How do MPG and L/100km relate?

To convert US MPG to L/100km: divide 235.21 by the MPG number. So 30 MPG is about 7.84 L/100km. UK MPG differs because the UK gallon is 20% larger - 30 UK MPG is about 9.41 L/100km.

Is higher MPG always better?

Yes - higher MPG means more miles per gallon, which is lower L/100km. The confusion is that L/100km: lower is better, while MPG: higher is better. This tool shows both so you do not mix them up.

How much fuel does a typical car use?

New compact cars: 5-7 L/100km (34-47 MPG). SUVs/trucks: 10-15 L/100km (16-24 MPG). Hybrid cars: 3-5 L/100km (47-78 MPG). Electric cars use kWh/100km instead.

⛽ Fuel Consumption Converter

Fuel economy speaks different languages on every continent. This converter handles MPG (US), MPG (UK), km per liter, and the European L/100km where LESS is BETTER — the inverse relationship trips up a lot of people.

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Last updated September 10, 2026 — all conversions use exact ISO 80000 unit definitions.

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How fuel consumption works

Fuel economy has two opposite conventions. MPG-style measures distance per fuel — higher is better. L/100km measures fuel per distance — lower is better. They are mathematical reciprocals, so doubling your MPG halves your L/100km figure. The US gallon is 3.785 L but the UK imperial gallon is 4.546 L — that's why UK MPG numbers are always higher than US MPG for the same car.

Real-world applications

Real-world: 50 UK MPG = 41.7 US MPG (UK gallon is 20% larger). Winter: -10-20% MPG for gas cars, -20-40% EV range below -10 C. Tesla Model 3 = 200 Wh/km = 3.2 L/100km equivalent.

Fuel economy reference

Vehicle type	US MPG	L/100km
Small gasoline car	35-40	5.9-6.7
Mid-size sedan	28-32	7.4-8.4
Full-size SUV	18-22	10.7-13.1
Hybrid compact	45-55	4.3-5.2
Diesel van	22-28	8.4-10.7
Electric (equivalent)	100+	~2.4 L equivalent

Frequently asked questions

Why does L/100km go down when MPG goes up?

They are inverse measures. MPG = distance divided by fuel. L/100km = fuel divided by distance. One is literally the reciprocal of the other (with unit conversions). Better fuel economy means higher MPG but lower L/100km.

US gallon vs UK gallon — what's the difference?

A US gallon is 3.785 liters. A UK imperial gallon is 4.546 liters — about 20% larger. That's why a UK-gallon MPG figure is higher than a US-gallon MPG for the same actual fuel economy.

What is a good fuel economy?

Below 6 L/100km (above 39 US MPG) is excellent. 6-8 L/100km is typical for modern sedans. Above 10 L/100km (below 24 MPG) is gas-guzzler territory. Electric vehicles use kWh/100km instead — roughly 6-8 kWh/100km is equivalent to about 29-39 L/100km gasoline.

Estimates are for general information only — see our disclaimer.

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