Fuel Cost Calculator

About this tool

Fuel costs are often the largest variable expense for road trips and daily commuting. Our Fuel Cost Calculator helps you accurately estimate how much you'll spend on gas based on your trip distance, vehicle's fuel efficiency (MPG or L/100km), and current fuel prices. This is essential for budgeting road trips, comparing vehicle operating costs, deciding between driving and flying, or tracking business mileage expenses. The calculator works with both U.S. units (miles, MPG, gallons) and metric units (kilometers, L/100km, liters) for international users.

Understanding fuel economy is key to managing transportation costs. MPG (Miles Per Gallon) indicates how far your vehicle travels on one gallon of gas - higher is better. A car getting 30 MPG uses half as much fuel as one getting 15 MPG for the same distance. For a 300-mile trip: 30 MPG uses 10 gallons while 15 MPG uses 20 gallons. At $3.50/gallon, that's $35 vs $70 - doubling your fuel cost. European/metric systems use L/100km (liters per 100 kilometers) where lower is better. Our calculator handles both systems and performs conversions automatically.

Many factors affect real-world fuel economy beyond the EPA estimates: highway vs city driving (highway is typically 20-30% more efficient), driving speed (55 mph is optimal; 75+ mph decreases efficiency 15-25%), weather conditions (A/C use reduces efficiency 10-20%), vehicle load and cargo, tire pressure (underinflated tires reduce MPG 3-5%), aggressive acceleration and braking, and vehicle maintenance (dirty air filters, old spark plugs reduce efficiency). The EPA estimates on your window sticker are tested in ideal conditions. Real-world MPG is often 10-20% lower, so budget conservatively.

The calculator is also valuable for comparing vehicles before purchase. If deciding between a $30,000 sedan (35 MPG) and a $28,000 SUV (22 MPG), calculate long-term fuel costs. Driving 15,000 miles/year at $3.50/gallon: sedan costs $1,500/year in gas, SUV costs $2,386/year. Over 5 years, the SUV costs $4,430 more in fuel, negating its lower purchase price. For business use, IRS allows standard mileage deduction (65.5¢/mile in 2023) covering fuel, depreciation, and maintenance. Our calculator helps determine if actual costs exceed this rate. All calculations are performed privately in your browser with no data stored.

Usage examples

Fuel needed: 450 ÷ 28 = 16.07 gallons. Total cost: 16.07 × $3.45 = $55.45. Cost per mile: $55.45 ÷ 450 = $0.123/mile. For a family of 4, that's $13.86 per person. Compare to flying: 4 tickets at $150 = $600. Driving saves $544.55 but takes more time. Budget additional $20-30 for snacks/tolls during drive.

Annual distance: 30 × 250 = 7,500 miles. Fuel needed: 7,500 ÷ 24 = 312.5 gallons. Annual fuel cost: 312.5 × $3.80 = $1,187.50. Monthly: $98.96. This doesn't include maintenance, insurance, depreciation. IRS standard rate (65.5¢/mile) would reimburse $4,912.50, covering all vehicle costs. Compare to public transit pass at $100/month ($1,200/year) for similar cost without wear on your vehicle.

Sedan: 2,000 ÷ 38 = 52.63 gallons × $3.60 = $189.47. SUV: 2,000 ÷ 21 = 95.24 gallons × $3.60 = $342.86. Difference: $153.39 savings with sedan. However, if you need SUV space for camping gear and 6 people, the $25.57 per person extra might be worth the convenience. Alternatively, rent fuel-efficient vehicle for $50/day × 10 days = $500 (still expensive but new, reliable vehicle).

Fuel needed: 850 ÷ 10 = 85 gallons. Total cost: 85 × $4.20 = $357. Add truck rental ($150-200/day × 3 days = $450-600). Total moving cost: $807-957 for DIY move. Professional movers quote $2,500. DIY saves $1,543-1,693 but requires physical labor and time. Factor in helpers' pizza/beer budget ($100) and potential injury risk.

Gas car: 12,000 ÷ 28 = 428.57 gallons × $3.50 = $1,500/year. Electric car: 12,000 ÷ 3.5 = 3,428.57 kWh × $0.13 = $445.71/year. Savings: $1,054.29 annually. Over 6 years (typical ownership): $6,325.68 savings. This helps offset higher EV purchase price. Add savings on oil changes ($300/year) and brake maintenance ($200/year): total savings $9,325.68 over 6 years. Break-even if EV costs $9,000 more.

How to use

1. Enter your trip distance in miles or kilometers
2. Input your vehicle's fuel efficiency (MPG or L/100km)
3. Enter the current fuel price per gallon or liter
4. Select your measurement units (US or metric)
5. Click "Calculate" to see total fuel cost
6. Review gallons/liters of fuel needed
7. See cost per mile or kilometer for your trip
8. Compare different vehicles using the same route
9. Plan round-trip costs by doubling the distance
10. Factor in multiple stops or detours by adding extra miles

Benefits

• Calculate exact fuel costs for any trip distance
• Supports both US (MPG, gallons) and metric (L/100km, liters) units
• Compare fuel costs between different vehicles
• Plan road trip budgets with accurate fuel estimates
• See cost per mile/kilometer for expense tracking
• Helps decide between driving and alternative transportation
• Useful for business mileage and reimbursement calculations
• Estimate annual commuting fuel expenses
• Compare gas vs electric vehicle operating costs
• No registration or personal data required
• Instant calculations on any device
• Free forever with unlimited calculations

FAQs