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FuelCostCalculator

Q: How to calculate fuel cost for a road trip?

Multiply the trip distance by your car's fuel consumption to get fuel needed, then multiply by the fuel price. In metric: Fuel (L) = Distance (km) × L/100km ÷ 100, and Cost = Fuel (L) × price per liter. In imperial: Fuel (gal) = Distance (mi) ÷ MPG, and Cost = Fuel (gal) × price per gallon. Double the distance for a round trip, and divide the total by the number of people to split it.

Q: How to convert MPG to L/100km?

Divide 235.215 by the US MPG value to get L/100km (for example 30 US MPG = 7.84 L/100km). For UK (imperial) MPG divide 282.481 by the MPG value. The conversion works in reverse too: US MPG = 235.215 ÷ L/100km.

Q: How do I split the gas bill between passengers?

Calculate the total trip cost (fuel plus any tolls or parking), then divide by the number of people sharing the ride, including the driver. FuelCostCalculator does this automatically with the passengers selector.

Q: What is the difference between US MPG and UK MPG?

A US gallon is 3.785 liters while a UK (imperial) gallon is 4.546 liters. Because the UK gallon is about 20% larger, the same car shows a higher MPG figure in the UK than in the US.

Q: What are the best tips for improving fuel efficiency on long drives?

Keep a steady moderate speed (around 80–100 km/h or 50–60 mph), use cruise control on highways, keep tires correctly inflated, remove roof boxes and extra weight, avoid hard acceleration and braking, limit idling, and use air conditioning sparingly at low speeds.

Q: Is FuelCostCalculator free and private?

Yes. It is 100% free and runs entirely in your web browser. No sign-up is needed and no trip data is sent to any server.

100% Free, Browser-Based Trip Gas Cost & Fuel Efficiency Calculator.

Quick vehicle presets

Trip distance

Round trip (×2 distance)

Fuel efficiency

L/100km

Fuel price

/ L

Split cost between people incl. driver

Extra trip costs (tolls, parking, vignette — optional)

Tolls & vignettes

Parking & other

Extras are added once to the total (not doubled for round trips) and included in the per-person split.

Fuel Efficiency Converter: MPG ↔ L/100km ↔ km/L

Type in any box — the others update instantly.

L/100km km/L MPG (US) MPG (UK)

Common conversions
L/100km	km/L	MPG (US)	MPG (UK)

How to Calculate Fuel Cost for a Road Trip

Estimating gas money before a trip takes three numbers: distance, your vehicle's fuel consumption, and the fuel price. FuelCostCalculator combines them instantly and handles every unit conversion for you.

Metric formula (km, L/100km)

Fuel (L) = Distance (km) × L/100km ÷ 100
Cost = Fuel (L) × Price per L

Example: 450 km at 6.5 L/100km = 29.25 L. At €1.75/L the trip costs €51.19.

Imperial formula (miles, MPG)

Fuel (gal) = Distance (mi) ÷ MPG
Cost = Fuel (gal) × Price per gal

Example: 300 miles at 30 MPG = 10 gallons. At $3.50/gal the trip costs $35.00.

Step-by-step

Enter the one-way distance from your map app and choose km or miles.
Enter your car's consumption from the trip computer or spec sheet (L/100km, km/L, US MPG or UK MPG).
Enter the local fuel price and choose whether it's per liter or per gallon, plus your currency.
Turn on Round trip if you're driving back the same way.
Set how many people share the ride to see each person's share of the gas bill.
Add tolls or parking if you want the full trip cost, then copy or share the summary.

How to Convert MPG to L/100km

MPG measures distance per fuel; L/100km measures fuel per distance, so they're inversely related. Use L/100km = 235.215 ÷ US MPG or L/100km = 282.481 ÷ UK MPG. For example, 40 US MPG ≈ 5.88 L/100km, and 8 L/100km ≈ 29.4 US MPG. Use the converter above for any value.

Tips for Improving Fuel Efficiency on Long Drives

Hold a steady speedMost cars are most efficient around 80–100 km/h (50–60 mph). Above that, drag rises sharply.
Use cruise controlOn flat highways it smooths out speed changes that waste fuel.
Check tire pressureUnder-inflated tires increase rolling resistance. Inflate to the door-jamb spec when cold.
Cut weight & dragRemove empty roof boxes and bike racks, and don't haul unnecessary cargo.
Drive smoothlyGentle acceleration and anticipating stops can save a noticeable share of fuel.
Limit idling & A/C at low speedSwitch off during long stops; at highway speed, closed windows with A/C beat open windows.

Typical Fuel Consumption by Vehicle Type

Vehicle	L/100km	US MPG
Hybrid compact	4.0 – 5.0	47 – 59
Small hatchback	5.0 – 6.5	36 – 47
Mid-size sedan	6.5 – 8.0	29 – 36
SUV / crossover	8.0 – 11.0	21 – 29
Pickup / van	11.0 – 15.0	16 – 21

Typical ranges for highway-weighted driving; your real-world figure depends on speed, load, weather and terrain.

Frequently Asked Questions

How to calculate fuel cost for a road trip?

Multiply distance by consumption to get fuel needed, then multiply by fuel price. Metric: Fuel (L) = km × L/100km ÷ 100. Imperial: Fuel (gal) = miles ÷ MPG. Double the distance for a round trip and divide by the number of people to split it.

How to convert MPG to L/100km?

Divide 235.215 by US MPG (or 282.481 by UK MPG). 30 US MPG = 7.84 L/100km. The formula is symmetrical: US MPG = 235.215 ÷ L/100km.

How do I split the gas bill between passengers?

Add up fuel plus tolls and parking, then divide by everyone sharing the ride, including the driver. Set the "Split cost between" selector and copy the summary to send it to your group chat.

What is the difference between US MPG and UK MPG?

A US gallon is 3.785 L; a UK (imperial) gallon is 4.546 L. Since the UK gallon is about 20% bigger, the same car reports a higher MPG in the UK. Always match the MPG type to where the figure came from.

What are the best tips for improving fuel efficiency on long drives?

Drive at a steady moderate speed, use cruise control, keep tires properly inflated, remove roof boxes and extra weight, accelerate gently, avoid long idling and use A/C sparingly at low speeds.

Is FuelCostCalculator free and private?

Yes — completely free, no sign-up, and every calculation runs locally in your browser. No trip data is sent to a server.