Fuel Cost Calculator
Enter trip distance, your vehicle's fuel efficiency (MPG or L/100km), and current fuel price to calculate the cost of any journey. Supports annual commute cost calculation and both imperial and metric units.
How to Calculate Fuel Cost
The fuel cost formula depends on whether your vehicle's efficiency is expressed in miles per gallon (MPG, used in the US) or liters per 100 kilometers (L/100km, used in most of the rest of the world).
Imperial formula (MPG):
Metric formula (L/100km):
Tips to Improve Fuel Economy
Maintain proper tire pressure. Under-inflated tires increase rolling resistance. The US Department of Energy estimates that tires inflated 10 PSI below recommended reduce fuel economy by about 0.2% per PSI — roughly 2% total. At $3.50/ gallon over 15,000 miles, that costs about $30/year. Check tire pressure monthly (when cold, before driving).
Drive at moderate highway speeds. Aerodynamic drag increases with the square of speed. At 70 MPH a vehicle uses approximately 10–15% more fuel than at 60 MPH. The optimal speed for fuel economy for most vehicles is 45–55 MPH. Each 5 MPH above 50 MPH reduces fuel economy by approximately 7–14% depending on the vehicle.
Avoid aggressive acceleration and braking. Smooth acceleration and coasting to decelerate can improve fuel economy 10–40% in city driving according to EPA data. Anticipate traffic flow — if a red light is ahead, lift off the gas early and let the vehicle coast rather than braking hard at the last moment.
Reduce AC usage where practical. Air conditioning can reduce fuel economy 5–25% in city driving, particularly for smaller vehicles. At highway speeds above 45–50 MPH, using the AC is more efficient than opening windows (which increases aerodynamic drag). Below that speed, open windows are more efficient.
Remove excess weight. Every 100 pounds of extra weight reduces fuel economy by about 1% for the average car. Clear out cargo that is not needed for the trip. Roof racks and cargo carriers increase drag and weight — remove them when not in use (a roof cargo box can reduce highway fuel economy by 10–25%).
Average Fuel Economy by Vehicle Type
The following figures are approximate US EPA combined fuel economy ratings for typical vehicles in each category as of 2024–2025. Individual models vary significantly — always check the EPA window sticker (fueleconomy.gov) for your specific vehicle.
| Vehicle Type | Typical MPG (combined) | L/100km (approx.) |
|---|---|---|
| Small gasoline car (e.g., Toyota Corolla) | 32–36 MPG | 6.5–7.4 |
| Mid-size sedan (e.g., Honda Accord) | 28–32 MPG | 7.4–8.4 |
| Compact SUV (e.g., Honda CR-V) | 26–30 MPG | 7.8–9.1 |
| Mid-size SUV (e.g., Ford Explorer) | 20–26 MPG | 9.1–11.8 |
| Full-size pickup truck | 16–22 MPG | 10.7–14.7 |
| Hybrid car (e.g., Toyota Prius) | 48–57 MPG | 4.1–4.9 |
| Hybrid SUV (e.g., Toyota RAV4 Hybrid) | 38–41 MPG | 5.7–6.2 |
| Plug-in hybrid (PHEV, electric range) | 100+ MPGe (electric) / 30–40 MPG (gas) | varies |
| Electric vehicle (EV) | 90–140 MPGe equivalent | 2–4 L equivalent |
| Large SUV / minivan | 18–24 MPG | 9.8–13.1 |
Frequently Asked Questions
Is an EV cheaper to run than a gasoline car?
For most drivers, yes — electricity costs significantly less than gasoline per mile driven. At the US average electricity price of around $0.16/kWh and an EV efficiency of 3.5 miles/kWh, the fuel cost is about $0.046 per mile. A gasoline car averaging 30 MPG at $3.50/gallon costs $0.117 per mile — roughly 2.5 times more. The exact break-even depends on your local electricity rate, gasoline price, and how much you drive. High electricity rates (California, Hawaii) narrow the gap; low gasoline prices do the same. Charging at home off-peak hours typically costs far less than DC fast charging, which approaches gasoline costs in some markets.
What is the difference between highway and city fuel economy?
Highway fuel economy is typically 20–35% better than city fuel economy for gasoline vehicles. In city driving, frequent stopping and starting wastes energy as kinetic energy is lost to braking. Engines also operate inefficiently at low speeds and during idling. On the highway, the engine runs at a steady, more efficient RPM range. The EPA window sticker shows separate city and highway estimates, plus a combined figure (55% city / 45% highway weighted average). For hybrids, the gap reverses — hybrids recover energy through regenerative braking and often achieve better fuel economy in the city than on the highway.
What is the difference between diesel and petrol fuel efficiency?
Diesel fuel contains about 10–15% more energy per gallon than gasoline (petrol). Diesel engines also have higher compression ratios, which convert more of that energy into work rather than heat. The result is that diesel vehicles typically achieve 25–30% better fuel economy than equivalent gasoline vehicles. However, diesel fuel often costs more than gasoline, and diesel engines have higher purchase costs. Diesel vehicles are particularly cost-effective for high-mileage drivers (especially on motorways/highways) but are declining in popularity for passenger cars due to stricter emissions regulations in Europe and California.
How do I convert MPG to L/100km?
To convert miles per gallon (US MPG) to liters per 100 kilometers (L/100km): divide 235.214 by the MPG value. For example, 30 MPG = 235.214 ÷ 30 = 7.84 L/100km. To convert the other direction: divide 235.214 by the L/100km value. Example: 8 L/100km = 235.214 ÷ 8 = 29.4 MPG. Note that UK (Imperial) MPG uses a larger gallon (4.546 liters vs the US gallon of 3.785 liters), so 40 UK MPG is only about 33.3 US MPG. The conversion constant for UK MPG to L/100km is 282.48.
How much does a long commute really cost per year?
Commuting costs add up quickly. At $3.50/gallon and 28 MPG, a 30-mile round-trip commute (15 miles each way) costs about $3.75/day. Over 250 working days, that is $937/year in fuel alone. Add oil changes, tire wear, and increased depreciation from higher mileage — the IRS mileage rate of $0.67/mile for 2024 covers all driving costs — and that commute costs roughly $5,025/year total (30 miles × 250 days × $0.67). A hybrid achieving 50 MPG would cut the fuel portion to $525/year, saving $412 in fuel. These calculations make a strong case for remote work negotiations, carpooling, or housing location decisions.
Related Calculators
- EV vs Petrol Calculator — 10-year total cost of ownership comparison between electric and gasoline vehicles