Trip Cost: worked example
| Trip distance (miles) | 900 |
|---|---|
| Fuel economy (mpg) | 28 |
| Fuel price per gallon | $3.40 |
| Tolls, parking and other costs | $45 |
| Travelers sharing the cost | 3 |
| Total trip cost | $154 |
| Cost per traveler | $51 |
| Gallons of fuel | 32.1 |
Trip Cost: formula
Trip distance is the total miles driven, including detours and the return journey, from a mapping app. Fuel economy is your vehicle's real-world miles per gallon, and fuel price is the average price you expect to pay along the route. Tolls, parking and other costs cover bridge fees, parking, and any car rental extras.
Travelers sharing the cost is the number of people splitting it.
Highway and city mileage differ, and loads, speed, weather and hills change fuel use. Fuel prices vary by state and can be higher on highways. The calculation does not include lodging, food or the wear on the vehicle.
The federal mileage rate used for business reimbursements is far higher than fuel cost alone because it includes wear and depreciation.
Common error: Leaving out wear. Fuel is the visible cost, but tires, oil and depreciation also grow with every mile, so the fuel-only figure understates the true cost of the drive.
Trip Cost: changing Fuel price per gallon
| Fuel price per gallon | Total trip cost | Cost per traveler | Gallons of fuel |
|---|---|---|---|
| $2.72 | $132 | $44 | 32.1 |
| $3.06 | $143 | $48 | 32.1 |
| $3.40 (example) | $154 | $51 | 32.1 |
| $3.74 | $165 | $55 | 32.1 |
| $4.08 | $176 | $59 | 32.1 |
Trip Cost: compare input ranges
| Input | Tested from | To | Total trip cost: low input | Total trip cost: high input | Swing |
|---|---|---|---|---|---|
| Fuel economy (mpg) | 25 | 31 | $167 | $144 | $24 (15%) |
| Trip distance (miles) | 810 | 990 | $143 | $165 | $22 (14%) |
| Fuel price per gallon | $3.06 | $3.74 | $143 | $165 | $22 (14%) |
| Tolls, parking and other costs | $41 | $50 | $150 | $159 | $9.00 (5.8%) |
| Travelers sharing the cost | 2 | 4 | $154 | $154 | $0.00 |
Trip Cost: individual input comparisons
| Input | Value | Total trip cost | Cost per traveler | Gallons of fuel |
|---|---|---|---|---|
| Trip distance (miles) | 720 | $132 | $44 | 25.7 |
| 810 | $143 | $48 | 28.9 | |
| 900 | $154 | $51 | 32.1 | |
| 990 | $165 | $55 | 35.4 | |
| 1,080 | $176 | $59 | 38.6 | |
| Fuel economy (mpg) | 22 | $184 | $61 | 40.9 |
| 25 | $167 | $56 | 36 | |
| 28 | $154 | $51 | 32.1 | |
| 31 | $144 | $48 | 29 | |
| 34 | $135 | $45 | 26.5 | |
| Fuel price per gallon | $2.72 | $132 | $44 | 32.1 |
| $3.06 | $143 | $48 | 32.1 | |
| $3.40 | $154 | $51 | 32.1 | |
| $3.74 | $165 | $55 | 32.1 | |
| $4.08 | $176 | $59 | 32.1 | |
| Tolls, parking and other costs | $36 | $145 | $48 | 32.1 |
| $41 | $150 | $50 | 32.1 | |
| $45 | $154 | $51 | 32.1 | |
| $50 | $159 | $53 | 32.1 | |
| $54 | $163 | $54 | 32.1 | |
| Travelers sharing the cost | 1 | $154 | $154 | 32.1 |
| 2 | $154 | $77 | 32.1 | |
| 3 | $154 | $51 | 32.1 | |
| 4 | $154 | $39 | 32.1 | |
| 5 | $154 | $31 | 32.1 |
Trip Cost: combined input changes
| Fuel price per gallon / Trip distance (miles) | 720 | 900 | 1,080 |
|---|---|---|---|
| $2.72 | $115 | $132 | $150 |
| $3.06 | $124 | $143 | $163 |
| $3.40 | $132 | $154 | $176 |
| $3.74 | $141 | $165 | $189 |
| $4.08 | $150 | $176 | $202 |
Trip Cost: which assumptions move the result?
Trip Cost: values and definitions
| Quantity and definition | Value used |
|---|---|
| Trip distance (miles) — The full distance driven, including the return trip. | 900 |
| Fuel economy (mpg) | 28 |
| Fuel price per gallon | $3.40 |
| Tolls, parking and other costs | $45 |
| Travelers sharing the cost | 3 |
| Total trip cost | $154 |
| Cost per traveler | $51 |
| Gallons of fuel | 32.1 |
Trip Cost: half and double Fuel economy (mpg)
| Fuel economy (mpg) | Total trip cost |
|---|---|
| 14 | $264 |
| 28 | $154 |
| 56 | $100 |
Auto Finance calculators: Auto Lease Calculator, Lease vs. Buy Calculator, Auto Depreciation Calculator, Fuel Cost Calculator, Vehicle Total Cost of Ownership Calculator, Lease Mileage Calculator.
For a separate explicitly assumed route, 1,000 miles at 30 mpg requires 33.333 gallons. At $3.40 a gallon, fuel costs about $113.33. Adding the same $45 of tolls and parking gives $158.33, or $52.78 each for three travelers.
That route is longer than the 900-mile example but uses better fuel economy, so distance alone does not determine its cost.
Use the mpg you get on the road. Highway numbers beat city numbers, and a loaded car, a roof box or a headwind can take 10 to 20 percent off.
See annual running costs with the fuel cost calculator, and compare energy costs with the EV vs gas calculator. The vehicle total cost of ownership page adds insurance and depreciation. The unit conversion calculators convert miles, kilometers and gallons.
How do I split trip costs fairly?
Divide fuel, tolls and parking by the number of travelers, and consider adding a share for wear on the car if the owner is driving.
Is driving cheaper than flying?
For groups and short distances often yes, since fuel costs are shared, while for one traveler over a long distance flying can cost less than the total cost of driving.
What is the real cost per mile of driving?
Fuel is only part. Depreciation, maintenance and insurance add to it, and the IRS business mileage rate reflects a fuller cost per mile.