What Is Dimensional Weight? Why Size Matters When Shipping

When shipping a package, weight isn’t the only thing that matters. Carriers also use something called dimensional weight, often called DIM weight, to calculate shipping costs. This is why a lightweight package can sometimes cost more than expected.

What Is Dimensional Weight?

Dimensional weight is a pricing method carriers use to account for the amount of space a package takes up in a truck or airplane. Large boxes—even if they’re light—take up valuable space, and DIM weight helps balance size and shipping efficiency.

Carriers calculate dimensional weight by using the package’s length, width, and height, then comparing that number to the actual scale weight. The higher of the two is what you’re charged for.

Why Size Matters

A box that’s too large can increase shipping costs significantly. Extra space inside the box means more materials, more room in transit, and higher fees—even if the item itself doesn’t weigh much.

How to Reduce Dimensional Weight Costs

• Use the smallest box that safely fits your item

• Avoid unnecessary padding or oversized packaging

• Let professionals choose the right box size

At Ship It – Bay & Beyond, we measure and pack items efficiently to help keep shipping costs as low as possible.

The Bottom Line

When it comes to shipping, size matters just as much as weight. Understanding dimensional weight helps you avoid surprises and ship smarter every time.