Page published October 27, 2026
Get the free Car Buyer’s Cheat Sheet, 7 things to know before you sign anything. The numbers that matter, in plain English, on one page.
Join the Driveonomics email list. Occasional useful updates, no spam, unsubscribe anytime.
Gas is only the fuel line. Tolls, food, lodging, and wear on the car sit outside it, and highway prices on the route will differ from the national average.
The trip math
Miles divided by miles per gallon gives gallons. Gallons times the gas price gives the gas cost. For the main example: 1,200 miles divided by 25 miles per gallon equals 48 gallons. 48 gallons times $4.29 equals $205.92. That is the whole formula, and it is worth running with your own car mileage and the prices on your route, since both move the answer more than any other input.
Formula
The formula is two steps. Miles divided by miles per gallon gives gallons, and gallons times the gas price gives the gas cost. For the main example, a 1,200 mile round trip in a 25 mile per gallon family SUV: 1,200 divided by 25 equals 48 gallons, and 48 gallons times $4.29 equals $205.92. The table on this page runs the same two steps at four more distances: a 500 mile trip, 20 gallons, $85.80; a 600 mile trip, 24 gallons, $102.96; a 2,000 mile trip, 80 gallons, $343.20; and the same 1,200 miles in a 30 mile per gallon sedan, 40 gallons, $171.60, which is $34.32 less than the SUV because 40 gallons replace 48.
Two inputs move the answer more than any other. First, mileage: the sedan line shows what mileage is worth on a trip, the same 1,200 miles cost $34.32 less in a 30 mile per gallon sedan than in a 25 mile per gallon SUV. Loaded roof boxes, heavy luggage, and fast highway speeds all cut real mileage below the rated figure, so treat the rated miles per gallon as a starting point and the trip total as a planning figure, not a promise. Second, the gas price: this page uses $4.29 a gallon, the AAA national regular average reported October 26, 2026, as the dated price for a page published October 27, 2026. Pump prices on any actual route will differ, so run the formula with your own car mileage and the prices on your route. Gas is only the fuel line: tolls, food, lodging, and wear on the car sit outside it.
| Trip | Vehicle | Gallons | Gas cost |
|---|---|---|---|
| 500 miles, one way weekend trip | 25 mpg SUV | 20.0 | $85.80 |
| 600 miles, short round trip | 25 mpg SUV | 24.0 | $102.96 |
| 1,200 miles, family round trip | 25 mpg SUV | 48.0 | $205.92 |
| 1,200 miles, family round trip | 30 mpg sedan | 40.0 | $171.60 |
| 2,000 miles, long round trip | 25 mpg SUV | 80.0 | $343.20 |
The sedan line shows what mileage is worth on a trip: the same 1,200 miles cost $34.32 less in a 30 mpg sedan than in a 25 mpg SUV, because 40 gallons replace 48. Loaded roof boxes, heavy luggage, and fast highway speeds all cut real mileage below the rated figure, so treat the rated miles per gallon as a starting point and the trip total as a planning figure, not a promise.
What gas does not cover on a trip
Wear on tires, oil, and brakes for the trip miles is real but small next to gas, and it is already inside the upkeep lines on the model cost pages rather than in this trip total. Tolls vary by route and can rival gas on some corridors, food and lodging dwarf gas on multi day trips, and a hotel night can cost more than the whole gas bill for a 1,200 mile trip. Budget gas with this formula, then budget the trip around it.
For what a car costs to run across a whole year, not just one trip, use the calculator or start from what it costs per mile to drive.
Figures: gas price $4.29 a gallon, the AAA national regular average reported October 26, 2026, used as the dated price for this page published October 27, 2026. Pump prices on any actual route will differ. Mileage figures of 25 and 30 miles per gallon are examples, not ratings for any specific vehicle.
Educational estimates only, not financial, tax, legal or insurance advice. Every figure on this page is a typical example worked from the inputs stated on the page, not a quote for a specific car, loan, or driver. Your rate, insurance, fuel use, and resale value will move your total. See Terms.
Calculation transparency
Scope. Gas cost only, for a family road trip, worked from one formula at four distances in a 25 mile per gallon family SUV, with one 30 mile per gallon sedan line for comparison. Tolls, food, lodging, and wear on the car sit outside the total.
Rules and time period. Gas $4.29 a gallon, the AAA national regular average reported October 26, 2026, used as the dated price for this page published October 27, 2026; mileage figures of 25 and 30 miles per gallon are examples, not ratings for any specific vehicle; trips of 500, 600, 1,200, and 2,000 miles.
Scope and limitations. Educational estimate only. This page prices gas only: tolls vary by route and can rival gas on some corridors, food and lodging dwarf gas on multi day trips, and a hotel night can cost more than the whole gas bill for a 1,200 mile trip. Wear on tires, oil, and brakes for the trip miles is real but small next to gas. Pump prices on any actual route will differ from the national average, so check route prices before leaving. Prices vary by car, shop, and city. Get a written quote for your own car before you decide.
Source links checked November 6, 2026. Figures: Gas price $4.29 a gallon, the AAA national regular average reported October 26, 2026, via the AAA fuel price averages. Mileage figures of 25 and 30 miles per gallon are examples, not ratings for any specific vehicle.
Primary sources: AAA fuel prices; What does it cost per mile to drive; Honda Odyssey true cost; Toyota Sienna true cost. How the numbers are calculated is written down on the methodology page, and every source is listed on the sources page.
Definitions
Gallons. Miles divided by miles per gallon. On this page, 1,200 miles divided by 25 miles per gallon equals 48 gallons.
Gas cost. Gallons times the gas price. On this page, 48 gallons times $4.29 equals $205.92 for the 1,200 mile trip.
Miles per gallon. How far a car goes on one gallon of gas. On this page, 25 miles per gallon for the family SUV and 30 for the sedan, as examples, not ratings for any specific vehicle.
Trip total. The gas cost for one trip at one distance. On this page, $85.80 for 500 miles, $102.96 for 600 miles, $205.92 for 1,200 miles, and $343.20 for 2,000 miles, all in the 25 mile per gallon SUV.
Planning figure. A number to budget with, not a promise. Treat the rated miles per gallon as a starting point and the trip total as a planning figure, because real mileage falls below the rated figure with roof boxes, luggage, and fast highway speeds.
Questions people actually ask
How much does gas cost for a 1,200 mile family road trip?
In a 25 mile per gallon family SUV at $4.29 a gallon, $205.92. The math is 1,200 miles divided by 25 miles per gallon, which is 48 gallons, times $4.29. In a 30 mile per gallon sedan the same trip costs $171.60, from 40 gallons times $4.29.
What is the formula for road trip gas cost?
Miles divided by miles per gallon, times the gas price. Miles divided by miles per gallon gives gallons, and gallons times the gas price gives the gas cost. Run it with your own car mileage and the prices on your route, since both move the answer more than any other input.
What gas price does this page use?
The AAA national regular average of $4.29 a gallon reported October 26, 2026, used as the dated price for this page published October 27, 2026. Pump prices on any actual route will differ from the national average, so check route prices before leaving.
Does the trip total include tolls, food, and hotels?
No. This page prices gas only. Tolls vary by route and can rival gas on some corridors, food and lodging dwarf gas on multi day trips, and wear on tires, oil, and brakes for the trip miles is real but small next to gas. Budget gas with this formula, then budget the trip around it.
How much does gas cost for a 600 mile road trip?
In a 25 mile per gallon family SUV at $4.29 a gallon, $102.96. The math is 600 miles divided by 25 miles per gallon, which is 24 gallons, times $4.29.
Related: the trip cars: Honda Odyssey, about $969 a month and Toyota Sienna, about $946 a month. plan the budget around the trip: can a family car fit $400 or $600 a month, family cars under $400 a month, minivan vs 3-row SUV cost, do you really need a 3-row SUV, mid-size vs full-size 3-row SUV cost.