Convert Miles per Imperial Gallon to US Gallons per 100 Miles
Convert Miles per Imperial Gallon (mpg (Imp)) to US Gallons per 100 Miles (US gal/100mi) instantly and accurately.
Conversion Formula
US gal/100mi = 120.0949926 ÷ mpg (Imp)
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).
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.
Quick Reference Table
| Miles per Imperial Gallon (mpg (Imp)) | US Gallons per 100 Miles (US gal/100mi) |
|---|---|
| 1 mpg (Imp) | 120.095 US gal/100mi |
| 2 mpg (Imp) | 60.0475 US gal/100mi |
| 5 mpg (Imp) | 24.019 US gal/100mi |
| 10 mpg (Imp) | 12.0095 US gal/100mi |
| 25 mpg (Imp) | 4.8038 US gal/100mi |
| 50 mpg (Imp) | 2.4019 US gal/100mi |
| 100 mpg (Imp) | 1.20095 US gal/100mi |