How to Measure a Box

Whether you're shipping items for your business, sending a gift to a friend or packing for a move, choosing the right box sizes is essential. Accurate box measurements help ensure cost-effective shipping, space-efficient storage and safety for your items in transit.

Guessing your box sizes could put your goods at risk — or leave you paying for empty space. You and those receiving your packages deserve better, so we've created these step-by-step box measurement instructions to help you pick and pack the perfect packaging every time.

Step 1: Gather Your Tools

To measure your box, you'll need the following:

A tape measure or ruler
A note-taking device or paper and pen
A calculator

Step 2: Understand Box Dimensions

Before starting, you need to understand what to measure. For packaging, you'll need to find the size of the space inside the box — this is its volume.

Volume is the product of a box's length, width and depth. Assuming you have a rectangular box, these dimensions refer to:

Length: The longest side when you look down at the top of the box.
Width: The shorter side when looking down at the box. Some people refer to this dimension as breadth, but width is the standard term.
Depth: The distance between the top of the box (with closed flaps) and the bottom of the box. Some people refer to depth as height — the two are generally interchangeable.

If you have a tall box, the depth or height will be the longest measurement. If you have a long box like a shoe box, the depth and width will be much smaller than the length. When recording box dimensions for shipping or orders, we always present them as length x width x depth (L x W x D). Whether you use depth or height, the order remains the same (L x W x H).

Step 3: Take Your Measurements

Now, you're ready to measure your box dimensions. To do so:

Lay the box flat if possible for easier measurement. If you're measuring a folded, standing box, measure the inside dimensions.
Note down each dimension as you go, rounding up to the nearest inch or the nearest centimeter if you need more precision.
Measure the length from end to end with your tape measure or ruler.
Turn the box 90 degrees to measure the width.
Measure the depth. Keep your measuring tool perpendicular to the box's base to avoid skewing your measurement.

Step 4: Calculate the Box Volume

Armed with accurate measurements, you can run the box volume calculation to understand how much space your box has inside. The formula is simple — just plug L x W x D into your calculator, and the result is your box volume in cubic inches.

For example, if your rectangular box has a length of 8 inches, a width of 6 inches and a depth of 4 inches, your box's volume is 192 cubic inches.

If your box is a cube, with length, width and depth all equal to 12 inches, your box's volume is 1,728 cubic inches.

Box Measurement Guide FAQs to Avoid Common Mistakes

While measuring a box can be simple when you know what to do, some packages can prompt extra questions and concerns. This section will help you handle the trickier cases and avoid common pitfalls.

Why Measure Inside the Box?

Measuring the inside of the box is important because this is where your items need to fit. The thicker the box material, the farther the external dimensions will exceed the internal dimensions.

You could choose a box that's too small on the inside by working with the external measurements. If you're ordering boxes, the industry standard is to use internal measurements, so you should order according to that standard to get what you're looking for.

When Should I Measure the Outside of a Box?

Carriers often use external box measurements to determine shipping fees, so it's safest to use the larger external dimensions when you measure a box for shipping cost estimations. External measurements are also helpful for working out how many boxes can fit in a space like a storage unit or logistics vehicle.

Where Can I Measure My Box?

Always place a box on a stable, flat surface before measuring it. If your surface is soft or uneven, this could distort your measurements.

What if My Box Is an Odd Shape?

The best practice for measuring boxes with irregular shapes is to measure each dimension in a straight line from the farthest points. This means taking the length and width from the farthest opposite compass points on the box's base or top and the depth from the tallest point to the bottom. These are the maximum dimensions relevant for shipping calculations and storage space planning.

That said, you'll also need to account for the shortest and narrowest points when working out whether an item can fit, so pay attention to the box's shape as much as its size if you're choosing a box for packaging. When ordering a box, always consider whether these minimum internal dimensions can accommodate the item you want to package at its tallest and widest points.

Does Box Material Matter When Measuring?

Yes. Thicker materials, like double-wall corrugated paperboard, have more variation between their inside and outside measurements. This makes it even more important to use the minimum dimensions when ordering boxes. Check whether an item will fit inside and use the maximum dimensions when planning for storage space and shipping costs.

If you're ordering boxes, you also need to consider the material's strength. Double-wall corrugated paperboard is ideal for heavier goods or items needing extra protection, while single-wall corrugated paperboard can work well for lighter items.

Get the Boxes You Need From Neway Packaging

Whether you're packing for a customer, a friend or yourself, precise box measurement is crucial. By following our tips for measuring boxes accurately, you can feel confident about getting your dimensions right every time. And if you need a supplier who cares about your packaging as much as you do, partner with Neway Packaging to make every package a perfect fit.

With over 50 years in the packaging industry, our team knows how to get your boxes right. We supply boxes in every size to meet your unique needs. Along with our extensive range of ready-to-ship stock boxes, we can make custom containers to your size and shape specifications and print them with your branding or design.

If you prefer making your boxes in-house, you can ensure precision and efficiency with our MAKE-N-SHIP™ box-making machine or count on our packaging machinery professionals to maintain or repair your existing machines.