Work out bulk buy saving instantly with clear inputs, formula shown and shareable results.
Bulk buying pays when the unit price falls and the stock gets used before it expires. Four months of supply is usually fine for household goods, but the months-of-supply figure is what turns a headline saving into a decision.
Bulk saving
bulk unit price = pack price / units; saving = 1 - bulk unit / normal unit; annual saving = difference x annual usage
When the item degrades, when storage is scarce, or when having more on hand simply increases consumption — a well-documented effect with snacks and cleaning products.
At household scale, rarely. But buying a year's supply ties up money that could clear a credit card balance at 20% interest.