Petrol Expense Calculator
MPG fuel-cost tool

Fuel Cost per Mile

Enter real-world MPG and a petrol or gasoline price to calculate fuel cost per mile, cost per 100 miles, fuel used, and total expense for a journey.

Fuel cost per mile

0.117

Fuel cost per 100 miles

11.67

100 mile trip cost

11.67

Fuel used for trip

3.333 gal · 12.62 L

Results use the currency of your entered price. This is a fuel-only estimate; it excludes maintenance, tyres, insurance, tax, financing, and depreciation.

How to Use the Cost per Mile Calculator

  1. Enter your vehicle's measured miles per gallon.
  2. Select US MPG or Imperial MPG; do not treat them as interchangeable.
  3. Enter the fuel price and select price per gallon or price per litre.
  4. Optionally enter a trip distance in miles.
  5. Review cost per mile, cost per 100 miles, trip fuel, and total trip cost.

The calculator treats your currency as a label and performs no exchange-rate conversion. Use MPG measured in driving conditions similar to the planned journey.

Fuel Cost per Mile Formulas

Cost/mile = price per gallon ÷ MPG
Gallons per mile = 1 ÷ MPG
Cost/100 miles = cost/mile × 100
Trip cost = cost/mile × trip miles

When price is entered per litre, the tool calculates price per gallon first: price/litre × litres per selected gallon. It retains full numeric precision until displaying rounded results.

Worked Fuel-Cost-per-Mile Example

Inputs: 30 US MPG, USD 3.60 per US gallon, and a 250-mile trip.

Cost per mile = 3.60 ÷ 30 = USD 0.12

Cost per 100 miles = 0.12 × 100 = USD 12.00

Trip fuel = 250 ÷ 30 = 8.333 US gallons

Trip cost = 8.333 × 3.60 = USD 30.00

This example is illustrative. Replace MPG and price with values relevant to your vehicle, fuel, location, and driving conditions.

US MPG, Imperial MPG, Litres, and Gallons

US miles per gallon

US MPG measures miles travelled on one US gallon, equal to exactly 3.785411784 litres. If fuel costs 1.50 per litre, the equivalent US-gallon price is approximately 5.68 in the same currency.

Imperial miles per gallon

Imperial MPG uses an Imperial gallon of exactly 4.54609 litres. Because this gallon is larger, the same fuel efficiency has a higher numerical Imperial MPG value. To compare figures, 1 US MPG is approximately 1.20095 Imperial MPG.

Miles and kilometres

One mile equals exactly 1.609344 kilometres. This page focuses on mile-based costs and MPG. For metric planning, use the fuel cost per kilometre calculator.

What Changes Petrol Cost per Mile?

Fuel price

A petrol-price change immediately changes cost per mile even when MPG stays constant.

Route and traffic

Cold starts, short journeys, stop-start traffic, idling, gradients, rough roads, and wind can reduce real MPG.

Vehicle and load

Tyre pressure, engine condition, passengers, cargo, roof racks, trailers, and towing affect consumption.

Driving behaviour

High speed, harsh acceleration, heavy braking, and unnecessary idling can use more fuel for each mile.

For budgeting, calculate a measured average from several fill-ups rather than relying only on a dashboard's instant MPG reading. Recalculate when the fuel price or typical route changes.

Cost per Mile vs Total Running Cost

This tool calculates petrol or gasoline expense per mile. A full vehicle operating-cost or reimbursement rate may also include servicing, tyres, repairs, insurance, registration, tax, finance, depreciation, parking, and tolls. Do not present the fuel-only result as a complete ownership cost.

For a journey with one-way or return-trip options and passenger sharing, use the trip petrol calculator. For recurring budgets, use the monthly petrol calculator.

Limitations and Search-Intent Boundaries

The estimate assumes the entered MPG and price apply across the full distance. It does not fetch live prices or adjust automatically for traffic, temperature, terrain, wind, vehicle faults, load, towing, fuel quality, measurement error, or price changes between filling stations. Results are planning estimates, not invoices.

This page specifically answers mile-based fuel-cost questions using US or Imperial MPG. The separate cost-per-kilometre page serves metric intent, while the general petrol calculator supports broader distance and consumption units. Keeping these scopes distinct reduces duplicated content and keyword cannibalization.

FAQ

Fuel Cost per Mile FAQs

Answers about MPG types, gallon conversions, per-mile petrol cost, and trip estimates.

Methodology and Accuracy

The tool converts a litre price to the selected gallon when needed, divides by MPG to find fuel cost per mile, and multiplies by distance for a trip estimate. Exact conversion constants are 1 US gallon = 3.785411784 litres, 1 Imperial gallon = 4.54609 litres, and 1 mile = 1.609344 kilometres.

Read the petrol expense formula guide and shared calculation methodology. Last reviewed: 3 August 2026.

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