U.S. National Average
$4.27/gal
EIA week of
October 26, 2026
U.S. National Average
$4.27/gal
EIA week of October 26, 2026
Road Trip Calculator
Enter the one way distance, your MPG and the gas price. The calculator returns the one way and round trip fuel cost and the gallons the round trip needs. Add an optional extra budget for lodging, food or tolls and it also shows a total trip budget.
How to Use This Calculator
Enter the one way distance
The calculator doubles it for the round trip. For a 1,200 mile round trip, enter 600; entering 1,200 would double count the miles and the fuel cost.
Enter the extra budget for the whole trip
It is added once to the round trip fuel cost, so add up lodging, food, parking and tolls in both directions rather than entering a daily amount.
Use the price where you will fill up
The price field starts at an average price. If most of your fuel will be bought somewhere pricier, use that price: each 10 cents per gallon adds $4.00 to a trip that needs 40 gallons.
Formula and Logic
The distance you enter is treated as one way, and every step is linear: double the distance or the price and the fuel cost doubles.
Step 1
One way miles ÷ MPG = gallons each wayStep 2
Gallons each way × gas price = one way fuel costStep 3
One way fuel cost × 2 = round trip fuel costStep 4
Round trip fuel cost + extra budget = total trip budgetMPG works the other way: fuel cost is proportional to 1 ÷ MPG, so dropping from 30 to 25 MPG raises the fuel cost by 20%, and dropping from 30 to 20 MPG raises it by 50%.
Example Calculations
Example 1: Weekend drive
Inputs
Result
300 ÷ 30 = 10 gallons each way, or $40.00 at $4.00. The $50 extra budget is added to the $80.00 round trip fuel cost.
Example 2: Family road trip
Inputs
Result
800 ÷ 25 = 32 gallons each way. Fuel is $268.80 of the $488.80 total, about 55%.
Example 3: 1,200 mile round trip vacation
Inputs
Result
Enter 600, half of the 1,200 mile round trip. Entering 1,200 would show $292.50 of fuel instead of $146.25.
Sample Road Trip Budget
Example: 500 miles each way, 30 MPG, $3.45 a gallon and 2 nights of lodging. Enter 500 as the distance and $350 (lodging, food and miscellaneous) as the extra budget, and the calculator shows the same $465.00 total.
Route by Route Cost Guides
The calculator handles any route you give it. For common drives, these guides work the numbers out in full, including the tolls and regional price differences a distance based estimate misses.