Budgeting & Income
Trip Fuel Cost Calculator
Planning a road trip or a commute budget? Enter the distance, your vehicle's fuel economy, and the price of gas to see how many gallons you'll burn and what the fuel will cost — one way or round trip.
Formula shown below · Tested against worked examplesHow we verify
Miles for a single leg of the trip.
Fuel cost: $70
Fuel cost
$70
Estimated gas for the trip.
- Gallons used
- 20
- Total miles
- 600
- Cost per mile
- $0.12
Fuel only — excludes wear, tolls, and parking.
Compare scenariosTry three values of one input
| Distance (one way) | |||
|---|---|---|---|
| Fuel cost | $63 | $70+$7 | $77+$14 |
| Gallons used | 18 | 20+2 | 22+4 |
| Total miles | 540 | 600+60 | 660+120 |
Every other input stays at the value you set above — currently 300 for distance (one way). Differences are measured against the first column.
Saved scenariosSave this calculation
Saved in this browser only — no account, and nothing is sent to us. Clearing your browser data deletes them.
How this calculator works
Total distance = one-way distance × 2 for a round trip. Gallons = total distance ÷ MPG. Fuel cost = gallons × price per gallon. Cost per mile divides the fuel cost by total miles.
Fuel only — it doesn't include depreciation, maintenance, insurance, tolls, or parking. For the all-in cost of driving (e.g. for reimbursement), use the IRS standard mileage rate instead.
Formula
Fuel used = Distance ÷ Efficiency
Cost = Fuel used × Price per unit- Distance
- Round trip, not one way
- Efficiency
- Miles per gallon, or the equivalent
- Price per unit
- Price per gallon
Fuel only. Tolls, parking and vehicle wear are real costs of driving and are excluded. Manufacturer efficiency figures are optimistic against real driving.
What this assumes
- Fuel cost from the distance, efficiency and price you enter. Real consumption varies with speed, load and terrain.
- Tolls, parking and vehicle wear are excluded unless entered, and wear is a real cost of driving.
- It costs fuel, not the trip — accommodation and food are separate.
What changes this number
- Fuel efficiency
- Varies substantially with driving style and load; the manufacturer figure is optimistic.
- Fuel price
- Moves the total directly and is the input most likely to have changed since you last checked.
- Distance
- Round trip, not one way. The most common error in this calculation.
A worked example
Take the 300 mi round trip, 30 mpg scenario. These figures are produced by the calculator above, not written alongside it, so they always match what the tool returns.
What you enter
- Distance (one way)
- 300
- Fuel economy (MPG)
- 30
- Gas price per gallon
- $4
- Round trip?
- Round trip (there and back)
What it returns
- Fuel cost
- $70
- Gallons used
- 20
- Total miles
- 600
- Cost per mile
- $0.12
Sources
This calculator uses no external data — the result follows entirely from the formula above and the values you enter, so there is nothing to cite beyond the arithmetic.
Calculator last reviewed August 9, 2026. How we verify
Try an example
Frequently asked questions
How do I calculate the fuel cost of a trip?
Divide the total distance by your car's miles-per-gallon to get gallons used, then multiply by the price per gallon. A 600-mile round trip at 30 MPG uses 20 gallons; at $3.50/gallon that's $70. This calculator does it for one-way or round trips.
Does this include the full cost of driving?
No — it's fuel only. The true cost of driving also includes depreciation, maintenance, tires, insurance, tolls, and parking. The IRS standard mileage rate (which bundles all of these) is often two to three times the fuel-only cost, so use that for reimbursement or true trip budgeting.
How can I lower my fuel cost?
Drive at steady speeds (fuel economy drops sharply above ~60 mph), keep tires properly inflated, remove excess weight and roof racks, combine errands, and keep up with maintenance. For frequent long trips, a more fuel-efficient or hybrid vehicle can pay back the difference over time.
What MPG should I use?
Use your car's real-world combined figure, not the sticker number, which is often optimistic — check a trip-computer average or fuelly-style logs. Highway trips beat the combined rating; lots of city stop-and-go comes in below it. Adjust the MPG input to match the kind of driving the trip involves.
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Disclaimer: DayCents provides this calculator for educational purposes only. Results are estimates based on your inputs and the stated assumptions — they are not financial advice, a quote, or an offer of credit. Consult a qualified financial professional before making major money decisions.