Fuel Cost Calculator (trip cost + per-person split)
Pick metric or imperial units; enter distance, fuel efficiency, fuel price per gallon/liter, and number of passengers. Returns total cost, fuel used, cost per mile/km, and cost per person.
- Total fuel cost
- 11.67
- Fuel used
- 3.33 gal
- Cost per mi
- 0.12
How it works
How fuel cost is calculated
Three numbers fully determine fuel cost: distance, fuel efficiency, and price per unit. Fuel used = distance / efficiency. Total cost = fuel used × price.
Metric: 100 km at 12 km/L = 8.33 L. At ¥175/L = ¥1458. Imperial: 100 mi at 30 MPG = 3.33 gal. At $3.50/gal = $11.67.
Cost per distance is the most useful comparison metric — what does each km/mile actually cost? It lets you compare different vehicles or routes on the same scale.
Why split costs (carpooling)
Sharing a 200-mile road trip with 4 people: $25 fuel each, vs $100 driving alone. Carpooling is one of the highest-ROI cost-saving habits, with a typical urban commuter saving $1000-3000/year.
Splitting also reduces traffic and emissions. Many cities have carpool lanes (HOV, 高占有率車線) that bypass slower traffic — additional time savings.
Apps like Waze Carpool, BlaBlaCar, and Lyft Line / Uber Pool make ad-hoc carpooling easier. The math here works whether you split formally or just for a one-time trip with friends.
Beyond fuel: total trip cost
Fuel is one part of trip cost. Add: tolls, parking, vehicle wear (~$0.10-0.20 per mile per IRS standard), maintenance proportional to distance.
IRS 2025 standard mileage rate: $0.67/mile (covers fuel, oil, maintenance, depreciation, insurance — comprehensive vehicle cost). For a more accurate trip cost, multiply distance by this rate instead of just fuel cost.
Electric vehicles flip the equation: a 30 kWh trip at $0.15/kWh = $4.50, often less than half the fuel cost. EVs also have ~$0.05/mile lower maintenance vs gasoline, especially over many miles.
Frequently asked questions
›What's typical fuel efficiency?
Modern compact car: 30-40 MPG / 13-17 km/L. Modern sedan: 25-35 MPG / 11-15 km/L. SUV/truck: 18-28 MPG / 8-12 km/L. Hybrid: 45-55 MPG / 19-23 km/L.
›Should I use city, highway, or combined MPG?
If most of the trip is highway, use highway MPG. If urban, city MPG. For mixed, combined. Real-world results often beat EPA highway in light traffic, lag city in heavy traffic.
›Can I use this for electric vehicles?
Set efficiency to miles/kWh (typically 3-4 mi/kWh) and price to $/kWh. The math works the same; just be aware of the unit difference.
›Why is my real fuel cost higher than predicted?
Three common reasons: (1) real-world MPG is 5-15% below EPA, (2) traffic and acceleration patterns burn extra fuel, (3) cold weather reduces efficiency 10-20%. Round up the calculator's estimate by ~10% for safety.
›How does this compare for a longer trip?
Linear: 200 miles costs 2x what 100 miles cost (same MPG and price). For multi-leg trips with different fuel-up locations, calculate each leg separately.
›What about diesel vs gasoline?
Diesel cars have higher MPG (5-15% better) but diesel fuel often costs more. Net cost depends on local prices. Adjust efficiency and price; the math is the same.
›Should I include the cost of an oil change for the trip?
Standard mileage method (IRS $0.67/mi) implicitly includes maintenance prorated by distance. For per-trip explicit fuel-only, no — but track maintenance separately.
›Does the data leave my browser?
No. Calculation runs locally; nothing is sent to a server.
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