Double Wall Cardboard Boxes 18x18x20 inch (457 x 457 x 508 mm)

Measure the item at its widest points, add room for padding (a centimetre or two for soft goods, about 5 cm each side for fragile items), then choose the smallest box that fits.

Box sizes are normally given as the inside measurement. The outside is a few millimetres bigger because of the board, so allow for that if you are close to a postage limit.

Our single wall boxes are rated for 5 to 10 kg and our double wall boxes for 10 to 20 kg. Above that, use a smaller double wall box or split the load.

Single wall for everyday parcels up to 10 kg. Double wall for heavier loads (10 to 20 kg), fragile or valuable goods, long journeys, pallets and storage under other boxes.

FEFCO 0201 is the standard code for the most common box style: four flaps top and bottom, with the outer flaps meeting in the middle. It is what most people picture as a cardboard box.