How to Measure a Truck Bed

Dustin Hawley | Feb 15, 2021

As a truck owner, there are many reasons you might want to know the size of your truck bed. The most obvious reason is if you need to determine its capacity for transport. Simply put, you want to know what you can carry before you attempt to move something too large.

how to measure a truck bed

Perhaps you are preparing to outfit your truck with some accessories. If you are considering purchasing a bed liner, toolbox, or tonneau cover, they will always require a proper fit. Eyeballing your bed or using the manufacturer’s stated size won’t always get you the desired results.

We have put together a brief guide on how to measure your truck bed correctly. We’ll begin with the basics before moving on to some specific applications and measurement techniques. Let’s get started.

Truck Bed Measurement Basics

Before we talk about measuring for accessories, let’s start with the basics: how to measure your truck bed’s dimensions. 

For starters, you’ll need at least a 10-foot or longer tape measure, along with a pencil and paper for documenting your measurements. A smartphone or pocket calculator may also be useful for more advanced calculations.

Measuring the Width of the Truck Bed

To make this measurement, position the tape right at the inside edge of the sidewall, or “bulkhead.” Keeping the tape measure straight, extend it to the opposite bulkhead’s inner edge, and write down your measurement.

Note that many pickup trucks have wheel wells that protrude into the sides of the bed. If you’re trying to lay something flat for transport, measure between the inside of the wheel wells instead.

Measuring the Length of the Truck Bed

Measuring the length of a truck bed is similar in practice to measuring the width. You’ll want to measure from the inside of the front bulkhead to the inside of the tailgate, keeping the tape straight and level to maintain accuracy. Again, you will want to write down the measurement.

Calculating Square Footage

To calculate your truck bed’s square footage, you’ll simply multiply the vehicle’s length by the width, in inches, and divide by 144. Here’s a quick example:

  • Assume a truck bed measures 48 inches in width by 96 inches in length.
  • We would calculate: 48 x 96 = 4,608.
  • We would then calculate: 4,608 ÷ 144 = 32, so our truck bed has an area of 32 square feet.

Calculating Cubic Yardage

In most cases, your primary concern regarding cargo in your truck is the weight rather than its total volume. Even so, it’s illegal in many areas to haul a load that’s piled up higher than the back of the tailgate, so in these instances, you’ll want to find the cubic yardage of your truck bed. You’ll need the square footage to do this, so begin by calculating that number.

Once you have determined this figure, measure your tailgate’s height from the bottom of your truck bed, and divide that number by 12, which will give you the truck bed’s height in feet. For instance, if your tailgate is 18 inches tall, you would write down “1.5”. Now, all of your units are in feet, so you simply have to calculate the volume and convert.

  • Assuming our previous truck bed in this example, 32 square feet at the height of 1.5 feet, would equal a volume of 48 cubic feet (32 x 1.5 = 48) 
  • To determine the cubic yardage, divide the cubic feet by 27. So we would calculate 48 ÷ 27 = 1.78 square yards.

Measuring for a Truck Bed Liner

Bed liner measurements are performed in the same way as standard measurements. All you need is a tape measure, a pencil, and some paper. Though the process is relatively simple, bear in mind that this will only get you the raw dimensions; it won’t tell you the truck bed’s shape or profile.

For this reason, most truck bed liners are designed for specific truck models. Truck beds can change from year to year, even between variants of the same model. The more information you have about your vehicle, the better fit you’ll achieve.

Measuring for a Tonneau Cover

Tonneau cover measurements are the same as standard measurements. Many truck beds don’t have round-numbered measurements, a short bed F-150 being a prime example. It has an advertised bed length of 67 inches, but the actual length is 67.1 inches. If you’re confused, there are plenty of online charts with actual bed lengths listed.

If we divide the length and width in inches by 12, it will provide us with measurements in feet. Tailgate liners and rail liners can also sometimes distort your measurements. Make sure you account for their thickness coming up with your numbers before you purchase your Tonneau cover.

Measuring for a Toolbox

When you shop for bed boxes, you’ll notice that there are two different length measurements. One is the distance between the top portion of the box (which sits on your rails), and the other is the width of the portion of the box that sits inside your truck bed. The smallest of the two numbers is the one you should be concerned with.

Height is another consideration. It’s fine to use a toolbox that’s shorter than your rails. It will simply leave a gap between the bottom of the box and the bottom of the bed. However, if the box is too tall, you won’t be able to secure it to your rails. Ensure that you are accounting for this measurement accordingly when deciding on a bed box.

Measuring for Nerf Bars or Running Boards

Nerf bar and running board measurements are a little bit different than standard measurements. For one, you don’t actually measure the length of the truck bed. Instead, you want to measure the distance from wheel to wheel.

There are two types of nerf bars. One of the types is cab length, meant only to help you get in and out of the vehicle and reach the top of the cab. The others are full length and extend as far as the rear wheel.

For safety purposes, you don’t want to measure the actual distance between your front and rear tires. Instead, measure the distance between the wheel wells, then round down to the nearest inch, providing plenty of clearance for your wheels to turn safely.


By now, you know everything you need to know on how to measure a truck bed for most general purposes. If you’d like to learn more, don’t close your browser! You can read more of our guides and learn more about taking care of your vehicle right here!

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