2023 Subaru Outback MPG. Based on data from 119 vehicles, 2,757 fuel-ups and 880,235 miles of driving, the 2023 Subaru Outback gets a combined Avg MPG of 24.51 with a 0.20 MPG margin of error. Below you can see a distribution of the fuel-ups with 33 outliers (1.18%) removed.