Dimensional Weight Calculator — See the Box Size That Stops the Overcharge

Field notes

The calculator models the relationship between parcel volume, a carrier divisor, actual scale weight, and the resulting chargeable figure. It also applies carrier-specific rounding rules and exposes a reverse threshold: the largest box that still bills on actual weight. The page separates standard courier calculations from Royal Mail’s format bands and leaves Evri figures unpublished where it says the relevant divisor is not clearly available. Carrier values are explicitly marked as unverified before launch.