Why is mpg-calculator an alias?

MPG calculation and fuel-efficiency costing share this page.

Can I enter kilometers and liters?

Not directly. Convert to statute miles and US gallons first.

Does cost per mile include insurance?

No. Only fuel price divided by MPG.

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Fuel Efficiency and Cost-per-Mile Calculator

Turn odometer and fill-up data into MPG, metric consumption, and fuel cost per mile.

Trip MPG

L/100km conversion

Fuel cost per mile

Divides miles by gallons for MPG, converts to L/100km, and divides fuel price by MPG for cost per mile.

Limitation: Uses US gallons and statute miles.

Jump to calculator · Sources & review

Free Calculators HubFuel Efficiency Calculator

CurrencyMiles drivenGallons used (US)Fuel price per gallon

How to Calculate Fuel Efficiency

Use one fill-up interval measured in US gallons and statute miles.

Reset or note the odometer at fill-up.

Keep units consistent

If your pump uses liters, convert to US gallons before entry. Imperial gallons are not supported.

What the Fuel Efficiency Result Means

MPG is observed trip efficiency only. Cost per mile uses the entered price and does not include maintenance, insurance, or depreciation.

Fuel Efficiency Examples

300-mile tank

Entered trip fuel data

milesDriven:300

gallonsUsed:10

fuelPricePerGallon:3.5

MPG and cost per mile

30 MPG; 7.84 L/100km; 0.1167 per mile

300 ÷ 10 = 30 MPG; price divided by MPG is cost per mile.

City loop

Entered trip fuel data

milesDriven:120

gallonsUsed:6

fuelPricePerGallon:4

MPG and cost per mile

20 MPG; 0.20 per mile

Lower MPG raises cost per mile at the same fuel price family.

Average several tanks

One short tank can mislead. Average multiple fill-ups before comparing vehicles.

Frequently Asked Questions

No. It measures your entered trip. EPA labels use standardized test cycles.

Still have questions about this calculation?

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Fuel Efficiency Formulas

Conversions use the NIST US gallon and statute mile relationships.

Formula

miles driven ÷ gallons used

Miles per gallon

miles driven ÷ gallons used

Liters per 100 km

(100 × 3.785411784) ÷ (MPG × 1.609344)

Cost per mile

fuel price per gallon ÷ MPG

Scientific Background

Assumptions: US gallons, statute miles, and one homogeneous fuel price. Limitations: temperature, load, speed, tire pressure, and blend quality change real MPG; EPA window-sticker values are laboratory estimates, not this trip worksheet.

Sources & review

Fuel Efficiency Calculator documents the references behind its formulas and assumptions. Always treat results as educational estimates, not personalized professional advice.

Last reviewed

July 22, 2026

Reference
fueleconomy.gov
https://www.fueleconomy.gov/feg/pdfs/guides/FEG2017.pdf
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