Estimate Road Trip Fuel Costs: A Simple, Reliable Method

Set a realistic budget before you go. With a few inputs, you can estimate fuel cost within a reasonable margin and avoid surprises.

Start with the Fuel Cost Calculator at /other/fuel-cost-calculator, then refine using the adjustments below.

Core Inputs

• Distance: Total miles (include detours and side trips when possible).
• MPG: Use your real‑world average for similar trips (highway vs city mix).
• Fuel price: Use current prices for states/regions you’ll cross.

Baseline Formula

• Gallons = Distance ÷ MPG
• Cost = Gallons × Price per gallon

Example: 850 miles at 30 MPG with $3.80/gal → (850/30) × 3.80 ≈ $107.67

Adjustments for Accuracy

• Speed and terrain: High speeds, mountains, and heavy winds reduce MPG—drop MPG by 5–15% for challenging routes.
• Load and aerodynamics: Roof boxes/racks and heavy cargo can reduce MPG 5–20% on highways.
• Air conditioning: Minor city impact; on highways, AC may be better than windows down.

Planning Refuel Stops

• Identify cheaper clusters on your route and plan windows rather than exact stations.
• Keep at least 50–70 miles in reserve on rural stretches.

Buffering the Budget

• Add 10–15% contingency for traffic, detours, and price swings.
• If prices vary widely between states, bias fill‑ups toward cheaper regions.

FAQs

How do I adjust for towing or a roof rack? Lower your expected MPG before computing. For towing a small trailer at highway speeds, subtract 10–25% depending on weight and aerodynamics.