GMC
GMC Sierra 3500HD Bed Sizes & Dimensions
Inside bed length, width between the wheel wells and depth for the GMC Sierra 3500HD, 2015 to today — plus which camper shells and tonneau covers swap between years. The current truck comes with 6'9" or 8'2" beds.
2020–present Sierra 3500HD
Spot-check| Bed | Cabs | Length at floor | Max width | Between wheel wells | Depth | Volume |
|---|---|---|---|---|---|---|
| Standard Box 6'9" nominal |
Double Cab, Crew Cab | 82.2″ | 71.4″ | 50.8″ | 21″ | — |
| Long Box 8'2" nominal |
Regular Cab, Double Cab, Crew Cab | 98.3″ | 71.4″ | 50.8″ | 21″ | — |
Camper shell & cover swaps
Same bed box as:
A shell from one of these trucks with the same bed length should sit on the rails, but cab height, back-window angle, tailgate type and rail caps can still stop it from fitting. Confirm with the shell maker before you buy.
- The 2020+ HD bed is different from the 2019+ 1500 bed — HD and 1500 shells are not interchangeable in this generation.
- Dually (DRW) 3500s use the Long Box with wider outer fenders; inside dimensions are the same.
2015–2019 Sierra 3500HD
Spot-check| Bed | Cabs | Length at floor | Max width | Between wheel wells | Depth | Volume |
|---|---|---|---|---|---|---|
| Standard Box 6'6" nominal |
Double Cab, Crew Cab | 78.9″ | 62.3″ | 50.6″ | 22.4″ | — |
| Long Box 8'0" nominal |
Regular Cab, Double Cab, Crew Cab | 97.8″ | 62.3″ | 50.6″ | 22.4″ | — |
Camper shell & cover swaps
Same bed box as:
- Chevrolet Silverado 1500 2014–2018
- Chevrolet Silverado 2500HD 2015–2019
- Chevrolet Silverado 3500HD 2015–2019
- GMC Sierra 1500 2014–2018
- GMC Sierra 2500HD 2015–2019
A shell from one of these trucks with the same bed length should sit on the rails, but cab height, back-window angle, tailgate type and rail caps can still stop it from fitting. Confirm with the shell maker before you buy.
- Same bed box as the 2014–2018 Silverado/Sierra 1500.
Accessories that fit the GMC Sierra 3500HD
All accessories2020–now GMC Sierra 3500HD → all accessories
Bed covers (tonneaus) Steps & running boards Grille guards & bull bars Ladder & bed racks Truck toolboxes Bed storage & organizers Bed mats Floor liners Lights Strobes & warning lights Hitches & towing Shell & topper parts Fuses & wiring
- Tyger T3 Soft Tri-Fold Tonneau Cover — 6.9 ftAmazon
Covers and mats by brand for the 2026 GMC Sierra 2500 HD: BAKFlip covers UnderCover covers Roll-N-Lock covers Extang covers Husky Liners mats Michelin mats BedRug mats
2015–2019 GMC Sierra 3500HD → all accessories
Bed covers (tonneaus) Steps & running boards Grille guards & bull bars Ladder & bed racks Truck toolboxes Bed storage & organizers Bed mats Floor liners Lights Strobes & warning lights Hitches & towing Shell & topper parts Fuses & wiring
- Tyger T3 Soft Tri-Fold Tonneau Cover — 6.5 ftAmazon
Covers and mats by brand for the 2019 GMC Sierra 2500 HD: BAKFlip covers UnderCover covers Roll-N-Lock covers Extang covers Husky Liners mats Michelin mats BedRug mats
2007–2014 GMC Sierra 3500HD → all accessories
Bed covers (tonneaus) Steps & running boards Grille guards & bull bars Ladder & bed racks Truck toolboxes Bed storage & organizers Bed mats Floor liners Lights Strobes & warning lights Hitches & towing Shell & topper parts Fuses & wiring
- Tyger T3 Soft Tri-Fold Tonneau Cover — 6.5 ftAmazon
- Tyger T3 Soft Tri-Fold Tonneau Cover — 8 ftAmazon
- Gator ETX Soft Tri-Fold Tonneau Cover — 6.5 ftAmazon
Covers and mats by brand for the 2014 GMC Sierra 2500 HD: BAKFlip covers UnderCover covers Roll-N-Lock covers Extang covers Husky Liners mats Michelin mats BedRug mats
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Owner fit reports
Add yoursSwapped a shell, fit a tonneau, or measured your bed? Tell other owners what worked. Approved reports appear here.