UnitPrice

Which package is actually cheaper? Compare price-per-unit across sizes and units, on-device.

Unit pricing is regulated in many countries precisely because per-package prices are hard to compare on a shelf. The larger box is usually but not reliably cheaper, and the exceptions are common enough that shoppers assuming the rule lose money on them regularly.

The comparison gets genuinely difficult when units differ — one product priced per 100g beside another per item beside a third per litre. Normalising those by hand while standing in an aisle is where people give up and guess. Worth remembering that cheapest per unit is not always the right answer either, if the larger size expires before you finish it.