Fuel Economy Calculator
Find your MPG, L/100km and km/L, plus total fuel cost and cost per mile.
MPGL/100kmkm/L
Fuel economy
Total fuel cost
$42.00
Cost per mile
$0.140
L/100km
9.41
km/L
10.63
MPG
25.0
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How fuel economy is calculated
- MPG = miles driven ÷ gallons used.
- L/100km = 235.215 ÷ MPG (lower is better).
- km/L = MPG × 0.42514.
- Total fuel cost = gallons used × price per gallon.
- Cost per mile = total fuel cost ÷ miles driven.
For the most accurate reading, measure miles and gallons between two full tank fill-ups. Smooth driving, correct tire pressure and less idling all improve economy.
Frequently Asked Questions
- How do I calculate MPG?
- Miles per gallon = miles driven ÷ gallons used. For example, 300 miles on 12 gallons is 25 MPG.
- How do I convert MPG to L/100km?
- L/100km = 235.215 ÷ MPG. So 25 MPG ≈ 9.41 L/100km. A lower L/100km number means better economy, the opposite of MPG.
- What is cost per mile?
- Cost per mile = total fuel cost ÷ miles driven, where total fuel cost = gallons used × price per gallon. It is a quick way to budget trips.
- How can I get an accurate reading?
- Fill the tank completely, reset your trip meter, then refill completely at the next stop. Use the miles and gallons between the two fill-ups for the most accurate result.
📅 Last updated: June 2026 · Formulas follow standard banking / tax conventions · Results are for reference only.