GMC · Full-size heavy-duty pickup
GMC Sierra 2500HD bed dimensions & sizes by year
Buying a tonneau cover and not sure it'll fit? Pick your model year to get the exact bed length of your Sierra 2500HD in inches — plus the covers built for it. No guesswork, no wrong-size returns.
Find your bed size in 10 seconds
The GMC Sierra 2500HD has come in 5 bed lengths across 2005–2026:
Select your year above for the exact bed length that fits your truck.
Not sure which bed you have?
Two Sierra 2500HDs from the same year can have different beds depending on cab. Don't trust the badge — measure it. It takes 30 seconds and saves a return.
- 1
Close the tailgate.
- 2
Put a tape measure on the bed floor against the bulkhead (the wall behind the cab).
- 3
Measure straight back to the inside of the closed tailgate.
- 4
Match that number to a bed length above — covers are sold by category (5.5 ft, 6.5 ft, 8 ft…), so round to the nearest one.
Sierra 2500HD bed sizes & specs, year by year
Sierra 2500HD · T1 HD
| Bed | Length | Inches | Cabs | |
|---|---|---|---|---|
| 6.9 ft | 6'9" | 82.2" | Double Cab, Crew Cab | Covers → |
| 8.2 ft | 8'2" | 98.3" | Regular Cab, Double Cab, Crew Cab | Covers → |
- Cab styles
- Regular Cab, Double Cab, Crew Cab
- Drivetrain
- RWD, 4WD
- Max towing
- 22,500 lb
- Max payload
- 3,979 lb
- MSRP from
- $47,900 (launch)
Engines (2)
- 6.6L L8T V8 (gas) 401 hp · 464 lb-ft · Gas
- 6.6L Duramax L5P V8 turbo-diesel 445 hp · 910 lb-ft · Diesel
Standard bed grew to 6'9" (82.2") and long to 8'2" (98.3") - common fitment confusion vs older 6.6 ft HD beds. Available MultiPro tailgate. Regular Cab = 8 ft only. 2500HD is SRW only. Refresh for 2024. Allison 10-speed on diesel.
Sierra 2500HD · K2XX HD
| Bed | Length | Inches | Cabs | |
|---|---|---|---|---|
| 6.6 ft | 6'7" | 78.7" | Double Cab, Crew Cab | Covers → |
| 8 ft | 8'2" | 98" | Regular Cab, Double Cab, Crew Cab | Covers → |
- Cab styles
- Regular Cab, Double Cab, Crew Cab
- Drivetrain
- RWD, 4WD
- Max towing
- 18,100 lb
- Max payload
- 3,534 lb
Engines (3)
- 6.0L Vortec V8 (gas) 360 hp · 380 lb-ft · Gas
- 6.6L Duramax LML V8 turbo-diesel (2015-2016) 397 hp · 765 lb-ft · Diesel
- 6.6L Duramax L5P V8 turbo-diesel (2017-2019) 445 hp · 910 lb-ft · Diesel
Extended renamed Double Cab. Standard box ~6.6 ft / 78.7" (retailers label 6'7"). Regular Cab = 8 ft only. SRW only. L5P Duramax (445hp/910) from 2017.
Sierra 2500HD · GMT900 HD
| Bed | Length | Inches | Cabs | |
|---|---|---|---|---|
| 6.6 ft | 6'7" | 78.9" | Extended Cab, Crew Cab | Covers → |
| 8 ft | 8'2" | 97.8" | Regular Cab, Extended Cab, Crew Cab | Covers → |
- Cab styles
- Regular Cab, Extended Cab, Crew Cab
- Drivetrain
- RWD, 4WD
- Max towing
- 17,800 lb
- Max payload
- 4,192 lb
Engines (3)
- 6.0L Vortec V8 (gas) 360 hp · 380 lb-ft · Gas
- 6.6L Duramax LMM V8 turbo-diesel (2007.5-2010) 365 hp · 660 lb-ft · Diesel
- 6.6L Duramax LML V8 turbo-diesel (2011-2014) 397 hp · 765 lb-ft · Diesel
Standard box is ~6.6 ft / 78.9" (NOT 6.9 ft - that arrived with T1). Regular Cab = 8 ft only. SRW only.
Sierra 2500HD · GMT800 HD (Classic)
| Bed | Length | Inches | Cabs | |
|---|---|---|---|---|
| 6.5 ft | 6'6" | 78.7" | Extended Cab, Crew Cab | Covers → |
| 8 ft | 8'1" | 97.6" | Regular Cab, Extended Cab, Crew Cab | Covers → |
- Cab styles
- Regular Cab, Extended Cab, Crew Cab
- Drivetrain
- RWD, 4WD
- Max towing
- 12,000 lb
- Max payload
- 4,200 lb
Engines (4)
- 6.0L Vortec V8 (gas) 300 hp · 360 lb-ft · Gas
- 8.1L Vortec V8 (gas) 330 hp · 450 lb-ft · Gas
- 6.6L Duramax LLY V8 turbo-diesel (2005) 310 hp · 605 lb-ft · Diesel
- 6.6L Duramax LBZ V8 turbo-diesel (2006-2007) 360 hp · 650 lb-ft · Diesel
Final GMT800 HD, sold as '2500HD Classic' for 2007. SRW only on 2500HD. Bed inches vary by source - flagged verify.
What fits in a Sierra 2500HD bed
Bed length in inches only means something once you know what it swallows. Here's how the loads people actually haul line up against every Sierra 2500HD bed on record.
| Load | Needs | 6.9 ft · 82.2" | 8.2 ft · 98.3" | 6.6 ft · 78.7" | 8 ft · 98" | 6.5 ft · 78.7" |
|---|---|---|---|---|---|---|
| 4×8 ft sheet of plywood or drywall | 96" | Tailgate down | Fits, tailgate up | Tailgate down | Fits, tailgate up | Tailgate down |
| 8 ft 2×4s and trim lumber | 96" | Tailgate down | Fits, tailgate up | Tailgate down | Fits, tailgate up | Tailgate down |
| Full-size dirt bike | 85" | Tailgate down | Fits, tailgate up | Tailgate down | Fits, tailgate up | Tailgate down |
| Adult mountain bike, wheels on | 70" | Fits, tailgate up | Fits, tailgate up | Fits, tailgate up | Fits, tailgate up | Fits, tailgate up |
| Two-person truck bed tent | 60" | Fits, tailgate up | Fits, tailgate up | Fits, tailgate up | Fits, tailgate up | Fits, tailgate up |
| Standard 48×40 in shipping pallet | 48" | Fits, tailgate up | Fits, tailgate up | Fits, tailgate up | Fits, tailgate up | Fits, tailgate up |
"Tailgate down" assumes the roughly 18 inches a dropped tailgate adds on a typical pickup — measure yours before you count on it, and strap anything that overhangs. Width is the other half of the answer: a 48-inch sheet only lies flat on the bed floor when the wheel wells are more than 48 inches apart, otherwise it rides on top of the arches. For cubic feet of mulch, soil or gravel, run your dimensions through the bed volume calculator.
Volume is one limit, weight is the other. Check your Sierra 2500HD's real payload → · what it can actually tow →
More Sierra 2500HD specs
Bed size is one number among several. These carry the rest of the reference data for this truck specifically.
Other trucks with a Sierra 2500HD-size bed
Cross-shopping, or checking whether a cover you already own could move to another truck? These pickups come in a bed within two inches of a Sierra 2500HD bed.
- Chevrolet Silverado 1500
- Chevrolet Silverado 2500HD
- Chevrolet Silverado 3500HD
- Ford F-150
- Ford F-250 Super Duty
- Ford F-350 Super Duty
- Ford Ranger
- GMC Sierra 1500
Same length still isn't the same cover — rail height and bed-rail profile differ by truck. Confirm with the fitment checker before you buy or swap.
Tonneau covers that fit the Sierra 2500HD
Not sure a cover will fit? Run the Sierra 2500HD fitment checker → for your bed length, the cover types that fit, and any Sierra 2500HD-specific gotchas.
Hands-on Sierra 2500HD cover reviews are landing soon. In the meantime, browse vetted, correctly-sized options for your bed:
Sierra 2500HD bed size — frequently asked
What bed sizes does the GMC Sierra 2500HD come in?
The GMC Sierra 2500HD has been offered with 5 bed lengths: 6.9 ft (82.2"), 8.2 ft (98.3"), 6.6 ft (78.7"), 8 ft (98") and 6.5 ft (78.7"). The exact bed on your truck depends on its model year and cab — choose your year above to see which covers fit.
How do I measure my Sierra 2500HD bed length?
Measure the inside floor of the bed, from the bulkhead (the wall behind the cab) to the inside of the closed tailgate. Round to the nearest standard size — tonneau covers are sold by bed-length category (e.g. 5.5 ft, 6.5 ft, 8 ft), not the exact inch.
What bed size is the newest Sierra 2500HD?
The current Sierra 2500HD (2020–present) comes with 6.9 ft (82.2") and 8.2 ft (98.3").
Will a tonneau cover from an older Sierra 2500HD fit a newer one?
Not necessarily. Covers are matched to a specific generation and bed length, and both the bed length and the rail design can change between generations. Always match your exact model year and bed size before buying — the year-by-year table below shows where the Sierra 2500HD changed.
Will a 4×8 sheet of plywood fit in a Sierra 2500HD?
Yes — the longest Sierra 2500HD bed on record is 98.3", so a full 4×8 sheet lies flat with the tailgate closed. Width matters too: a 48-inch sheet only lies flat on the floor if the gap between the wheel wells is wider than 48 inches — on mid-size trucks it rides on top of the wheel arches instead.
What's the difference between the short and long bed Sierra 2500HD?
Across the model's history the beds run from 78.7" to 98.3" — a difference of 20 inches of usable floor. The longer bed hauls more and takes longer sheet goods, the shorter bed is easier to park and turn. They take different tonneau covers, so the bed you have decides which cover part number you order.
How much can a Sierra 2500HD tow?
Properly equipped, the Sierra 2500HD has been rated up to 22,500 lb across the generations on this page, with a maximum payload of about 4,200 lb. Those are best-case figures for a specific engine, cab and axle combination — your truck's door-jamb sticker and owner's manual are the numbers that count. Run them through the towing and payload calculators to see what's actually left for a trailer once passengers and gear are on board.
What cab configurations does the Sierra 2500HD come in?
The Sierra 2500HD has been offered as Regular Cab, Double Cab, Crew Cab and Extended Cab. Cab choice is what usually decides bed length — a bigger cab on the same wheelbase means a shorter bed, which is why two trucks from the same year can need different covers.
Does a tonneau cover on a Sierra 2500HD improve gas mileage?
A little, and only at highway speed. Independent testing puts the gain on a typical pickup at roughly 1–2%, which is real but small — on most Sierra 2500HD trucks that's a few dollars a tank, not a payback plan. Buy a cover for the dry, locked, secure bed; treat the mileage as a bonus.
