Calculate diesel cost per trip, per month and per year for one truck or a whole fleet.
How this calculator works
Fuel cost is miles divided by MPG, multiplied by the price per gallon. The calculator scales that from a single trip up to monthly and annual fleet totals, and also shows your fuel cost per mile, which is the figure to plug into rate and cost-per-mile calculations.
Current diesel prices
The default price follows the EIA weekly national average for on-highway diesel, which reached record levels in September 2026 at nearly $6.00 per gallon. Regional variation is large: West Coast prices routinely run well above the Gulf Coast, so use a price that reflects your lanes. ATRI's cost research shows fuel has recently averaged around 48 cents per mile for the industry, roughly a fifth of total operating cost, but at 2026 prices that share rises quickly.
Reducing fuel spend
The three biggest levers are fuel economy (speed management, idle reduction, tire pressure and aerodynamics), buying price (fuel cards with per-gallon discounts and choosing the right stations), and route efficiency (fewer deadhead and out-of-route miles). A fuel card alone can be worth 3 to 50 cents per gallon depending on the network: see our fuel card comparison for the current options, and use our fuel card savings calculator to model the effect on your fleet.
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