Demurrage Calculator
Use our demurrage calculator to calculate port demurrage and container detention charges. Understand free days, daily rates, and how to avoid expensive port storage fees.
Based on benchmark lane pricing, common port charges, and route assumptions rather than live carrier or forwarder quotes.
Freight moves quickly with seasonality, fuel, capacity, and route disruption. Treat these as planning benchmarks, not guaranteed quotes.
demurrage calculator
Medium SERP difficulty
Demurrage and detention charges are some of the most avoidable costs in importing — yet they catch thousands of importers every year. A $2,500 container shipment can accumulate $500–$2,000 in demurrage if customs clearance delays stack up with a port exam and documentation errors.
Demurrage and Detention: How They Work Together
Vessel Arrives at Port
↓
Free Time Period Starts (3–7 days typically)
↓ (if container not picked up)
DEMURRAGE STARTS (port is charging you for their terminal space)
↓
Container Picked Up from Port
↓
Free Time for Return Starts (3–5 days typically)
↓ (if container not returned to depot)
DETENTION STARTS (carrier is charging you for their equipment)
↓
Container Returned to Depot
↓
Charges Stop
2026 Typical Demurrage/Detention Rate Schedule (US)
| Days Beyond Free Time | 20ft Container | 40ft Container |
|---|---|---|
| Days 1–3 | $75–$100/day | $100–$150/day |
| Days 4–6 | $100–$150/day | $150–$200/day |
| Days 7–10 | $150–$250/day | $200–$350/day |
| Days 11+ | $200–$500/day | $300–$600/day |
Peak season and major US ports (LA/LB) often start at the high end of these ranges.
Real Cost Example: A 7-Day Delay
Scenario: $15,000 FOB shipment in a 40ft container. Customs exam selected on day 2, exam completes day 9. 5 days free time.
| Days | Status | Charge |
|---|---|---|
| Days 1–5 | Free time | $0 |
| Day 6 | First demurrage day | $100 |
| Day 7 | Second day | $100 |
| Day 8 | Third day (escalated) | $150 |
| Day 9 | Fourth day (exam ends) | $150 |
| Total demurrage | $500 | |
| Customs broker exam fee | $350 | |
| Total unexpected cost | $850 (5.7% of shipment value) |
And if the trucking appointment can't be made for 3 more days: +$450 more demurrage.
Pre-Arrival Checklist to Avoid Demurrage
- Customs entry filed 5–7 days before vessel arrival
- Commercial invoice and packing list reviewed for accuracy
- ISF filed 24+ hours before vessel departure at origin
- Trucking/dray appointment pre-arranged
- Customs broker engaged and ready
- Warehouse receiving appointment confirmed
- Bill of Lading (or Express B/L waiver) received and transmitted to broker
- Vessel ETA monitored for schedule changes
The best defense against demurrage is a 5-day customs clearance head start — file your entry before the vessel arrives, not after.
Tips for China Importers
- Get 3 freight forwarder quotes for every shipment. Rates for the same lane can vary 20–35% between forwarders. Never book with the first quote you receive.
- Know your LCL vs FCL crossover point. For most lanes, FCL 20ft becomes cheaper than LCL around 15 CBM. At 20+ CBM, FCL almost always wins on cost and transit time.
- Book 4–6 weeks ahead during peak season (July–October). Spot rates spike 30–50% during peak season. Pre-booking or securing a contract rate with your forwarder saves significantly.
- Negotiate free days at the destination port. Standard is 5 free days before demurrage kicks in. Push for 7 days — most forwarders will accommodate regular shippers.
- Always insure your cargo. Marine cargo insurance costs 0.3–0.5% of CIF value. One damaged container without insurance can wipe out months of profit. Never skip it.