CalcOak

Parcel Size and Girth Checker: measure length plus girth and test your box against carrier limits

Enter the three outside dimensions of the box to check it. Weight is optional but needed for the weight limits.

How to use this checker

Measure the outside of the packed box along its three edges and type them into the length, width and height fields. Order does not matter: the checker treats the longest edge as the length and builds the girth from the other two, exactly as the carrier does. Pick inches or centimetres, add the packed weight if you have it, and the girth, length plus girth and volume appear immediately in both unit systems. The "Swap" button converts the numbers you already typed, which is handy when a supplier quotes a carton in centimetres and your carrier quotes limits in inches.

Girth is a tape measure wrapped once around the box across its two smaller faces. Take a 24 × 18 × 12 in carton: the tape passes over an 18 in face, a 12 in face, another 18 in face and another 12 in face, so the girth is 2 × (18 + 12) = 60 in. Add the 24 in length and the length plus girth is 84 in. That single number is what most carrier rules are written against, which is why it sits in the highlighted card.

Why length plus girth matters

Sorting machines and delivery vans are built around a certain parcel envelope, and carriers price anything outside it aggressively. USPS adds a large package surcharge once length plus girth passes 108 in and stops accepting parcels above 130 in. UPS and FedEx apply an oversize charge from 130 in and refuse parcels over 165 in, and both also charge Additional Handling on boxes longer than 48 in, wider than 30 in on the second side or heavier than 50 lb. Those fees are often larger than the postage itself, so a box that is only an inch or two over a line can double the cost of a shipment.

The cheapest fix is usually a different box shape. A 50 × 12 × 12 in carton has a length plus girth of 98 in and picks up Additional Handling for being over 48 in long; packing the same items into a 36 × 16 × 14 in carton gives 96 in and no fee. If the contents cannot be repacked, splitting an order into two smaller parcels is frequently cheaper than one oversize one, and the volumetric weight calculator linked below shows how each option is billed. Use the table here to test a few candidate cartons before you commit to a pallet of them.

Further reading

Frequently asked questions

How do I measure girth on a box?+

Girth is the distance all the way around the box at its thickest point, measured perpendicular to the longest side. For a rectangular carton that is simply twice the width plus twice the height, using the two shorter sides. A 24 × 18 × 12 in box has a girth of 2 × (18 + 12) = 60 in, and adding the 24 in length gives a length plus girth of 84 in.

What happens if my parcel is over the length plus girth limit?+

Every carrier has a hard ceiling (130 in for USPS, 165 in for UPS and FedEx) above which the parcel is refused or has to move as freight. Below that ceiling there is usually a second threshold, 108 in for USPS and 130 in for UPS and FedEx, where the parcel still ships but picks up a large-package or oversize surcharge that can be more than the base postage.

Why does the checker flag Additional Handling when my box is within the limits?+

UPS and FedEx charge Additional Handling on parcels that are awkward to sort by machine even when they are well under the size ceiling: anything longer than 48 in, wider than 30 in on its second-longest side, or heavier than 50 lb. The fee is smaller than the oversize charge but still adds up across many shipments, so it is worth knowing before you print the label.

Does the orientation of the box matter?+

Not for the calculation, because the tool always takes the longest side as the length and uses the other two for girth, which is what the carrier does at the sorting hub. It matters a great deal when choosing a box, though: a long thin carton and a squat cube can hold the same volume yet land on opposite sides of a surcharge threshold.

Are the DHL limits the same as the US carriers?+

No. DHL Express publishes a per-piece maximum of 120 × 80 × 80 cm and 70 kg for its standard international service rather than a length plus girth figure. Anything larger is quoted as freight on a pallet. The checker converts your inputs to centimetres and tests each side against those figures.

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