Based on data from 63 vehicles, 3,541 fuel-ups and 1,134,144 miles of driving, the 2021 GMC Sierra 2500 HD gets a combined Avg MPG of 13.15 with a 0.13 MPG margin of error.

Any Engine Type 6.6L V8 DIESEL (45) 6.6L V8 GAS (17) Any Body Style Extended Cab Pickup (1) Crew Cab Pickup (14) Any Submodel Base (2) SLE (6) SLT (7) AT4 (21) Denali (27)

Below you can see a distribution of the fuel-ups with 13 outliers (0.37%) removed.

Following shows the average MPG of each of the 63 vehicles in the system.

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• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD SLE 6.6L V8 DIESEL Automatic 6 Speed
  Added Apr 2023 • 158 Fuel-ups

  Property of mcgr0401

• 12.3 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD AT4 6.6L V8 DIESEL Automatic 10 Speed
  Added Sep 2023 • 130 Fuel-ups

  Property of SeB21

• 17.1 Avg MPG

• 2021

  2021 GMC Sierra 2500 HD Denali Crew Cab Pickup
  Added Dec 2020 • 167 Fuel-ups

  Property of lampmant

• 12.8 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD AT4 6.6L V8 GAS Automatic 6 Speed
  Added Jun 2021 • 159 Fuel-ups

  Property of gregnola

• 12.4 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD AT4 6.6L V8 GAS Automatic 6 Speed
  Added May 2021 • 195 Fuel-ups

  Property of Buellx72

• 11.5 Avg MPG

• DENALI 2021

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed Crew Cab Pickup
  Added Dec 2020 • 93 Fuel-ups

  Property of rivcoinc

• 14.4 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Dec 2020 • 95 Fuel-ups

  Property of mbrent77

• 16.0 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD Denali 6.6L V8 GAS Automatic 6 Speed
  Added Nov 2021 • 121 Fuel-ups

  Property of Danm1228

• 11.6 Avg MPG

• 21 Denali HD

  2021 GMC Sierra 2500 HD Denali 6.6L V8 GAS Automatic 6 Speed
  Added Apr 2021 • 37 Fuel-ups

  Property of shreff86

• 11.0 Avg MPG

• 2500Hd GMC

  2021 GMC Sierra 2500 HD AT4 6.6L V8 DIESEL Automatic 10 Speed Crew Cab Pickup
  Added May 2021 • 121 Fuel-ups

  Property of jmgolden1978

• 14.0 Avg MPG

• AT4 Whore

  2021 GMC Sierra 2500 HD AT4 6.6L V8 DIESEL Automatic 10 Speed
  Added Mar 2021 • 136 Fuel-ups

  Property of pigpen23

• 12.3 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Apr 2023 • 29 Fuel-ups

  Property of Jdcompman

• 15.9 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD SLT 6.6L V8 GAS Automatic 6 Speed
  Added Jan 2021 • 200 Fuel-ups

  Property of kbeazley

• 10.7 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD SLE 6.6L V8 GAS Automatic 10 Speed
  Added Oct 2021 • 129 Fuel-ups

  Property of bdamats

• 11.4 Avg MPG

• AT4

  2021 GMC Sierra 2500 HD AT4 6.6L V8 DIESEL Automatic 10 Speed Crew Cab Pickup
  Added Oct 2022 • 61 Fuel-ups

  Property of scrabble890

• 14.7 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD SLE 6.6L V8 DIESEL Automatic 10 Speed
  Added Mar 2024 • 8 Fuel-ups

  Property of fredc941

• 12.1 Avg MPG

• 2021 Sierra 2500HD

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed Crew Cab Pickup
  Added Jan 2024 • 19 Fuel-ups

  Property of Bost05

• 12.7 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD SLT 6.6L V8 GAS Automatic 6 Speed
  Added Jan 2021 • 32 Fuel-ups

  Property of NGreen08

• 10.5 Avg MPG

• 2021 Sierra Denali HD

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Dec 2020 • 163 Fuel-ups

  Property of LynnE24

• 14.4 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD SLE 6.6L V8 DIESEL Automatic 10 Speed
  Added Jan 2023 • 80 Fuel-ups

  Property of Croybal06

• 13.5 Avg MPG

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