, the shipper gets a set number of free days to pick it up from the terminal. Keep it there past that window and demurrage accrues per day. Once the container leaves the terminal, the shipper gets free time to unload and return the empty; hold the carrier's equipment beyond that and detention accrues per day. The line between them is the terminal gate.
The charges are driven by delays: slow customs clearance, no appointment or chassis, congested yards, or slow unloading and empty returns. Because they accrue daily and often on many containers at once, they become a significant and largely avoidable cost. Reducing them means seeing at-risk containers early and acting, scheduling pickups, chassis, and returns before the clock runs out.
How to reduce demurrage and detention
- Track free-time clocks per container and flag at-risk ones early.
- Schedule pickups, chassis, and empty returns before deadlines.
- Surface the exceptions in a control tower so teams act in time.
- Analyze causes to fix the systematic sources, not just pay the bills.
Demurrage and detention in a logistics operation
An importer discovers a steady leak of per-diem charges across its container flow. Putting free-time clocks and container status into a control tower surfaces at-risk boxes days before charges hit, so the team books pickups and empty returns in time. The avoidable charges fall, and the remaining ones are traced to specific bottlenecks to fix.
Frequently asked questions
What is the difference between demurrage and detention?+
Demurrage is charged for keeping a container inside the port or terminal past the free time. Detention is charged for holding the carrier's container or equipment outside the terminal too long. The simple rule: demurrage is inside the gate, detention is outside it.
How can a company reduce these charges?+
By making the free-time clocks visible and acting before they expire: scheduling pickups, chassis, and empty returns on time, clearing customs early, and surfacing at-risk containers in a control tower. Analyzing the root causes then fixes the systematic sources rather than treating the charges as a cost of doing business.
Written and reviewed by the InfoSun operations team. Last updated July 13, 2026.