How to Measure Your Truck Bed

When ordering truck bed accessories for your pickup, it’s vital to know the exact dimensions of the bed to ensure a flawless fitment. Products like bed liners, bed mats, truck bed covers, bed rail caps, and more require accurate measurements. Otherwise, you may mistakenly order incorrect or ill-fitting parts. 

Luckily, measuring your pickup’s bed is quick and easy. However, doing so requires a few tips and tricks to ensure accurate data. In this RealSource feature, we cover how to measure your truck bed. 

Stay tuned for a step-by-step procedure and a straightforward bed length cheat sheet if you find yourself in a pinch.

So, what’s the point of pulling precise bed measurements, anyway? 

Though most pickup manufacturers employ standardized bed measurements—like a 6.5-ft. short bed and an 8-ft. long bed—these numbers aren’t always spot-on. Several manufacturers deviate from their advertised bed lengths by multiple inches. 

In addition, manufacturers typically offer up to three bed lengths per model, advertised as short beds, regular/standard beds, and long beds—tricky, right?  

While one or two inches of variance may seem negligible, these discrepancies can lead to serious fitment issues when installing truck bed accessories—and who likes returning parts? Knowing your truck's exact bed length, width, and depth is crucial to avoid purchasing incorrect parts and returns—regardless of how friendly and helpful RealTruck’s customer service team is. 

Measuring your truck’s bed isn’t difficult, though it requires several steps and a bit of patience. Follow along for a step-by-step guide to ensure accurate measurements every time. 

When measuring your truck’s bed, we recommend acquiring a few tools to make the process as smooth and accurate as possible. These include:

• A Quality Tape Measure: When measuring your truck’s bed, you’ll need a tape measure long enough with measurements in your preferred units (metric or imperial). We recommend a proper tape measure for this process—leave the wife’s sewing tape measure inside.  

• Pen and Paper (or notes application): Whether you prefer your smartphone’s notes app or good old-fashioned pen and paper, having a method of jotting down measurements is always a good idea. Doing so provides a reference point for future accessory purchases. 

• A Friend (optional): While not required, having an extra set of hands to hold one end of the tape measure is always preferred, especially when taking interior bed measurements. 

Now, let’s get to the meat of this article—measuring. This process isn’t complicated, though it’s easy to pull incorrect measurements if you aren’t aware of the proper ways to measure, i.e., where to start and stop. 

To begin, let’s measure the width of your truck’s bed. Begin by placing the tang of your measuring tape flush against the driver's or passenger's front of the bedside, near the bulkhead. If you have a friend, have them hold the tang of your tape measure securely against the bedside and stretch the tape to the other bedside. Record this measurement in your preferred units. 

Moving on to length, position the tape measure's tang flush against the bulkhead. Once again, if you have a partner, have them hold the tang in position as you stretch the tape measure along the bed rail to the inside edge of the top of your tailgate. Record this measurement in your preferred units. 

Finally, let’s measure your truck bed’s depth. While this value is less important, it’s wise to know when ordering products like tool boxes and chests, especially if you’re looking for an ultra-flush profile. 

Place the tang of your tape measure flush against the bed floor near one bedside. Stretch the tape vertically to the top edge of your pickup’s bedside. Record this measurement in your preferred units. Remember to measure from the tallest point of the truck’s bed floor, as most truck beds have ridges from drainage and cargo security. 

If you’d rather not run outside with a tape measure or if you’re ordering a gift without direct access to the recipient's truck, check out our truck bed size chart. The following tables offer bed measurements for all the top North American pickups, including midsize, half-ton, and heavy-duty models. Measurements are for the 2026 model year. 

Measuring a truck bed for a tonneau cover requires more precision than simply pulling a general bed length with a tape measure. Tonneau covers are engineered to fit specific bed length and bed rail profiles, so accuracy is key. 

To measure for a tonneau cover, start by measuring the bed length at the top of the bed rails, not the floor. 

Place the tang of your tape measure flush against the front bulkhead at the rail and extend it straight back to the inside edge of the tailgate. This measurement will determine whether your truck requires a short, regular, or long bed tonneau cover. 

Next, note any bed rail accessories that could affect fitment, like bed rail caps, utility tracks, cargo management systems, tool boxes, or headache racks. Lastly, confirm whether your truck has a drop-in bed liner, as some tonneau covers require different clamp styles depending on the liner type. 

Truck toppers, also called camper shells, canopies, and caps, demand extremely accurate measurements, as they’re designed to match your bed’s exact dimensions and the profile of the cab. 

Begin by measuring the bed length at the rails, just as you would with a tonneau cover. Then, measure the width across the bed rails from outside edge to outside edge. This dimension is crucial, as toppers sit on top of the bed rails rather than inside the bed. Some also feature lips that extend down past the tops of the bed rails, making a precise fit vital. 

You’ll also want to measure the cab height at the rear window if you’re shopping for a cab-height or mid-rise topper. This measurement ensures a seamless roofline and proper clearance between the cab and topper. Since toppers are among the most vehicle-specific accessories on the market, accurate measurements aren’t just recommended—they’re non-negotiables. 

Measuring a truck bed for a tool box is all about understanding usable space rather than the overall bed size. 

Begin by measuring the width between the bed rails where the tool box will sit, then the distance between the wheel wells, as many crossover and chest-style tool boxes are designed to fit between them. This measurement ensures the box won't interfere with contours in the bed. 

Next, measure the depth of the bed from the bed floor to the top of the rails. This measurement helps determine how tall a tool box you can run without interfering with tonneau covers or rear visibility. If you’re planning to pair a tool box with a tonneau cover, confirm compatibility and measure accordingly. 

Bed liners and bed mats rely heavily on the interior dimensions of the bed, making accuracy especially important. 

For bed liners, measure the bed length at the bed floor, from the bulkhead to the inside edge of the tailgate. Then measure the width between the wheel wells, as this is the tightest point in the bed and often dictates liner fitment. Finally, measure the bed depth from the highest point on the bed floor to the top of the bedside. 

Bed mats are slightly more forgiving, but you’ll still want an accurate bed length measurement to ensure complete coverage—especially if your mat includes tailgate protection. Always measure from the bed floor, not the rails, when shopping for liners and mats. 

Even though measuring a truck bed is straightforward, there are a few common mistakes that can throw off your results and lead to incorrect purchases. 

One of the most frequent errors is measuring from the outside of the tailgate rather than the inside edge. This mistake can add several inches and result in ordering the wrong product for the wrong bed length. Another common mistake is measuring the bed floor when the product requires measurements at the rail, or vice versa. 

Failing to account for drop-in liners, bed rail caps, or factory cargo management systems can also lead to incorrect results. These accessories can alter usable dimensions and affect how aftermarket parts mount or fit. Lastly, relying solely on the manufacturer’s advertised dimensions can throw off fitment, as most manufacturers round bed measurements to the nearest foot or to the nearest six inches. 

Manufacturers typically round bed sizes to the nearest half-foot for marketing purposes. A “6.5-ft. bed” may actually measure closer to 6 feet 7 inches or 6 feet 6 inches, depending on the brand and model year. These discrepancies are common, which is why measuring your specific truck is always recommended.

For most truck bed accessories, accuracy within ¼ inch is ideal. Products like tonneau covers, toppers, and bed liners are designed with tight tolerances, and even minor variances can affect fitment, sealing, and installation.

Manufacturer specs are helpful for general reference, but they shouldn’t replace physically measuring your truck—especially if it’s been modified or includes accessories like liners, bed rail caps, or cargo systems. Measuring ensures compatibility and minimizes returns.

It depends on the product. Bed liners and mats rely on floor-level measurements, while tonneau covers and toppers typically require rail-level measurements. Always check the product’s requirements before measuring.

Yes. Even when a truck retains the same name and model, manufacturers often tweak bed dimensions between generations or refreshes. Always measure your truck rather than assuming it matches a previous model year.

For additional information on measuring your truck bed, check out our comprehensive video guides. 

• How to Measure Your Truck Bed

• How to Measure your Truck Bed for a Tonneau Cover

And as always, shop RealTruck for all your top truck bed accessories. At RealTruck, we’re more than just a retailer—we’re a manufacturer of all your favorite high-end parts. Shop some of RealTruck’s in-house brands for the best quality and support, like Superlift suspension systems, Go Rhino® bumpers and steps, BAK® truck bed covers, and BedRug® bed liners and mats.