Demurrage & Detention Calculator

How the Demurrage & Detention Calculator works

Demurrage and detention are calculated separately. For each, enter the start and end dates, the free days and your daily rate tiers. The calculator counts the elapsed days, subtracts the free days and prices the remaining chargeable days through the tiers, then multiplies by the number of containers.

You choose whether both the start and end dates count as days, because carriers differ. No free days or rates are built in: use the figures from your carrier's tariff or contract.

Formula

Chargeable days = max(0, elapsed days − free days)
Charge          = Σ (days in each tier × tier rate) × containers
Total           = demurrage + detention

Worked example

Demurrage: 14 days at the terminal, 5 free days, 2 containers
Chargeable days = 9
Days 1–4 at 75  = 300
Days 5–9 at 150 = 750
Per container   = 1,050 → 2 containers = 2,100

When to use it

• Estimating the cost of a customs delay or late collection.
• Checking a carrier's demurrage or detention invoice.
• Deciding whether paying for faster clearance or extra free time is worth it.

Limitations

Results are estimates based on the values and rates entered. Some carriers combine demurrage and detention into a single charge, count only working days, or charge port storage separately. Check the tariff that applies to your booking. The difference between the two charges is explained in Demurrage vs Detention.