GMC · Full-size heavy-duty pickup
GMC Sierra 2500HD bed size & length
Every Sierra 2500HD bed length in inches, generation by generation, from 2005–2026 — which cab each one comes with, and the tonneau cover size it takes.
2020–present · T1 HD
6.9 ft · 8.2 ft
2 beds offered
Which covers fit a Sierra 2500HD → Sierra 2500HD full specs →
Lengths are the inside floor measurement for the generation shown. Brochure names round hard — always measure your own bed before ordering a cover.
Sierra 2500HD bed size by year
The bed line-up moved during this model's run, so the year matters more than the badge. Find your generation below.
| Years | Generation | Bed | Length | Inches | Cabs |
|---|---|---|---|---|---|
| 2020–present | T1 HD | 6.9 ft | 6'9" | 82.2" | Double Cab, Crew Cab |
| 〃 | 8.2 ft | 8'2" | 98.3" | Regular Cab, Double Cab, Crew Cab | |
| 2015–2019 | K2XX HD | 6.6 ft | 6'7" | 78.7" | Double Cab, Crew Cab |
| 〃 | 8 ft | 8'2" | 98" | Regular Cab, Double Cab, Crew Cab | |
| 2007–2014 | GMT900 HD | 6.6 ft | 6'7" | 78.9" | Extended Cab, Crew Cab |
| 〃 | 8 ft | 8'2" | 97.8" | Regular Cab, Extended Cab, Crew Cab | |
| 2005–2007 | GMT800 HD (Classic) | 6.5 ft | 6'6" | 78.7" | Extended Cab, Crew Cab |
| 〃 | 8 ft | 8'1" | 97.6" | Regular Cab, Extended Cab, Crew Cab |
What cover size a Sierra 2500HD takes
Tonneau covers are sold by bed category, not by exact inches. Here is where each Sierra 2500HD bed lands — and every other truck in the same category, in case you are cross-shopping a used cover.
Measuring a Sierra 2500HD bed properly
Two minutes with a tape beats any chart, including this one. Covers are cut to the inside of the bed, so that is what has to be measured.
- 1
Close the tailgate
Measure with the tailgate up and latched. A bed measured with the gate down reads roughly 20 inches long and every cover ordered off that number comes back.
- 2
Measure inside, along the floor
Run the tape on the bed floor from the front bulkhead to the inside face of the closed tailgate. Not along the top of the rails, and not down the outside of the body — both read longer than the bed actually is.
- 3
Measure over a spray-in liner
If the bed is sprayed, measure over the coating. That is the surface the cover sits on. A drop-in plastic liner is a different matter — if its lip wraps over the top of the rail, it sits between the bed and the cover's clamps.
- 4
Round to the nearest category
Your tape will read something like 82.2" rather than a clean number. Covers are sold in categories, so match the category and then confirm the fit against your exact year.
Sierra 2500HD bed size — frequently asked
What bed sizes does the GMC Sierra 2500HD come in?
The 2020–present GMC Sierra 2500HD is offered with 2 beds: 6.9 ft (82.2") and 8.2 ft (98.3"). Earlier generations were not identical — the table below lists every generation, because a cover bought for the wrong one will not seal.
How long is the Sierra 2500HD bed in inches?
The 6.9 ft bed measures 82.2 inches along the floor, and it is the shortest of 2 on the current truck. Manufacturers round these in their brochures — a "5.5 ft" bed is rarely 66 inches exactly — so measure your own floor from the bulkhead to the closed tailgate before ordering anything cut to length.
How do I measure my Sierra 2500HD bed?
Measure inside the bed, along the floor, from the front bulkhead to the inside face of the closed tailgate. Do not measure the outside of the body, and do not include the tailgate when it is down. If a spray-in liner is fitted, measure over it, since that is the surface a cover clamps against.
What size tonneau cover fits a Sierra 2500HD?
Covers are sold by bed category, and the GMC Sierra 2500HD falls into these categories: 6.5 ft and 8 ft. Match the category to your own bed, then confirm the exact year and generation — bed rails, tie-down systems and cargo-management tracks change between generations even when the length does not.
Did the Sierra 2500HD bed size change over the years?
Yes. Across 2005–2026 the bed line-up changed between generations, and inside lengths moved even where the marketing name stayed the same. Go by your truck's year in the table below rather than by the badge, especially when buying a used cover.
Will a cover from a different Sierra 2500HD year fit mine?
Only if the bed length and the rail design both match. Length is the first check and the easiest to get right; the second is how the cover clamps, because a generation change often moves the rail profile or adds a factory cargo track. Check both before buying a used cover.
