How to use it
- Choose kilometers and liters or miles and US gallons.
- Enter the one-way distance and your car's average consumption.
- Add the fuel price and, if you know them, tolls and parking.
- Set how many people split the cost and whether it is a round trip.
What the road trip calculator does
A road trip feels cheap until the fuel receipts pile up. This calculator estimates the cost of a drive before you leave, from four numbers you can find easily: the distance, your car's fuel consumption, the price of fuel and the extras like tolls and parking. It shows the fuel you will need, the fuel cost, the total, the cost per kilometer or mile and how much each person pays when the cost is shared.
It works in two unit systems. In metric, the distance is in kilometers, consumption in liters per 100 km or in kilometers per liter, and the price is per liter. In US units, the distance is in miles, consumption in miles per US gallon and the price is per gallon. Choose the one your car's dashboard and your local fuel stations use.
How the fuel cost is calculated
The core of the calculation is the amount of fuel the drive will use:
- Liters per 100 km: distance multiplied by consumption, divided by 100.
- Kilometers per liter: distance divided by consumption.
- Miles per gallon: distance divided by consumption.
The fuel cost is that amount multiplied by the fuel price. Tolls and parking are added on top to get the total, and the total is divided by the number of people sharing the car. When you turn on the round trip option, the distance is doubled before everything else.
Converting between consumption units
Different countries and car manuals use different units, so it helps to know how to convert:
- From km/L to L/100 km: divide 100 by the km/L value. A car that does 12.5 km/L uses 8 L/100 km.
- From L/100 km to km/L: divide 100 by the L/100 km value.
- From US mpg to L/100 km: divide 235.2 by the mpg value. A car that does 30 mpg uses about 7.8 L/100 km.
Lower is better in liters per 100 km, while higher is better in km/L and mpg. Mixing them up is the most common mistake in fuel estimates, so double-check the unit selected in the calculator.
Two worked examples
A group of three friends plans a 400 km drive to the coast and back. Their car uses 8 liters per 100 km, fuel costs 6 per liter in their currency and tolls and parking add up to 60 for the whole trip. With the round trip turned on, the car will drive 800 km and use 64 liters of fuel. The fuel costs 384, the total with tolls is 444 and each person pays 148. The cost per kilometer is about 0.56.
In US units, a 300-mile drive in a car that does 30 miles per gallon uses 10 gallons. At 3.50 per gallon, the fuel costs 35. Those small numbers add up quickly on a week-long road trip, which is why it is worth calculating each leg.
What changes your real consumption
The consumption listed in the manual is measured in controlled conditions. On the road, several things change it:
- Speed: above about 110 km/h (70 mph), air resistance grows fast and consumption with it.
- Load: a full trunk, passengers and especially a roof box increase consumption.
- Air conditioning: it can add a noticeable amount in hot weather and city traffic.
- Terrain: mountain roads cost more fuel than flat highways.
- Traffic: stop-and-go driving is far less efficient than a steady pace.
- Tire pressure: under-inflated tires increase rolling resistance.
For long highway trips, use the highway figure of your car if you know it. For a better estimate, fill the tank, drive normally for a while and divide the distance by the fuel you put back in.
Other road trip costs
Fuel is the biggest line, but rarely the only one. Before you leave, think about:
- Tolls and vignettes, which some countries require for highways
- Parking at hotels and in city centers
- Meals and snacks on the way
- Lodging if the drive is split over more than one day
- A share of maintenance and tire wear on long trips
- Car rental, insurance and the fuel policy if the car is not yours
Add the tolls and parking to the extras field. The rest is easier to plan in a full trip budget.
Splitting the cost fairly
When friends share a car, the simplest rule is to divide fuel, tolls and parking equally among everyone in it. If one person drives their own car, some groups also add a small amount per kilometer for wear, agreed before leaving. Whatever rule you choose, decide it early and write it down. It avoids awkward conversations at the end of the trip.
Plan the stops, not only the cost
A good road trip has a plan for where to stop, eat and sleep. In the Tripyno app you can add each leg and stop as an event in the travel itinerary planner, with times and notes, and record fuel and tolls as expenses in the trip budget. Everything works offline, which helps on roads with no signal.