2018 GMC Sierra 1500 MPG and Fuel Cost

The 2018 GMC Sierra 1500 is rated 17 to 20 mpg combined across 14 EPA-tested gas versions; the best is the 4.3L 6-cyl · RWD · 6-speed automatic.

EPA fuel economy

2018 GMC Sierra 1500 · 14 EPA-tested versions

Best EPA rating

20MPG combined

18 city 24 highway

$3,250 a year to fuel

Fuel economy score4/10

4.3L 6-cyl · RWD · 6-speed automatic

Best version costs $4,750 more in fuel over 5 years vs the average new vehicle (EPA)

Fuel cost: 15,000 miles a year at EPA's $4.32 a gallon (regular gas).

Data: US EPA, fueleconomy.govUpdated Sep 27, 2026

At EPA's price assumptions, fuel costs $3,250 to $4,700 a year. Ratings for the best versions are unchanged from 2017.

Every 2018 Sierra 1500 version

EPA's ratings for each version it tested. Fuel cost is EPA's estimate for 15,000 miles a year at its current prices.

Version	Combined	City / Hwy	Fuel / year
4.3L 6-cyl · RWD · 6-speed automatic Best EPA listing: Sierra C15 2WD · Flex-fuel (E85)	20 mpg	18 / 24	$3,250
5.3L 8-cyl mild hybrid · RWD · 8-speed automatic EPA listing: Sierra 15 Hybrid 2WD	20 mpg	18 / 24	$3,250
4.3L 6-cyl · 4WD · 6-speed automatic EPA listing: Sierra K15 4WD · Flex-fuel (E85)	19 mpg	17 / 22	$3,400
5.3L 8-cyl · RWD · 6-speed automatic EPA listing: Sierra C15 2WD	19 mpg	16 / 23	$3,400
5.3L 8-cyl · RWD · 6-speed automatic · Flex-fuel (E85) EPA listing: Sierra C15 2WD · Flex-fuel (E85)	19 mpg	16 / 23	$3,400
5.3L 8-cyl mild hybrid · 4WD · 8-speed automatic EPA listing: Sierra 15 Hybrid 4WD	18 mpg	16 / 21	$3,600
5.3L 8-cyl · 4WD · 6-speed automatic EPA listing: Sierra K15 4WD	18 mpg	16 / 22	$3,600
5.3L 8-cyl · 4WD · 6-speed automatic · Flex-fuel (E85) EPA listing: Sierra K15 4WD · Flex-fuel (E85)	18 mpg	16 / 22	$3,600
5.3L 8-cyl · RWD · 8-speed automatic EPA listing: Sierra C15 2WD	18 mpg	16 / 22	$3,600
5.3L 8-cyl · 4WD · 6-speed automatic · Cab Chassis EPA listing: Sierra K15 Cab Chassis 4WD	17 mpg	15 / 19	$3,800
5.3L 8-cyl · 4WD · 8-speed automatic EPA listing: Sierra K15 4WD	17 mpg	15 / 20	$3,800
5.3L 8-cyl · RWD · 6-speed automatic · Cab Chassis EPA listing: Sierra C15 Cab Chassis 2WD	17 mpg	15 / 20	$3,800
6.2L 8-cyl · 4WD · 8-speed automatic EPA listing: Sierra K15 4WD · Premium fuel	17 mpg	15 / 20	$4,700
6.2L 8-cyl · RWD · 8-speed automatic EPA listing: Sierra C15 2WD · Premium fuel	17 mpg	15 / 21	$4,700

Fuel cost at your prices

EPA's annual cost uses 15,000 miles a year, 55% city driving and its current prices: $4.32 a gallon for regular gas and $5.32 a gallon for premium gas. Change the numbers to match your driving.

Version	Per year	Per month	5 years
4.3L 6-cyl · RWD · 6-speed automatic	$3,240	$270	$16,200
5.3L 8-cyl mild hybrid · RWD · 8-speed automatic	$3,240	$270	$16,200
4.3L 6-cyl · 4WD · 6-speed automatic	$3,411	$284	$17,053
5.3L 8-cyl · RWD · 6-speed automatic	$3,411	$284	$17,053
5.3L 8-cyl · RWD · 6-speed automatic · Flex-fuel (E85)	$3,411	$284	$17,053
5.3L 8-cyl mild hybrid · 4WD · 8-speed automatic	$3,600	$300	$18,000
5.3L 8-cyl · 4WD · 6-speed automatic	$3,600	$300	$18,000
5.3L 8-cyl · 4WD · 6-speed automatic · Flex-fuel (E85)	$3,600	$300	$18,000
5.3L 8-cyl · RWD · 8-speed automatic	$3,600	$300	$18,000
5.3L 8-cyl · 4WD · 6-speed automatic · Cab Chassis	$3,812	$318	$19,059
5.3L 8-cyl · 4WD · 8-speed automatic	$3,812	$318	$19,059
5.3L 8-cyl · RWD · 6-speed automatic · Cab Chassis	$3,812	$318	$19,059
6.2L 8-cyl · 4WD · 8-speed automatic	$4,694	$391	$23,471
6.2L 8-cyl · RWD · 8-speed automatic	$4,694	$391	$23,471

At the default settings the results match EPA's annual cost before EPA rounds it to the nearest $50.

GMC Sierra 1500 MPG by model year

The best-rated version in each model year; the highlighted year is this page. Gas: 19 to 21 mpg (every year from 2016 to 2026); highest in 2019. Diesel: 25 to 26 mpg (2020 to 2026); highest in 2020.

Best gas version
Best diesel version

2018: gas 20 mpg · diesel not offered

Show as a table

GMC Sierra 1500 best combined mpg by model year
Model year	Best gas version	Best diesel version
2016	20	–
2017	20	–
2018	20	–
2019	21	–
2020	21	26
2021	21	26
2022	20	26
2023	20	26
2024	20	25
2025	19	26
2026	20	25

How the 2018 Sierra 1500 compares

2018 full-size pickups covered on this site, ranked by their best combined rating. Fuel cost is for each model's cheapest version to run, at EPA's prices.

2018 model	Best combined	Best gas	Fuel / year
Ford F-150 Best: diesel	25 mpg	22 mpg	$2,950
Ram 1500 Best: diesel	23 mpg	20 mpg	$3,250
Chevrolet Silverado 1500 Best: gas	20 mpg	20 mpg	$3,250
GMC Sierra 1500 This page Best: gas	20 mpg	20 mpg	$3,250
Toyota Tundra Best: gas	16 mpg	16 mpg	$4,050

2018 Sierra 1500 recalls and complaints

NHTSA lists 7 safety recalls and 304 owner complaints for the 2018 Sierra 1500.What they cover, and crash test ratings

Questions

Does 4WD lower the 2018 GMC Sierra 1500's gas mileage?

Yes. On versions that differ only in drive, 4WD lowers the combined rating by 2 mpg: the 5.3L 8-cyl mild hybrid gets 20 mpg combined with two-wheel drive and 18 with 4WD.

Does the 2018 GMC Sierra 1500 need premium gas?

Some versions do. EPA lists the 6.2L 8-cyl versions on premium, the rest use regular.

How does the 2018 Sierra 1500's MPG compare with the 2017?

For 2018, the best gas version is rated 20 mpg, the same as the year before.

Sources and method

US EPA and Department of Energy fuel economy data (fueleconomy.gov), file dated Sep 18, 2026.
EPA fuel price assumptions: regular $4.32, midgrade $4.93, premium $5.32, diesel $6.29 a gallon; electricity $0.15 per kWh.
Recall and complaint counts: NHTSA recall file dated Sep 27, 2026 and complaint file dated Sep 26, 2026.

Ratings are EPA estimates. Real-world mileage depends on how, where and in what weather you drive. How we build these pages. Spotted an error? Tell us.