Estimate the gas cost of any road trip. Enter your distance, fuel efficiency, and gas price to get an instant estimate.
Fuel cost is typically the largest variable expense in road trip planning, and small differences in fuel efficiency, route choice, and driving behaviour can add up to significant savings over a long journey. Understanding the factors that affect fuel consumption helps you budget accurately and drive more economically.
What affects fuel consumption: Speed is the biggest factor — aerodynamic drag increases with the square of velocity, meaning driving at 80 mph uses roughly 25% more fuel than 60 mph. Air conditioning adds 5–25% to fuel consumption, particularly in city driving. Cold weather increases fuel use as engines require more fuel to reach operating temperature and batteries (in hybrid/EVs) operate less efficiently. Tyre pressure affects rolling resistance — tyres underinflated by just 10 PSI reduce fuel economy by 1–2 MPG. Roof racks and cargo carriers add aerodynamic drag even when empty.
Hypermiling techniques for long trips: "Hypermiling" refers to driving techniques that maximise fuel efficiency. The most effective techniques include maintaining steady speed on highways using cruise control, anticipating traffic flow to avoid hard braking and acceleration, coasting to stops rather than braking at the last moment, and using engine braking on descents rather than riding the brakes. Experienced hypermilers report achieving 20–40% above EPA-rated fuel economy on long highway drives using these techniques.
Gas station strategies for long trips: Fuel prices can vary by 20–30 cents per gallon across different stations in the same metro area, and by even more between states. Apps like GasBuddy and Waze show real-time prices at nearby stations. For interstate highway driving, avoid gas stations at major interchange exits where prices are typically 5–15 cents higher due to captive audience pricing; prices at stations a mile or two off the highway are usually lower. It is also worth noting that filling up with slightly less than a full tank reduces the weight you are carrying, though this effect is minor (a gallon of gasoline weighs about 6 lbs).
Comparing gas vs electric for long trips: An electric vehicle with a 300-mile range and $0.15/kWh electricity charging rate costs approximately $12–18 to travel 300 miles (30–40 kWh at 7.5–9 miles/kWh). A 30 MPG gas car at $3.50/gallon costs $35 for the same distance. The EV is about 2.5× cheaper per mile on energy costs. However, public fast charging during road trips can be 2–4× more expensive than home charging, narrowing the cost advantage. Factor charging time into road trip planning — Level 3 DC fast chargers can add 150+ miles in 20–30 minutes at major charging networks.
Route optimisation for fuel savings: Choosing between highway and local roads involves a trade-off between speed and fuel efficiency. Modern GPS navigation apps optimise for time, but many offer a "fuel-efficient route" option that avoids stop-and-go traffic. For trips under 20 miles, the extra distance of a highway bypass may burn more fuel than sitting through occasional traffic lights on a local route. For longer trips, steady highway speed almost always beats urban driving for fuel economy.