Trip fuel cost depends on three numbers: distance, vehicle efficiency, and current fuel price. The fuel cost calculator below converts all three into a per-trip total in seconds — with MPG-US, MPG-UK, and L/100km support so you get the right answer whether you're driving a Ford F-150, a Toyota Prius, or a Land Rover Defender in the UK.

What This Fuel Cost Calculator Does

The fuel cost calculator answers a single practical question: "How much will the gas cost for this trip?" You enter the trip distance and the fuel efficiency of your vehicle. The calculator then converts everything into a single currency amount, displayed in your local fueling unit (gallons-US, gallons-UK, or liters).

The calculator handles three real-world situations that other online tools skip:

1. You know MPG but the gas station charges per gallon. US fuel economy ratings are reported in MPG, but you might be comparing a European vehicle or filling up with imperial gallons. The calculator accepts MPG-US and MPG-UK and converts both internally.
2. You know L/100km but your trip is in miles. Most countries outside the US use L/100km (liters per 100 kilometers). The calculator accepts L/100km and accepts your trip distance in kilometers or miles.
3. You want cost per km / cost per mile. Beyond the total, the calculator shows cost per kilometer and cost per mile so you can compare vehicles or compare against rideshare pricing.

Fuel Cost Formula

The core calculation is straightforward:

Trip cost = (distance / efficiency) × price per fuel unit

Where:

• distance = trip length in miles or kilometers
• efficiency = vehicle fuel consumption (MPG, L/100km)
• price = current fuel price per gallon (US/UK) or per liter

The calculator converts everything to liters needed × price per liter internally for accuracy, regardless of how you entered the values. This avoids rounding errors that compound when converting miles → km → MPG → liters.

Unit Conversion Reference Table

How to Use the Fuel Cost Calculator

The calculator is browser-based, so nothing leaves your computer — no signup, no upload, no tracking.

Step 1: Choose your efficiency unit. Click MPG (US), MPG (UK), or L/100 km depending on what your vehicle's manual lists.

Step 2: Enter your trip distance. For a 350-mile US road trip, enter 350. For a 600 km European journey, enter 600. Otherwise convert first.

Step 3: Enter your vehicle's fuel efficiency.

• US passenger car: 25–35 MPG-US
• US pickup truck: 15–20 MPG-US
• European compact: 5–7 L/100km
• UK SUV: 8–10 L/100km

Step 4: Enter the fuel price. Use the current pump price. Toggle between Gallon (US), Gallon (UK), or Liter using the second unit selector.

Step 5: (Optional) Enter tank capacity. If you provide tank capacity, the calculator also shows your estimated full-tank range so you can decide whether to stop mid-trip.

Step 6: Click Calculate Fuel Cost. The results card shows total trip cost, liters needed, US gallons equivalent, cost per km, and cost per mile.

Worked Examples

Example 1: 350-mile US Road Trip

• Distance: 350 miles
• Efficiency: 28 MPG-US (typical mid-size sedan)
• Price: $3.85/gallon (US)
• Result: $48.13 total, 12.5 gallons, $0.137/mile, $0.085/km

Example 2: 600 km European Trip

• Distance: 600 kilometers
• Efficiency: 6.5 L/100km (typical European diesel)
• Price: €1.65/liter
• Result: €64.35 total, 39 liters needed, 10.3 US gallons

Example 3: Family UK Holiday Drive

• Distance: 280 miles
• Efficiency: 38 MPG-UK (modern estate car)
• Price: £1.65/UK gallon
• Result: £12.16 total, 7.4 UK gallons, 33.3 liters

Example 4: Comparing Two Vehicles

Use the calculator twice — once per vehicle — to compare the actual trip cost difference for the same journey. A 5 MPG difference on a 500-mile trip is roughly $70.

Cost Per Mile vs Cost Per Km

For frequent drivers, the most useful number is cost per mile (or per km). The calculator displays both. Knowing your cost per mile helps you:

• Compare against rideshare (Uber/Lyft typically costs $1.50–2.50/mile total, of which fuel is roughly $0.10–0.20)
• Calculate IRS mileage deduction reimbursement (2024 standard rate is 67¢/mile)
• Compare against public transit costs
• Budget monthly driving costs when you know your annual mileage

Average Cost Per Mile by Vehicle Type (US Data, 2024)

Common Pitfalls and Edge Cases

Pitfall 1: Using MPG and UK gallons interchangeably. The single biggest calculator error is plugging a US-MPG figure into a UK-gallon price. The conversion: 1 MPG-US = 0.8327 MPG-UK. If your car does 30 MPG-US, it does roughly 25 MPG-UK. Use the unit toggles to avoid this.

Pitfall 2: Forgetting that efficiency ratings are optimistic. EPA tests run on a dyno under ideal conditions. Real-world MPG is typically 10–20% lower than the sticker. If your sticker says 32 MPG, budget for 26–28.

Pitfall 3: Including only highway or only city. The combined MPG figure is most useful for mixed trips. Pure highway trips will be 10–15% better; pure city trips 15–25% worse.

Pitfall 4: Ignoring tire, load, and weather effects. Roof racks, low tire pressure, headwinds, and AC usage can each reduce fuel economy by 5–10%. Winter driving reduces economy by 10–20%.

Regional Pricing Variations (2024 data)

Fuel prices vary dramatically by country and even by state/region. The prices below are typical pump prices in mid-2024: