Gas Savings Trip Calculator
Estimate the total fuel cost of a road trip from distance, MPG, and gas price — plus gallons needed and the cost split per passenger.
How to use this tool
- Enter the trip distance (decide one-way or round-trip).
- Enter your vehicle's average MPG.
- Enter the price of gas per gallon.
- Enter how many people are splitting the cost.
- Read total cost, gallons, cost per person, and cost per mile.
Planning a road trip? Enter the distance, your car's MPG, and the price of gas to see the total fuel cost, gallons needed, and what each passenger owes.
Formula
Fuel needed and cost follow directly from distance, economy, and price:
Gallons = Distance ÷ MPG
Total cost = Gallons × Price per gallon
Cost per person = Total cost ÷ People
Cost per mile = Total cost ÷ Distance
How it works
Road-trip fuel cost is one of the cleanest calculations in driving: the miles you travel divided by your car's fuel economy gives the gallons you'll burn, and multiplying by the pump price gives the dollars. This calculator does exactly that, then splits the bill among passengers and expresses the cost per mile so you can compare routes or vehicles.
For the most accurate number, use your real-world highway MPG rather than the EPA city figure, since most trips are highway miles. Decide up front whether the distance you enter is one-way or round-trip and stay consistent. Headwinds, mountains, roof racks, heavy loads, and aggressive driving all cut economy, so pad the estimate 5-10% for a worst-case budget.
The per-person split assumes everyone shares fuel equally — handy for carpools and group trips. It covers fuel only; tolls, parking, food, and lodging are separate. For an electric vehicle, substitute cost-per-charge math instead, or use the EV vs gas comparison tool to weigh the difference.
Worked example
600-mile trip at 30 mpg, $3.50/gal, split 2 ways
- Gallons needed = 600 miles ÷ 30 mpg = 20 gallons.
- Total fuel cost = 20 gallons × $3.50 = $70.00.
- Cost per person = $70.00 ÷ 2 = $35.00.
- Fuel cost per mile = $70.00 ÷ 600 = $0.117.
Total fuel cost $70.00 | Gallons needed 20.00 | Cost per person $35.00 | Fuel cost per mile $0.117
Fuel cost for a 1,000-mile trip by MPG and gas price
| Fuel economy | $3.00/gal | $3.50/gal | $4.00/gal | $4.50/gal |
|---|---|---|---|---|
| 20 mpg | $150.00 | $175.00 | $200.00 | $225.00 |
| 25 mpg | $120.00 | $140.00 | $160.00 | $180.00 |
| 30 mpg | $100.00 | $116.67 | $133.33 | $150.00 |
| 40 mpg | $75.00 | $87.50 | $100.00 | $112.50 |
Key terms
- MPG (miles per gallon)
- How many miles a vehicle travels on one gallon of fuel; higher is more efficient.
- Fuel cost per mile
- Total fuel cost divided by miles driven — a simple measure of trip efficiency.
- Highway vs city MPG
- EPA rates fuel economy separately for city and highway driving; road trips track closer to the highway figure.
- Round-trip distance
- The total there-and-back mileage; double a one-way distance if you'll return the same way.
Frequently asked questions
- How do I calculate gas cost for a trip?
- Divide the trip distance by your car's MPG to get gallons needed, then multiply by the price per gallon. For a 600-mile trip at 30 mpg and $3.50/gal, that's 20 gallons × $3.50 = $70.
- Should I use city or highway MPG?
- Use highway MPG for road trips, since most miles are at steady highway speeds. City MPG would overstate fuel use. Your real-world average may differ from the EPA rating.
- Does this include the return trip?
- Only if you enter the round-trip distance. If you enter a one-way distance and plan to return, double it before calculating.