Oregon Weight-Mile Tax Explained for Trucking Companies

Jan. 9, 2026, 4:32 p.m.
Oregon is one of the few states that does not charge a standard fuel tax on diesel for heavy trucks. Instead, it uses the Oregon Weight-Mile Tax (WMT)—a system that taxes trucks based on how much they weigh and how many miles they travel in the state. Understanding WMT is critical for avoiding fines, delays at weigh stations, and audit issues.
Oregon Weight-Mile Tax

What Is the Oregon Weight-Mile Tax?

The Oregon Weight-Mile Tax is a highway use tax that applies to commercial vehicles operating in Oregon that weigh 26,001 pounds or more.

Instead of paying diesel fuel tax at the pump, qualifying vehicles must:

  • Report miles traveled in Oregon

  • Pay tax based on declared weight and axle configuration

This system is administered by the Oregon Department of Transportation (ODOT).

 Who Must Pay Oregon Weight-Mile Tax?

You must comply with WMT if your vehicle:

  • Has a GVW or combined weight of 26,001 lbs or more

  • Operates on public roads in Oregon

  • Is registered under IRP or operating on a trip permit

This applies to:

  • In-state carriers

  • Out-of-state carriers

  • Owner-operators

  • Private and for-hire fleets

 Who Is Exempt?

Some vehicles are exempt or partially exempt, including:

  • Government-owned vehicles

  • Certain agricultural vehicles (limited cases)

  • Light vehicles under 26,001 lbs

 Exemptions are limited and strictly enforced.

 How Oregon Weight-Mile Tax Is Calculated

Your WMT amount depends on three main factors:

1. Declared Weight

Higher registered or operating weight = higher tax rate.

2. Axle Configuration

More axles usually mean a lower per-mile rate, as weight is distributed.

3. Miles Traveled in Oregon

Only Oregon miles are taxable.

 Rates are set by ODOT and change periodically.

 Ways to Comply with Oregon WMT

Option 1: Enroll in Oregon Weight-Mile Tax Program, call to (503) 386-4187

  • File monthly mileage reports

  • Pay tax based on actual miles driven

  • Best for carriers operating regularly in Oregon

Option 2: Purchase a Weight-Mile Tax Trip Permit, at https://www.oregontruckingonline.org/

  • Used for temporary or occasional operations

  • Covers a specific time period or trip

  • Common for out-of-state carriers

 Weight-Mile Tax vs IFTA (Key Difference)

Feature Oregon WMT IFTA
Tax Type Mileage-based Fuel-based
Applies in Oregon  Yes  No diesel tax
Reporting Monthly or per trip Quarterly
Based on Weight + miles Fuel used

 IFTA does not replace Oregon Weight-Mile Tax. You must comply with both if applicable.

 Enforcement & Penalties

ODOT enforces WMT at:

  • Weigh stations

  • Ports of entry

  • Roadside inspections

Violations may result in:

  • Fines and penalties

  • Back taxes

  • Out-of-service orders

  • Account audits

 Required Records

Carriers must keep:

  • Mileage logs

  • Trip records

  • Permits and credentials

  • Weight declarations

Records must typically be kept for at least 3 years.

 Best Practices for Trucking Companies

 Declare accurate operating weight
 Track Oregon miles separately
 File reports on time
 Purchase trip permits when needed
 Keep documentation accessible in the cab

 Key Takeaways

  • Oregon uses Weight-Mile Tax instead of diesel fuel tax

  • Applies to vehicles 26,001 lbs and above

  • Tax is based on weight, axles, and miles

  • Out-of-state carriers are not exempt

  • Compliance is strictly enforced

If you want, I can:

  • Create a WMT checklist

  • Design a horizontal header image

  • Write a step-by-step compliance guide

  • Compare Oregon WMT vs New Mexico WDT

 

Oregon Weight-Mile Tax