How Different Outbound and Return MPG Calculator Works?
This tool works by pricing each leg of a round trip with its own miles per gallon (MPG), then adding the 2 costs. Fuel is priced at $3.60 per gallon.
Enter outbound MPG
Type the MPG for the trip out. Uphill climbs, headwinds, and a full load lower this number.
Enter return MPG
Type the MPG for the trip back. Downhill grades and lighter loads raise this number.
Enter the leg distance
Type the one-way distance, for example 150 miles (241 km).
Read the total cost
The tool calculates gallons for each leg, adds them, and prices the total.
Different Outbound and Return MPG Calculator Formula
The formula is Total Cost = ((Distance ÷ Outbound MPG) + (Distance ÷ Return MPG)) × $3.60.
Total Cost = ((Distance ÷ Outbound MPG) + (Distance ÷ Return MPG)) × $3.60Formula variables
- Distance ÷ Outbound MPG
- Gallons burned on the trip out.
- Distance ÷ Return MPG
- Gallons burned on the trip back.
- $3.60
- Fixed fuel price per US gallon (3.785 L).
Worked example
- Outbound MPG (e.g. uphill/wind): 24 MPG
- Return MPG (e.g. downhill): 32 MPG
- Leg Distance: 150 miles
- Outbound gallons: 150 ÷ 24 = 6.25 gallons (23.7 L).
- Return gallons: 150 ÷ 32 = 4.69 gallons (17.7 L).
- Total: (6.25 + 4.69) × $3.60 = 10.94 × $3.60 = $39.38.
Result: $39.38
Averaging the 2 MPG values gives the wrong answer. The average of 24 and 32 is 28 MPG, which prices the trip at $38.57, $0.80 below the true cost of $39.38.
Different Outbound and Return MPG Calculator Conversion Table
The table shows round-trip cost for 5 outbound MPG values and 3 return MPG values on a 150-mile leg.
Rows: Outbound MPG (e.g. uphill/wind) (MPG). Columns: Return MPG (e.g. downhill) (MPG). Cells: $.
| MPG | 24 MPG | 32 MPG | 40 MPG |
|---|---|---|---|
| 16 MPG | $56.25 | $50.63 | $47.25 |
| 20 MPG | $49.50 | $43.88 | $40.50 |
| 24 MPG | $45.00 | $39.38 | $36.00 |
| 28 MPG | $41.79 | $36.16 | $32.79 |
| 32 MPG | $39.38 | $33.75 | $30.38 |
Values held constant: Leg Distance = 150 miles.
A slow 16 MPG climb with a 40 MPG descent costs $47.25, while an even 32 MPG in both directions costs $33.75.
What is Different Outbound and Return MPG Calculator?
The Different Outbound and Return MPG Calculator is a tool that prices a round trip where fuel economy differs between the 2 directions. The tool gives an accurate cost for mountain, desert, and towing routes.
Fuel economy changes with elevation, wind, and load. A drive from sea level to a ski town at 9,000 feet (2,743 m) burns more fuel going up than coming down.
The calculator treats each leg on its own and sums the gallons. This method follows the math of fuel use, where gallons add up but MPG values do not average in a straight line.
What are the uses of Different Outbound and Return MPG Calculator?
There are 5 main uses of the Different Outbound and Return MPG Calculator: pricing mountain trips, costing towing trips, planning windy desert drives, budgeting delivery runs with loads, and checking ski trip costs.
Pricing mountain trips
Drivers set a low MPG for the climb and a high MPG for the descent.
Costing towing trips
Boat owners enter 12 MPG with the trailer loaded and 20 MPG with the trailer empty.
Planning windy desert drives
Travelers account for a headwind on one leg and a tailwind on the other.
Budgeting delivery runs with loads
Contractors price a full truck out and an empty truck back.
Checking ski trip costs
Families add roof box drag on the way up and lighter gear loads on the way down.
Need every metric in one place? Open the main MPG Cost Calculator or browse all 101 fuel calculators.