Convert US Gallons per 100 Miles to Miles per Imperial Gallon

Convert US Gallons per 100 Miles (US gal/100mi) to Miles per Imperial Gallon (mpg (Imp)) instantly and accurately.

US Gallons per 100 Miles (US gal/100mi)
Miles per Imperial Gallon (mpg (Imp))

Conversion Formula

mpg (Imp) = 120.0949926 ÷ US gal/100mi

About US Gallons per 100 Miles

US gallons per 100 miles is the volumetric consumption figure displayed alongside mpg on the EPA Monroney fuel-economy label on all new US vehicles since 2013. A smaller number means a more efficient car. At $4/gal, gal/100mi × 4 gives the dollar fuel cost per 100 miles. Ranges: 1.5-2 gal/100mi for efficient compacts (50-67 mpg); 2.5-3.5 for mainstream sedans (28-40 mpg); 4-6 for crossovers/light trucks (17-25 mpg). 1 US gal/100mi = 3.785411784/1.609344 = 2.3521 L/100km.

About Miles per Imperial Gallon

Miles per Imperial gallon (mpg(Imp)) is the UK and historically Commonwealth standard. The Imperial gallon (4.54609 L) is ~20.1% larger than the US gallon, so mpg(Imp) is always numerically higher: a 7 L/100km car achieves 33.6 mpg(US) but 40.4 mpg(Imp). All UK VCA-certified specs list mpg(Imp). Typical WLTP combined: supermini 45-60 mpg; full hybrid 55-75 mpg; diesel family car 48-68 mpg; large petrol SUV 28-38 mpg. 1 mpg(Imp) = 1.609344/4.54609 km/L = 0.354006 km/L; L/100km = 282.481/mpg(Imp).

Quick Reference Table

US Gallons per 100 Miles (US gal/100mi)Miles per Imperial Gallon (mpg (Imp))
1 US gal/100mi120.095 mpg (Imp)
2 US gal/100mi60.0475 mpg (Imp)
5 US gal/100mi24.019 mpg (Imp)
10 US gal/100mi12.0095 mpg (Imp)
25 US gal/100mi4.8038 mpg (Imp)
50 US gal/100mi2.4019 mpg (Imp)
100 US gal/100mi1.20095 mpg (Imp)

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