How to measure a package for shipping

The three measurements

1. Length: the longest side.
2. Width: the next longest side.
3. Height: the remaining side.

Measure to the nearest inch (round up if you are between marks). Include bulge from tape or a padded envelope. Do not measure the item inside the box.

Girth (when a form asks)

Girth is usually 2 × width + 2 × height (the distance around the parcel perpendicular to length). Some oversize rules use length + girth. If Oshippy asks for L×W×H only, provide those; the carrier applies girth math when needed.

Soft packs and mailers

Lay the packed mailer flat. Measure the rectangle it actually is, not the unfilled bag size on the box of mailers. Overstating size can make postage worse; understating it can create an adjustment.

Large cubes: run the inches through the DIM weight calculator, then compare shipping rates.