The box decides the bill, not the item.

Your package

Outside dimensions of the packed carton, in inches. Weight is per package.

Common questions

What is dimensional weight?

It is the weight a carrier assigns to the space your package takes up, so that a box of pillows does not travel for the price of a box of bolts. Take the cubic inches of the carton and divide by a number in the contract called the DIM divisor. The carrier then bills the greater of that figure and what the package actually weighs, rounded up to the next whole pound. A trailer runs out of room long before it runs out of payload, which is why the space is what gets priced.

What is a DIM divisor, and which one applies to me?

It is the constant that converts cubic inches into pounds, and it is the single most valuable number in a parcel agreement. A bigger divisor means a smaller dimensional weight and a cheaper bill. The published US domestic figure for the major carriers has been 139, but negotiated accounts routinely carry 166, 194 or 250, and the divisor can differ between ground and air on the same account. This page defaults to 139 and lets you change it, because the right answer is on your rate agreement rather than in any calculator.

Why is my shipping cost higher than the weight on the scale?

Because you are not being billed on the scale. If the carton prices above the goods, the dimensional figure wins and the difference is air you are paying to move. This page names that gap in pounds rather than leaving it as a ratio, because the number that changes a decision is how many pounds of nothing are on the invoice. A four pound item in a sixteen by twelve by ten inch carton bills at fourteen pounds at a 139 divisor: ten of those pounds are empty space.

What size box stops me paying for air?

Any box whose cube is below your actual weight multiplied by the divisor. The page works that ceiling out and states it in cubic inches, and where the footprint allows it, also as a packed height on the carton you already have. Sometimes the honest answer is that no height reaches it, because the length and width alone already price above the goods. In that case the page says so instead of telling you to pack a mug flat, since a smaller footprint is the only thing that would work.

Should I round the dimensions?

Usually yes, and the checkbox is on by default. Carriers measure each side and round it to a whole inch before multiplying, so a carton measuring twelve and a half inches on every side is cubed as thirteen. Rounding after the multiplication instead of before gives a different and smaller answer, which is how an estimate and an invoice end up disagreeing. Turn it off if your service prices on exact measurements.

What are the girth and surcharge warnings?

Girth is the strap-around measurement that parcel surcharge tables are written in: the longest side plus twice each of the other two. Above certain lengths and girths a package stops being ordinary and picks up additional handling, then a large package surcharge, then refusal as a parcel altogether. The page flags which band the carton falls in from its dimensions alone. It deliberately does not quote a dollar figure, because those amounts are rate card terms that change and would go stale here.

Does this work for several packages at once?

Yes, for identical ones. Each package is rated on its own and rounded up on its own, so the total is the per package billable weight times the count. That matters more than it sounds: adding the cubes together and dividing once would quietly lose the round up on every package, which is exactly the sort of small error that makes an estimate disagree with an invoice. If your cartons differ, run each configuration separately.

Is my data uploaded anywhere?

No account and no network requests. The arithmetic runs entirely in your browser and nothing about your packages is sent anywhere. The usage counter is a local, opt out tally of which features were used, never your dimensions or weights.

Are my numbers saved, and can I share them?

Your last entry is kept in this browser's local storage, so a refresh or a visit tomorrow restores it, and nothing is uploaded. Copy shareable link puts the same figures in the page's URL fragment, after the hash, so sending that link to a co packer or a 3PL rep opens this page with the identical package already worked out. A link takes priority over a saved draft when you open one.