Travel
Work out fuel economy from distance driven and fuel used — litres per 100 km, kilometres per litre, and miles per gallon.
Results update as you type. No calculate button. All calculations run locally in your browser.
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| Measure | Value |
|---|
US MPG uses US gallons (3.785411784 L); UK MPG uses imperial gallons (4.54609 L) — the UK figure is always higher for the same car.
Bars are scaled to the 600 km trip. Fuel for a trip = rate (L/100km) × trip distance ÷ 100.
L/100 km = litres ÷ kilometres × 100. US MPG converts kilometres and litres to miles and US gallons: MPG (US) = (km ÷ 1.609344) ÷ (L ÷ 3.785411784). UK MPG uses 4.54609 L per gallon instead. Km/L = kilometres ÷ litres.
| Constant | Value |
|---|---|
| 1 mile | 1.609344 km |
| 1 US gallon | 3.785411784 L |
| 1 UK (imperial) gallon | 4.54609 L |
600 km on 45 L: 45 ÷ 600 × 100 = 7.5 L/100km; 600 ÷ 45 = 13.333333 km/L. Miles = 600 ÷ 1.609344 = 372.822715; US gallons = 45 ÷ 3.785411784 = 11.887742, so US MPG = 372.822715 ÷ 11.887742 = 31.361944. UK gallons = 45 ÷ 4.54609 = 9.898616, so UK MPG = 372.822715 ÷ 9.898616 = 37.664125.
A single tank-to-tank figure is noisy: fill level, route, weather, load, and driving style all move it. Use fuel added over a comparable full-tank interval, as the source tool advised, and average several tanks for a reliable figure. Manufacturer figures are measured on test cycles and usually beat real-world results. Display values are rounded to 6 decimal places.
Roughly: under 6 is economical, 6–9 is mid-range for a family petrol car, above 9 is thirsty. Diesels, hybrids, and electric cars are not directly comparable on this scale.
Same car, bigger gallon: an imperial gallon (4.54609 L) holds about 20% more fuel than a US gallon (3.785411784 L), so the same distance per litre reads higher in UK MPG.
US MPG = 235.214583 ÷ L/100km. For 7.5 L/100km that gives 31.361944, matching the worked example.
Several. One tank is easily skewed by how full the pump stops. Average over at least three comparable fill-ups.
No — this page measures consumption only. The fuel-cost calculator (linked below) turns consumption into money.
Results are estimates only and do not constitute professional advice.