Based on data from 71 vehicles, 4,438 fuel-ups and 1,430,009 miles of driving, the 2021 GMC Sierra 2500 HD gets a combined Avg MPG of 13.18 with a 0.11 MPG margin of error.

Any Engine Type 6.6L V8 DIESEL (53) 6.6L V8 GAS (17) Any Body Style Extended Cab Pickup (1) Crew Cab Pickup (17) Any Submodel Base (2) SLE (7) SLT (10) AT4 (23) Denali (29)

Below you can see a distribution of the fuel-ups with 19 outliers (0.43%) removed.

Following shows the average MPG of each of the 71 vehicles in the system.

• «
• 2
• 3
• 4
• »

• GMC

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed Crew Cab Pickup
  Added Jul 2024 • 8 Fuel-ups

  Property of JK27

• 12.9 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

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed Crew Cab Pickup
  Added Jul 2021 • 71 Fuel-ups

  Property of mkirbitz

• 16.3 Avg MPG

• 2021 GMC Sierra Denali

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Feb 2024 • 4 Fuel-ups

  Property of chuckbench

• 13.2 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD AT4 6.6L V8 DIESEL Automatic 10 Speed
  Added Feb 2024 • 8 Fuel-ups

  Property of mstewart747

• 16.5 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD AT4 6.6L V8 DIESEL Automatic 10 Speed Crew Cab Pickup
  Added Aug 2023 • 12 Fuel-ups

  Property of bgeisick

• 16.7 Avg MPG

• 2021 2500HD Denali

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed Crew Cab Pickup
  Added Apr 2021 • 115 Fuel-ups

  Property of DP68

• 17.2 Avg MPG

• 2021 Sierra Denali HD

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Feb 2021 • 118 Fuel-ups

  Property of ccc2511

• 16.1 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Dec 2020 • 90 Fuel-ups

  Property of russellruetz

• 13.7 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD AT4 6.6L V8 DIESEL Automatic 10 Speed
  Added Oct 2022 • 18 Fuel-ups

  Property of 656mike

• 12.8 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD SLT 6.6L V8 GAS Automatic 6 Speed
  Added Jul 2021 • 88 Fuel-ups

  Property of scottshon

• 11.9 Avg MPG

• Black GMC Truck

  2021 GMC Sierra 2500 HD SLE 6.6L V8 GAS Automatic 6 Speed Extended Cab Pickup
  Added May 2021 • 32 Fuel-ups

  Property of Zeak1

• 14.1 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Apr 2021 • 14 Fuel-ups

  Property of jtrenaryf350

• 16.0 Avg MPG

• SIERRA 2500 HD

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Nov 2020 • 27 Fuel-ups

  Property of c00permj

• 14.3 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD AT4 6.6L V8 DIESEL Automatic 10 Speed
  Added Mar 2021 • 87 Fuel-ups

  Property of penaf71

• 11.1 Avg MPG

• AT4

  2021 GMC Sierra 2500 HD AT4 6.6L V8 DIESEL Automatic 10 Speed Crew Cab Pickup
  Added Jul 2022 • 5 Fuel-ups

  Property of Bluerock1

• 11.1 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD SLT 6.6L V8 GAS Automatic 6 Speed
  Added Mar 2021 • 14 Fuel-ups

  Property of Gordy86

• 14.3 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD AT4 6.6L V8 DIESEL Automatic 10 Speed
  Added Mar 2022 • 4 Fuel-ups

  Property of tgutwein

• 15.7 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Sep 2021 • 32 Fuel-ups

  Property of anon1234

• 15.5 Avg MPG

• 2021 AT4

  2021 GMC Sierra 2500 HD AT4 6.6L V8 DIESEL Automatic 10 Speed Crew Cab Pickup
  Added Jan 2021 • 51 Fuel-ups

  Property of TGriffi1

• 16.1 Avg MPG

• «
• 2
• 3
• 4
• »