How Is Trip and Commuting Fuel Cost Calculated?
Trip fuel expenses depend directly upon three mathematical variables: total travel distance, your vehicle's real-world fuel economy (MPG or L/100km), and the local unit fuel price ($/gallon or $/liter).
1. US Imperial Fuel Expense Formulas
Gallons Consumed
Gallons =
Distance (miles)Fuel Economy (MPG)
Cost Per Mile
Cost/Mile =
Gas Price ($/gal)Fuel Economy (MPG)
2. Metric Fuel Consumption Formula
Liters Consumed=
Distance (km) × L/100km100
Step-by-Step Calculation Breakdown
Step 1: Determine Fuel Volume Consumed (300 Miles @ 25 MPG)
Fuel Consumed=
300 miles25 MPG
=12.00 gallonsStep 2: Calculate Trip Total Fuel Cost ($3.50 / Gallon)
Trip Cost=12.00 gallons × $3.50/gal=$42.00
Step 3: Calculate Cost Per Mile & Annualized Commute (10 trips/wk × 50 wks)
• Cost per Mile = $42.00 ÷ 300 miles = $0.140 / mile
• Weekly Commute (10 trips) = $42.00 × 10 = $420.00 / week
• Annual Commute (50 weeks) = $420.00 × 50 = $21,000 / year
Vehicle Class Annual Fuel Expense Comparison (15,000 Miles/Year @ $3.50/gal)
| Vehicle Category | Avg Combined MPG | Gallons / Year | Annual Fuel Cost | 5-Year Fuel Expenditure |
|---|---|---|---|---|
| Hybrid Electric (e.g. Prius, Camry Hybrid) | 52 MPG | 288 gal | $1,010 | $5,050 (Lowest gasoline cost) |
| Compact Sedan (e.g. Civic, Corolla) | 35 MPG | 429 gal | $1,500 | $7,500 |
| Mid-Size Crossover SUV (e.g. RAV4, CR-V) | 28 MPG | 536 gal | $1,875 | $9,375 |
| Full-Size Pickup / 3-Row SUV (e.g. F-150, Tahoe) | 18 MPG | 833 gal | $2,917 | $14,585 (+$9,535 vs Hybrid) |
Highway Speed vs. Aerodynamic Drag & Fuel Consumption
| Cruising Speed | Relative Efficiency | Fuel Penalty / Cost Impact |
|---|---|---|
| 55 mph (88 km/h) | 100% (Optimal) | Peak aerodynamic efficiency for most internal combustion gearings. |
| 65 mph (105 km/h) | ~92% (-8%) | Costs approx. $0.28 more per gallon equivalent. |
| 75 mph (120 km/h) | ~82% (-18%) | Drag quadruples with velocity squared; significant penalty. |
| 80 mph (130 km/h) | ~72% (-28%) | Consumes ~28% more fuel than driving at 55 mph. |