Shipping Calculator Lab

Methodology

Our calculators separate user measurements from assumptions so you can see exactly how a result is produced.

Calculation principles

• Dimensions use the outside of packed cartons unless a tool explicitly describes internal capacity.
• Unit conversions use fixed mathematical conversion factors.
• Counts of physical packages are rounded down for capacity or up for purchasing, as described on each tool.
• Carrier-specific limits and rates are never presented as live data.

Verification

Formula functions are tested with known examples, zero and boundary inputs, both measurement systems and independent hand calculations. Content is reviewed when a formula or assumption changes.

Reference sources

Carrier rules are not built into results unless the user enters them. The measurement and terminology guidance is checked against primary references, including UPS dimensional-weight guidance, FedEx dimensional-weight guidance, DHL volumetric-weight guidance and Maersk equipment guidance.

Method and reference links reviewed September 8, 2026.

Known limitations

Real loads are affected by carton compression, equipment tolerances, access space, dunnage, payload, regulations and provider rounding. These tools intentionally do not replace a carrier quote or loading plan.

Shipping terms used on this site

Chargeable weight

The comparison value used for billing after applicable weight and size rules are applied.

CBM

Cubic meters, a measure of three-dimensional shipment volume.

Girth

The distance around the two shorter dimensions of a parcel.

Payload

The maximum cargo weight equipment can carry, excluding its own tare weight.

Dunnage

Material used to secure, separate or protect cargo during transport.