30-day trial. To keep it, please install GasLog Unlock Key for only US$0. 99. The ONLY app compares vehicle fuel economy with US EPA official ratings. Track vehicle gas mileage or fuel economy, i. E. MPG, L/100km, KM/L, or KPG. Comprehensive statistics, including MPG, mileage, fuel price, fuel cost, CO2 emission etc. Line charts and bar charts for MPG, fuel price, etc.