Enter the size and weight of what you ship. The sizer suggests the smallest mailer and box that fit, the Royal Mail size band the packed parcel falls in and its volumetric weight. Figures are a guide: check a sample with your product before a large order.
Parcel sizer
The size and weight of the item you are sending, before packing.
Size bands and the volumetric divisor of 5000 are common published figures and carriers change them. Check your carrier's current tariff. How sizing works