Against 247 other V6 cars rated 2024–2026, the Sierra sits right on their 21 mpg average. Averaged over the years each was sold, the most economical engine since 1989, the 3L 6-cyl (2020–2026), does 25.7 mpg and the thirstiest, the 5L 8-cyl (1997–1998), 15.5: $983 a year apart.
Every GMC Sierra engine, compared
Yearly cost assumes 12,000 miles at $3.20 a gallon.
| Engine | Combined | City / Highway | Years | Fuel per year |
|---|---|---|---|---|
| 3L 6-cyl | 23.1 / 29.3 | 2020–2026 | $1,494 | |
| 6L 8-cyl Hybrid | 20.4 / 22.6 | 2009–2013 | $1,811 | |
| 2.7L 4-cyl | 19 / 22.1 | 2019–2026 | $1,892 | |
| 6.2L 8-cyl | 16.8 / 22.4 | 1989–1993 | $2,021 | |
| 5.3L 8-cyl Hybrid | 16.9 / 21.1 | 2004–2018 | $2,098 | |
| 5.3L 8-cyl | 15.8 / 21.9 | 2007–2026 | $2,098 | |
| 6.5L 8-cyl | 16.3 / 21 | 1994–1996 | $2,133 | |
| 4.3L 6-cyl | 15.5 / 20.7 | 1989–2019 | $2,182 | |
| 4.8L 8-cyl | 14.4 / 19 | 1999–2006 | $2,356 | |
| 5L 8-cyl | 14 / 18.5 | 1997–1998 | $2,477 |
What that actually costs
Against its rivals in the same model years, the Ford F-150 gets 21.2 mpg, the RAM 1500 18.5 mpg and the Chevrolet Silverado 21 mpg, next to 21 mpg for the 2026 Sierra.
| Measure | Value |
|---|---|
| Cost per mile (2026) | $0.152 |
| Fuel per year | $1,829 |
| Fuel over five years | $9,145 |
| Against other V6 cars, 2024–2026 | about the same |
| EPA's own estimate | $3,488 a year |
City or highway — who is this car for
The 2026 GMC Sierra gives up 4.3 mpg in town: 23.3 on the highway against 19 in the city, $373 a year if every mile were city driving.
| Measure | Value | Reading |
|---|---|---|
| City (2026) | 19 mpg | $2,021 a year if you only drive in town |
| Highway | 23.3 mpg | $1,648 a year if you mostly commute |
| Gap | +4.3 mpg (23%) | Typical for its type |
How the Sierra changed over the years
The Sierra peaked in 2020 at 22.3 mpg (20 city, 25.7 highway) and was at its thirstiest in 2003 at 16 — 6.3 mpg apart, or $678 a year in fuel between buying one year and the other. The 2026 car does 21. The biggest single-year change came in 2020: 19 to 22.3 mpg.
| Model year | Combined | City / Highway | Engines offered | Fuel per year |
|---|---|---|---|---|
| 2026 | 19 / 23.3 | 3 | $1,829 | |
| 2025 | 19 / 23.7 | 3 | $1,829 | |
| 2024 | 19 / 23.7 | 3 | $1,829 | |
| 2023 | 19.7 / 23.7 | 3 | $1,803 | |
| 2022 | 19.3 / 24.3 | 3 | $1,803 | |
| 2021 | 20 / 25.3 | 3 | $1,745 | |
| 2020 | 20 / 25.7 | 3 | $1,722 | |
| 2019 | 17.7 / 22.3 | 3 | $2,021 | |
| 2018 | 17.3 / 23.7 | 3 | $1,949 | |
| 2017 | 17.3 / 23.7 | 3 | $1,949 | |
| 2016 | 17.3 / 23.3 | 3 | $1,949 | |
| 2015 | 17 / 23.5 | 2 | $1,969 | |
| 2014 | 17 / 23 | 2 | $1,969 | |
| 2013 | 16.7 / 21.7 | 3 | $2,053 | |
| 2012 | 16.7 / 21.7 | 3 | $2,053 | |
| 2011 | 16.7 / 21.7 | 3 | $2,053 | |
| 2010 | 17 / 21.3 | 3 | $2,021 | |
| 2009 | 17 / 21 | 3 | $2,098 | |
| 2008 | 15 / 20 | 2 | $2,259 | |
| 2007 | 15.3 / 19.3 | 3 | $2,259 | |
| 2006 | 15.3 / 19.3 | 3 | $2,259 | |
| 2005 | 15 / 19.3 | 3 | $2,299 | |
| 2004 | 15 / 19 | 3 | $2,356 | |
| 2003 | 14 / 19 | 2 | $2,400 | |
| 2002 | 14 / 18.5 | 2 | $2,400 | |
| 2001 | 14.5 / 19.5 | 2 | $2,327 | |
| 2000 | 14.5 / 20 | 2 | $2,259 | |
| 1999 | 14.5 / 20 | 2 | $2,327 | |
| 1998 | 15 / 19.5 | 2 | $2,327 | |
| 1997 | 14.5 / 20 | 2 | $2,259 |
MPG is a number. Dollars per year is the answer.
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How we count
This page rests on 96 EPA ratings of the GMC Sierra — 10 engines across 1989–2026. The mileage is EPA's laboratory figure, unchanged; the yearly bill is ours, at 12,000 miles and $3.20 a gallon, against EPA's own estimate of $3,488. Full method.
Frequently asked questions
What mpg does the 2026 GMC Sierra get?
21 mpg combined, 19 city and 23.3 highway, per EPA; its 3 versions that year range from 18 to 25. Across every year since 1989 the Sierra has averaged 18.7 mpg.
Is the 2026 Sierra more efficient than the 2025?
About the same: 21 against 21 mpg combined.
Which Sierra year has the best gas mileage?
The 2020, at 22.3 mpg combined (20 city, 25.7 highway).
Does the Sierra get better gas mileage than the Ford F-150?
About the same: 21 mpg for the 2026 Sierra against 21.2 for the 2026 Ford F-150.
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