2020 GMC Sierra Fuel Economy

EPA ratings by trim

City and highway are EPA's adjusted label figures; combined is the 55/45 blend printed on the window sticker. For electric and plug-in trims the MPG columns are MPGe, and the kWh per 100 miles is the figure a charging cost actually turns on; EPA measures it at the wall, so charging losses are already in it. Unrounded combined figures, where EPA publishes them: Sierra 2WD 17; Sierra 2WD 19.2176; Sierra 2WD 20.0462; Sierra 2WD 25.9462; Sierra 2WD 16.9515; Sierra 2WD 16.307; Sierra 2WD 21.0999; Sierra 2WD 19.8308; Sierra 4WD 18.1521; Sierra 4WD 18.5543; Sierra 4WD 20.0462; Sierra 4WD 16.9303; Sierra 4WD 16.79; Sierra 4WD 23.8267; Sierra 4WD 20.039; Sierra 4WD 16.724; Sierra 4WD 16.1974; Sierra 4WD AT4 18.2856; Sierra 4WD AT4 18; Sierra 4WD AT4 17.2528; Sierra 4WD AT4 16; Sierra 4WD AT4 23.8267; Sierra Cab Chassis 2WD 17; Sierra Cab Chassis 2WD 15.2644; Sierra Cab Chassis 4WD 14.9623; Sierra Cab Chassis 4WD 15.

What the rating costs per mile

The rating divided by a price, times your miles. It starts at EIA's current U.S. averages and EPA's 15,000 miles so the right-hand column is comparable; type your own pump price, home rate and mileage over them.

Fuel only — before depreciation, insurance, maintenance or tires, which the True Cost per Mile Calculator adds. Most drivers land below the rating; the True MPG Calculator measures your own from two fill-ups.

EPA's own figures, and why they differ

The “EPA's figure” column is EPA's annual fuel cost from the same file: 15,000 miles, 55% city, and the national fuel price fueleconomy.gov was using on the day the file was built (2026-09-29). fueleconomy.gov recomputes its page every week at the current price, so its number and the file's drift apart between file dates; the middle columns here use a price you can see and change, which is the only honest way to compare two cars. EPA also prints a five-year “you save/spend” against the average new vehicle (spends $6,500 for the Sierra 2WD); it rests on the same assumptions and is not repeated here as a result.

Every figure on this page is a rating, not a measurement of any particular car. The site never calls a rating wrong; it shows what your own price and miles do to it. See the model on fueleconomy.gov.

Other model years of the GMC Sierra: 2026, 2025, 2024, 2023, 2022, 2021, 2019, 2018, 2017, 2016, 2015, 2014, 2013, 2012, 2011, 2010, 2009, 2008, 2007, 2006, 2005, 2004, 2003, 2002, 2001, 2000, 1999, 1998, 1997, 1996, 1995, 1994, 1993, 1992, 1991, 1990, 1989.