How to Calculate Detention Pay Owed
Detention pay = (Total time at facility − Free time allowance) × Hourly rate. The formula is simple. The mistakes happen in determining when the free time clock starts, whether the truck arrived before or at the appointment time, and whether partial hours are billable. This guide walks through every scenario.
The Basic Formula
Detention Owed = (Departure Time − Clock Start) − Free Time Allowance) × Hourly Rate
Where Clock Start is the earlier of: actual GPS arrival or scheduled appointment time (check your rate confirmation — this varies).
Standard Example
| Detail | Value |
|---|---|
| Scheduled appointment | 10:00 AM |
| GPS arrival | 10:08 AM |
| Free time allowance | 2 hours |
| Free time ends | 12:08 PM |
| GPS departure | 3:30 PM |
| Detention billable time | 3 hrs 22 min (3.37 hours) |
| Rate | $75/hour |
| Detention owed | $252.50 |
The Three Variables That Change Your Calculation
Variable 1: When Does the Free Time Clock Start?
This is the single most commonly miscalculated element of detention pay. Your rate confirmation will specify one of these clock-start conditions:
Option A: Clock starts at scheduled appointment time The most carrier-favorable reading. If the truck arrives on time, free time begins at the appointment. A truck arriving at 10:00 AM for a 10:00 AM appointment starts the two-hour clock at 10:00 AM, regardless of when a door is assigned.
Option B: Clock starts at actual arrival If the truck arrives 30 minutes early (9:30 AM for a 10:00 AM appointment), free time begins at 9:30 AM. This can reduce your billable detention if the truck departs before free time expires.
Option C: Clock starts at door assignment Some rate confirmations specify that free time begins when the carrier is assigned to a door — not when the truck enters the facility. Under this language, a truck sitting in the staging lot for two hours before getting a door assignment hasn’t started the free time clock yet. This is common at certain large shippers and warehouse facilities.
What to do: Read every RC before the load runs. Underline the clock-start language. If it’s ambiguous, your default should be the interpretation most favorable to you — but document the actual arrival time regardless, because you may need to argue the interpretation later.
Variable 2: Partial Hours
If your rate confirmation specifies an hourly rate without language about minimum billing increments, you should bill by the minute (expressed as a decimal of an hour).
Conversion table:
| Minutes | Decimal |
|---|---|
| 15 min | 0.25 hr |
| 20 min | 0.33 hr |
| 30 min | 0.50 hr |
| 40 min | 0.67 hr |
| 45 min | 0.75 hr |
| 50 min | 0.83 hr |
Some rate confirmations specify minimum billing increments — “detention billed in 30-minute increments” or “minimum 1-hour billing once free time expires.” If yours does, apply that increment.
Variable 3: Multiple Stops on One Load
Detention can occur at pickup, at delivery, or at both. Each stop is calculated separately, and each has its own clock-start and free time allowance.
Multi-stop example:
Pickup:
- Appointment: 7:00 AM | Arrival: 7:05 AM | Departure: 10:20 AM
- Billable: (10:20 − 7:05) − 2:00 = 1 hr 15 min = $93.75 at $75/hr
Delivery:
- Appointment: 2:00 PM | Arrival: 2:15 PM | Departure: 5:30 PM
- Billable: (5:30 − 2:15) − 2:00 = 1 hr 15 min = $93.75 at $75/hr
Total detention invoice: $187.50
Submit as a single invoice with two separate detention detail sections, one per facility.
Calculating When the RC Doesn’t Specify a Rate
If your rate confirmation doesn’t include a detention rate, you’re in a weaker position — but you’re not necessarily without recourse.
Options:
- Negotiate a rate before accepting the load. If you expect a high-detention facility, ask the broker to add a detention rate to the RC before you commit. This is the cleanest solution.
- Invoice at industry standard rate. Some carriers bill at $50–$75/hour even without an explicit RC rate, citing “standard industry practice.” Success varies by broker.
- Keep records anyway. Even if you can’t collect now, detention history by facility informs future load acceptance decisions.
Common Calculation Mistakes
Mistake: Using wall clock time instead of GPS time Driver-noted times and GPS-verified times often differ by 15–30 minutes. Always base your calculation on GPS data. It’s harder to dispute and more accurate.
Mistake: Starting the clock at arrival when RC specifies appointment If your RC says free time starts at appointment time, using actual arrival time could undercount your detention when the truck arrived on time. Calculate both ways and apply the RC language.
Mistake: Forgetting to account for the appointment, not just the hours A truck that arrived at 9:30 AM for a 10:00 AM appointment and departed at 12:30 PM has 2 hours 30 minutes of total time at facility — but free time starts at 10:00 AM (the appointment), not 9:30 AM. Billable detention: 30 minutes.
Mistake: Not calculating to the minute At $75/hour, 15 minutes is $18.75. Rounding to the nearest hour loses money on every invoice.
Quick Reference: Detention Calculation by Rate
| Rate | Per 15 min | Per 30 min | Per 45 min | Per hour |
|---|---|---|---|---|
| $50/hr | $12.50 | $25.00 | $37.50 | $50.00 |
| $60/hr | $15.00 | $30.00 | $45.00 | $60.00 |
| $75/hr | $18.75 | $37.50 | $56.25 | $75.00 |
| $85/hr | $21.25 | $42.50 | $63.75 | $85.00 |
| $100/hr | $25.00 | $50.00 | $75.00 | $100.00 |
Related Articles
- What Is Detention Pay in Trucking?
- Free Time in Trucking: What It Means and How It’s Calculated
- Detention Pay Rates by Load Type (2026)
- Detention Pay Invoice Template (Free Download)
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