Washington IFTA Calculator

Washington State has the highest diesel tax rate in the Pacific Northwest at $0.494 per gallon, driven by a progressive transportation funding model. The state is a gateway for Pacific Rim trade through the Port of Seattle and the Port of Tacoma — together, these ports form the Puget Sound Maritime Center, one of the top container port complexes in North America. I-5 runs north-south from the Oregon border through Portland (Oregon), Olympia, Tacoma, Seattle, and Everett to the Canadian border at Blaine. I-90 runs east-west from Seattle through the Cascade Mountains via Snoqualmie Pass to Spokane and the Idaho border. I-82 connects the Yakima Valley wine and agricultural region to the Tri-Cities and I-84 in Oregon.

Washington's rate of $0.494 makes it one of the more expensive fueling states in the West. Oregon at $0.380 to the south is cheaper. Idaho at $0.320 to the east is significantly cheaper. If your route takes you into Idaho before Washington — eastbound I-90 toward Spokane — consider whether you can top off in Idaho before returning into Washington for your next load.

The Snoqualmie Pass on I-90 is subject to chain requirements and closures from November through March. The North Cascades Highway (SR-20) is closed in winter entirely. Snoqualmie Pass closures affect the primary route between Seattle and eastern Washington and can reroute freight through Yakima on US-12 or through Stevens Pass on US-2 — neither of which are ideal for heavy commercial vehicles.

Standard weight limits are 80,000 lbs. Washington has a significant agricultural inspection program — agricultural inspection stations operate at the Oregon border and at the Idaho border to check for invasive species in incoming loads. For IFTA compliance, Washington's DOL handles IFTA through an online system — with a high rate, any significant Washington mileage will generate meaningful tax liability, so accurate odometer logging is essential on all Washington routes.