Calculate truck detention fees and container demurrage charges from wait time, free time, and hourly or daily rates, including tiered port rate structures.
Truck Detention & Demurrage Fee Formula
DF = max(T - FT, 0) * R (exact-time mode, before an optional cap)
DEM = ceil(max(TD - FD, 0)) * DR * N (flat-rate estimate)
- DF is the estimated truck detention fee ($)
- T is the total time the truck spent at the facility (hours)
- FT is the agreed free time before charges begin (hours)
- R is the detention rate ($ per hour)
- DEM is the estimated demurrage fee ($)
- TD is the total tariff-counted days at the terminal, on the same counting basis as FD
- FD is the number of free days allowed
- DR is the demurrage rate ($ per container per day)
- N is the number of containers
The detention mode subtracts agreed free time from total facility time, with a minimum of zero, and multiplies billable time by the hourly rate. Enter total hours or 24-hour check-in and check-out times. An earlier check-out assumes the next day and a stop shorter than 24 hours; equal clock times require total-hours entry. Billing and cost settings can round time beyond the free window up to 15, 30, or 60 minute increments, apply a fee cap, and compare the fee with operating cost for actual time beyond free time. Blank means no cap; a zero cap limits the fee to $0. Blank operating cost omits that comparison.
The demurrage mode subtracts free days from total tariff-counted days, floors the difference at zero, and rounds partial chargeable days up for this simplified estimate. Use comparable counts from your tariff: free-time rules can use working days while charges use calendar days, so elapsed time alone may not give the correct bill. Flat or tiered daily rates are supported. Tier 1 applies first, then tier 2, then tier 3 for the remainder. A zero tier length skips that tier. Blank tier 2 rate inherits tier 1; blank tier 2 length means zero days; blank tier 3 rate inherits the effective tier 2 rate. Container counts and tier lengths must be whole numbers.
Illustrative Detention and Demurrage Assumptions
The figures below are illustrative input assumptions, not verified current market rates or a universal free-time allowance. Use the rates, counting rules and free time in your own agreement or tariff. The calculator starts with 2 free hours, 4 free days and 1 container; these are editable assumptions.
| Charge type | Free time | Illustrative rate |
|---|---|---|
| Dry van detention | 2 hours | $50 to $100 per hour |
| Reefer detention | 2 hours | $75 to $125 per hour |
| Specialized or hazmat detention | 1 to 2 hours | $100 to $150 per hour |
| Demurrage, tier 1 (first days over) | 2 to 7 free days | $75 to $175 per container per day |
| Demurrage, tier 2 | n/a | $150 to $300 per container per day |
| Demurrage, tier 3 (10+ days over) | n/a | $300 to $500+ per container per day |
The next table compares hypothetical detention rates with an assumed operating cost of $90 per hour. This is an arithmetic example, not a current industry cost estimate. It considers only actual waiting time beyond the free period, excluding free time and any extra billed time created by rounding. Enter your own relevant hourly cost to estimate this comparison.
| Detention rate paid | Assumed operating cost per hour | Net per detained hour |
|---|---|---|
| $50 | $90 | -$40 shortfall |
| $75 | $90 | -$15 shortfall |
| $90 | $90 | Break even |
| $100 | $90 | +$10 recovered |
The operating cost comparison shows estimated fee minus the entered operating cost for time beyond the free window. It is not total trip profit or the cost of the whole stop; billing increments and a fee cap can also affect the comparison.
Truck Detention & Demurrage Fee Example Problems
Example 1: Hourly truck detention. A driver checks in at a receiver at 8:00 AM and checks out at 1:30 PM, for 5.5 hours at the facility. The rate confirmation allows 2 free hours and pays $75 per hour of detention. Billable time is 5.5 – 2 = 3.5 hours. The detention fee is 3.5 * 75 = $262.50. If the carrier’s operating cost is $90 per hour, the operating cost for time beyond free time is 3.5 * 90 = $315, so the fee leaves a $52.50 shortfall.
Example 2: Tiered container demurrage. Two containers sit at a port terminal for 11 days with 4 free days, leaving 7 chargeable days each. The tariff bills the first 4 chargeable days at $110 per day and the next days at $220 per day. Each container has an estimated charge of 4 * 110 + 3 * 220 = 440 + 660 = $1,100, so the total demurrage for both containers is 2 * 1,100 = $2,200.
Truck Detention & Demurrage Fee FAQ
What is the difference between detention and demurrage? Detention is a time charge for holding transportation equipment or a driver beyond the allowed free period, most commonly billed per hour when a truck waits at a shipper or receiver. Demurrage is a daily charge for a container that stays inside a port or rail terminal past its free days. A related charge, per diem (also called container detention), applies per day when a container is kept outside the terminal beyond the allowed time. The same delay can trigger more than one of these charges on a single shipment.
When does detention time start? The start time and eligibility depend on the agreement, appointment and facility requirements. If the agreed clock starts at 9:00 AM and allows 2 free hours, billable time begins at 11:00 AM. There is no universal 2-hour entitlement. Keep timestamped arrival and departure records and follow the contract’s notification requirements.
Are demurrage charges negotiable? Free time, rates and possible reductions depend on the tariff or service contract. Billing disputes and invoice requirements are separate from this arithmetic estimate. U.S. ocean-shipping rules and their application can change; consult the Federal Maritime Commission’s current detention and demurrage information and the applicable agreement. The calculator does not establish that a charge is lawful, payable or refundable.
