If you ship freight regularly, the per-mile rate is the number that drives your total cost. But that rate is not a single fixed figure — it shifts based on fuel prices, lane demand, load type, and how many empty miles the truck has to drive to pick up your freight. Understanding what goes into the per-mile calculation helps you compare quotes accurately and spot when a rate is fair or padded.
What Goes Into Freight Cost Per Mile
Carriers build their per-mile rate from several cost layers. Here is the breakdown:
Base operating cost. This covers driver wages, truck financing, insurance, and scheduled maintenance. For a standard dry van operation, the base cost runs $1.80 to $2.20 per mile. Reefer operations run higher because the refrigeration unit burns fuel and requires more maintenance.
Fuel surcharge. Diesel prices change weekly, and carriers pass that volatility to shippers through a fuel surcharge. The surcharge is calculated using the national average diesel price and the truck's average fuel economy (around 6 to 7 mpg for a loaded van). When diesel is $4.00 per gallon, the fuel component adds roughly $0.60 per mile.
Lane and demand factors. A lane with balanced freight in both directions costs less because the truck finds a return load. A lane where freight moves one way but not the other — say, Seattle to Spokane — costs more because the carrier has to deadhead the truck back empty or find a low-paying backhaul.
Accessorial charges. Liftgate service, inside delivery, detention time, and residential pickup each add to the total. These are not per-mile costs, but they show up in the final invoice and affect your effective cost per mile.
Typical Per-Mile Rates for Pacific Northwest Lanes
Rates vary by lane, but here are rough ranges for common routes in Washington and Oregon:
| Lane | Van Rate/Mile | Reefer Rate/Mile | Notes | |------|---------------|------------------|-------| | Seattle to Portland | $2.80–$3.40 | $3.20–$3.90 | Balanced lane, good backhaul availability | | Seattle to Spokane | $3.20–$4.10 | $3.60–$4.50 | One-way lane, limited backhaul | | Tacoma to Kent (local) | $4.00–$6.00 | $4.50–$6.50 | Short haul, minimum charge applies | | Kent to Tacoma port | $3.50–$5.00 | — | Drayage lane, chassis fees apply | | Portland to Seattle | $2.70–$3.30 | $3.10–$3.80 | Balanced return lane |
Short-haul moves under 50 miles often cost more per mile than long-haul because carriers apply a minimum charge. A 20-mile drayage from the Port of Tacoma to a Kent warehouse might cost $150 to $250 total — that works out to $7 to $12 per mile, but the carrier is charging for the truck's time, not just the distance.
Spot Market vs Contract Rates
The per-mile rate you get depends on whether you are booking on the spot market or under a contract.
Spot market rates change daily. When freight volume spikes in a market and truck capacity is tight, rates jump 20 to 40 percent in a week. When capacity loosens, rates drop. Spot market is good for one-off shipments but unpredictable for budgeting.
Contract rates lock in a fixed per-mile price for a set period — usually 6 to 12 months. The carrier gets predictable volume, and you get predictable pricing. For shippers moving freight on the same lanes week after week through the Kent Valley or along the I-5 corridor, contract rates save money over time and eliminate the surprise of a $4.50/mile spot quote on a busy Friday.
A full freight shipping cost breakdown covers the broader pricing picture — LTL vs FTL, accessorial charges, and how weight and dimensions affect your total bill beyond just the per-mile rate.
What Drives Rate Increases on Specific Lanes
Some lanes cost more for reasons that have nothing to do with distance:
Port drayage lanes. Moves out of the Port of Seattle or Port of Tacoma involve terminal access fees, chassis rental, and wait times that can stretch to 3 hours during peak season. The per-mile rate looks high, but the carrier is charging for dwell time. Ocean trucking and drayage operations carry these costs by nature.
Mountain routes. Freight moving east over the Cascades — Seattle to Yakima, Portland to Bend — costs more because the route is slower, fuel consumption increases on grades, and winter weather adds risk. Carriers factor this into the lane rate.
Seasonal demand. Retail freight peaks from August through November as importers build inventory for the holiday season. During these months, per-mile rates on lanes out of the Ports of Seattle and Tacoma can increase 15 to 25 percent. Booking early helps you lock in a rate before the peak hits.
Getting an Accurate Per-Mile Quote
When you request a freight quote, provide the carrier with:
- Origin and destination ZIP codes
- Pickup and delivery dates (or a window)
- Weight and dimensions of the shipment
- Freight class (if you know it)
- Any special requirements (liftgate, inside delivery, appointment delivery)
The more detail you provide, the tighter the quote. Vague quotes get padded because the carrier assumes the worst case. If you are moving freight regularly on the same lanes, ask about contract pricing through our freight services — you will get a locked rate that holds regardless of spot market swings.
For a broader guide on how freight shipping works end to end — from booking to delivery — our freight shipping guide walks through the process step by step.
Ready to get a per-mile rate for your next shipment? Contact SeaSound Transport with your shipment details and we will provide a quote based on current lane rates and fuel prices.