How Required MPG Calculator Works?
This tool works by multiplying trip distance by the expected fuel price, then dividing by your maximum budget. The result is the lowest miles per gallon (MPG) a vehicle needs to finish the trip on budget.
Enter the trip distance
Type the full trip miles. The default is 420 miles (676 km).
Enter the maximum budget
Type the most you want to spend on fuel, for example $55.
Enter the expected fuel price
Type the price per gallon you expect along the route.
Read the required MPG
The tool shows the minimum MPG. Any vehicle at or above that figure fits the budget.
Required MPG Calculator Formula
The formula is Required MPG = (Distance × Fuel Price) ÷ Budget.
Required MPG = (Distance × Fuel Price) ÷ BudgetFormula variables
- Distance × Fuel Price
- Dollar cost of the trip at 1 MPG.
- Budget
- Maximum dollars available for fuel.
Worked example
- Trip Distance: 420 miles
- Maximum Budget: $55.00
- Expected Fuel Price: $3.65/gal
- Top line: 420 × $3.65 = $1,533.
- Required MPG: $1,533 ÷ $55 = 27.87 MPG (8.44 L/100km).
Result: 27.87 (MPG needed)
A compact SUV rated 30 MPG passes this test, while a pickup rated 20 MPG fails and costs $76.65 for the same trip.
Required MPG Calculator Conversion Table
The table shows required MPG for 4 trip distances at 4 budget levels, with fuel at $3.65 per gallon.
Rows: Trip Distance (miles). Columns: Maximum Budget ($). Cells: MPG needed.
| miles | $40.00 | $55.00 | $75.00 | $100.00 |
|---|---|---|---|---|
| 200 miles | 18.25 | 13.27 | 9.73 | 7.30 |
| 300 miles | 27.38 | 19.91 | 14.60 | 10.95 |
| 420 miles | 38.33 | 27.87 | 20.44 | 15.33 |
| 600 miles | 54.75 | 39.82 | 29.20 | 21.90 |
Values held constant: Expected Fuel Price = $3.65/gal.
A 600-mile (966 km) trip on a $40 budget needs 54.75 MPG, a target only hybrids and plug-in hybrids reach.
What is Required MPG Calculator?
The Required MPG Calculator is a tool that finds the minimum fuel economy needed to keep a trip within budget. The tool helps choose between vehicles before a trip.
Households with 2 or more cars, and travelers choosing a rental, pick the vehicle that clears the required MPG.
The tool works in reverse from most MPG tools. Instead of asking what a car costs to drive, the tool asks how efficient a car must be.
What are the uses of Required MPG Calculator?
There are 4 main uses of the Required MPG Calculator: choosing a rental car class, picking the family car for a trip, setting fleet vehicle standards, and screening used car listings.
Choosing a rental car class
Travelers compare economy and SUV rentals against a required MPG.
Picking the family car for a trip
Families choose between a sedan and a minivan for a long drive.
Setting fleet vehicle standards
Fleet buyers set a minimum MPG for new vehicles on fixed budgets.
Screening used car listings
Shoppers filter out cars below the MPG their monthly budget needs.
Need every metric in one place? Open the main MPG Cost Calculator or browse all 101 fuel calculators.