Fuel Cost Calculator
Work out gas cost for a trip or a regular commute from distance, mpg or L/100 km and your fuel price, with tolls, parking and a per-person split.
Interactive calculator · Method FUEL-TRIP-COST-1.0 · Last reviewed: 2026-11-04
Calculate your scenario
Trip distance = one-way distance × 2 for a round trip.
Your inputs
Default worked example. Edit the inputs to calculate your scenario.
Default worked example
Fuel = 40 mi (64.3738 km) ÷ 11.904 km/L = 5.4077 L × $0.9246/L = $5.00; + $0.00 tolls and parking = $5.00 per trip; × 5 trips × 48 weeks = $1,200.00 a year.
How to use the calculator
Enter the one-way distance and choose round trip or one way, then your car's efficiency, the fuel price you pay, any tolls and parking per trip, and how many people split the cost. For a commute, add trips per week and weeks per year.
What the result means
A 20-mile commute each way is 40 miles a day; at 28 mpg and $3.50 a gallon that is about 1.43 gallons and $5.00 a day, or $1,200 over 48 five-day weeks.
Formula and units
Trip distance = one-way distance × 2 for a round trip. Fuel used = distance ÷ efficiency (mpg values are turned into km per liter with 1 mi = 1.609344 km, 1 US gal = 3.785411784 L and 1 Imperial gal = 4.54609 L; L/100 km gives liters = km × value ÷ 100). Fuel cost = liters × price per liter. Trip total = fuel cost + tolls + parking; per person = total ÷ people. Commute: weekly = trip total × trips per week; annual = weekly × weeks; monthly = annual ÷ 12.
Worked examples
20-mile commute at 28 mpg: One-way distance: 20 distance unit; Fuel efficiency: 28 efficiency unit; Fuel price (example 3.50): 3.5 $ per unit; Trips per week (commute): 5 trips; Weeks per year (commute): 48 weeks; Tolls per trip: 0 $; Parking per trip: 0 $; People sharing the cost: 1 people; Distance unit: mi; Trip: round; Efficiency unit: mpgus; Price is per: usgal; Use: commute.
Example result: Total cost per trip: $5.00; Fuel used per trip: 1.4286 US gal · 1.1895 Imp gal · 5.4077 L; Fuel cost per trip: $5.00; Cost per person per trip: $5.00; Weekly commute cost: $25.00 ($25.00 per person); Annual commute cost: $1,200.00 ($1,200.00 per person).
450 km road trip at 6.5 L/100 km for three people: One-way distance: 450 distance unit; Fuel efficiency: 6.5 efficiency unit; Fuel price (example 3.50): 1.8 $ per unit; Trips per week (commute): 5 trips; Weeks per year (commute): 48 weeks; Tolls per trip: 12 $; Parking per trip: 0 $; People sharing the cost: 3 people; Distance unit: km; Trip: oneway; Efficiency unit: l100; Price is per: l; Use: single.
Example result: Total cost per trip: $64.65; Fuel used per trip: 7.727 US gal · 6.4341 Imp gal · 29.25 L; Fuel cost per trip: $52.65; Cost per person per trip: $21.55; Weekly commute cost: not used for a single trip; Annual commute cost: not used for a single trip.
Limitations and common mistakes
You supply the distance, efficiency and price: there is no route lookup or live fuel price, and the default price is an example. Real fuel use changes with speed, traffic, load, weather and idling. Wear, insurance, depreciation and other running costs are not included. For a commute, a "trip" is what the Trip choice describes, so a daily round trip counts once per day.
Entering the round-trip distance and also choosing round trip, which doubles the cost; enter the one-way distance.
Sources and assumptions
Method FUEL-TRIP-COST-1.0; last formula review 2026-11-04. Sources and their supported claims. Calculation methodology.