Trip Fuel Cost Calculator
Estimate the total fuel cost for any road trip by entering your trip distance, vehicle's fuel economy, and local gas price. Perfect for budgeting before a long drive.
About this calculator
The cost to fuel a road trip depends on three factors: how far you drive, how efficiently your vehicle uses fuel, and what you pay per gallon. The formula is: fuel cost = (distance / mpg) × gas_price. Dividing the total distance by your vehicle's miles-per-gallon rating gives the number of gallons you will consume. Multiplying that by the price per gallon yields the total dollar cost for the trip. This calculation assumes a constant MPG and gas price, so factor in variations for city driving, highway cruising, or anticipated price differences along your route. For a more accurate estimate, use the combined MPG rating from the EPA label on your vehicle.
How to use
Imagine you are driving 350 miles, your car gets 32 MPG, and gas costs $3.60 per gallon. First, calculate gallons needed: 350 / 32 = 10.94 gallons. Then multiply by gas price: 10.94 × $3.60 = $39.38. Your trip fuel cost is approximately $39.38. If you are making a round trip, simply double the distance to 700 miles and recalculate: 700 / 32 × $3.60 = $78.75 for the round journey.
Frequently asked questions
How do I find my car's MPG for an accurate fuel cost estimate?
The most reliable source is the EPA fuel economy label found on new vehicles or the fueleconomy.gov database for older models. These ratings are split into city, highway, and combined estimates — use the combined figure for mixed driving or the highway figure for mostly freeway travel. You can also calculate your real-world MPG by filling the tank, recording the odometer, driving until nearly empty, then dividing miles driven by gallons used to refill. Real-world MPG can differ from EPA estimates based on driving habits, load, and conditions.
Why does my actual fuel cost differ from the calculator's estimate?
The calculator assumes a constant MPG and a single gas price for the entire trip. In reality, fuel economy varies with speed, elevation changes, air conditioning use, vehicle load, and traffic. Gas prices also fluctuate significantly between regions and states. Stop-and-go urban driving can drop your effective MPG well below the highway rating, while steady highway cruising at moderate speeds often beats the combined estimate. For the most accurate result, use a segmented approach: calculate city and highway portions separately.
What is a good MPG for a road trip and how does it affect total cost?
For road trips, most modern sedans achieve 30–40 MPG on the highway, while SUVs typically range from 22–30 MPG and trucks from 15–22 MPG. The difference in fuel cost between a 25 MPG SUV and a 35 MPG sedan over a 500-mile trip at $3.50/gallon is significant: $70 versus $50 — a $20 savings. Hybrids and EVs (converted to MPGe) can push efficiency even higher. Choosing a more fuel-efficient vehicle or reducing highway speed by 5–10 mph can meaningfully reduce trip costs.