About the Fuel Cost Calculator
This fuel cost calculator tells you how much fuel a trip will burn and what it will cost at the pump. Enter the distance, your vehicle’s fuel economy and the current price of fuel, and it returns the trip cost, the fuel needed, the cost per mile (or kilometre) and — if you are sharing the ride — what each passenger owes. It works in US units (miles, MPG, price per gallon) or metric units (kilometres, litres per 100 km, price per litre).
Use it to budget a road trip, decide whether driving beats flying or taking the train, settle a gas split with friends, or compare the running cost of two cars. The annual figure uses your typical yearly driving, so you can see how much a more efficient vehicle would save over a full year, and the chart compares your fuel bill with cars at other efficiency levels.
The result assumes your average real-world fuel economy for the whole route. Highway driving, heavy loads, roof boxes, towing, air conditioning and speeds above about 50 mph (80 km/h) all change consumption — FuelEconomy.gov notes that mileage usually drops rapidly above 50 mph and a roof cargo box can cut highway economy by 6–17%, so use the figure from your own fuel log or trip computer where you can.
With the default inputs, the trip fuel cost is $62.50. Change any value above to recalculate instantly.
How to use the fuel cost calculator
- 1Choose US or metric units.
- 2Enter the one-way trip distance and switch on round trip if you are coming back.
- 3Enter your car’s real-world fuel economy (MPG or L/100 km).
- 4Enter the current fuel price per gallon or litre and pick your currency.
- 5Set how many people are sharing the cost and your yearly mileage.
- 6Read the trip cost, per-person share and yearly fuel bill.
Formula and method
Fuel used is distance divided by miles per gallon in US units, or distance multiplied by litres per 100 km and divided by 100 in metric units. Multiplying the fuel used by the price per gallon or litre gives the trip cost; a round trip simply doubles the distance.
The cost per mile (or km) is the price divided by MPG, or the price times L/100 km ÷ 100. The yearly cost multiplies that per-distance cost by your annual driving, and the per-person figure divides the trip cost evenly between everyone sharing the ride. The calculation assumes a constant average fuel economy across the whole distance.
- Distance
- Miles or kilometres driven (doubled for a round trip)
- MPG
- Miles per gallon (US gallon)
- L/100 km
- Litres of fuel used per 100 kilometres
- Price
- Fuel price per gallon or per litre
Worked examples
500-mile road trip at 28 MPG and $3.50/gal
500 miles ÷ 28 MPG = 17.86 gallons. At $3.50 a gallon that is $62.50 for the trip, or 12.5 cents a mile. At 12,000 miles a year the same car spends about $1,500 on fuel.
Metric in euros: 800 km each way, 6.5 L/100 km, 4 people
A round trip is 1,600 km. At 6.5 L/100 km the car uses 1,600 × 6.5 ÷ 100 = 104 litres, which at €1.85 per litre costs €192.40 — €48.10 each for four people. Driving 15,000 km a year costs about €1,804 in fuel.
SUV round trip of 1,200 miles each way, split three ways
2,400 miles at 22 MPG needs 109.09 gallons. At $3.89 per gallon the fuel bill is $424.36, so each of the three travellers owes about $141.45.
Frequently asked questions
How do I calculate gas cost for a trip?+
Divide the trip distance by your car’s miles per gallon to get the gallons needed, then multiply by the price per gallon. For example, 300 miles ÷ 30 MPG = 10 gallons, and 10 × $3.50 = $35.
How do I convert MPG to L/100 km?+
Divide 235.21 by the MPG figure (US gallons). 30 MPG is about 7.8 L/100 km and 40 MPG is about 5.9 L/100 km. The MPG to L/100 km converter does this for any value.
What fuel economy should I use for a road trip?+
Use your real-world average from fuel receipts or the trip computer rather than the window sticker. Highway driving at moderate speeds is often better than the combined rating, while roof boxes, heavy loads and high speeds make it worse.
How should friends split gas on a road trip?+
The simplest fair method is to divide the total fuel cost equally among everyone in the car. If people join for only part of the trip, the gas split calculator can apportion the cost by distance travelled.
Does this include tolls, parking or wear and tear?+
No — it covers fuel only. Tolls, parking, maintenance, tyres and depreciation add to the true cost of driving; the IRS standard mileage rate or a total cost of ownership calculator gives a fuller per-mile figure.