How unit price calculator Works
Why unit price beats price
Package sizes shrink while prices hold ("shrinkflation") — the only defense is normalizing to a unit. The 12 oz can at $1.99 (16.6¢/oz) vs the 25 oz bottle at $3.49 (14¢/oz) is invisible on the shelf and obvious per ounce. Stores legally print unit prices on shelf tags, but formats vary by store — a calculator that keeps the units consistent beats squinting at tags.
The bulk-size traps
Three regulars: (1) the warehouse "deal" that spoils before you finish it, (2) the bigger box whose unit price is actually worse (yes, that happens — always check), and (3) the multi-buy offer ("3 for $10") that usually just equals $3.33 each, no discount required. Unit price normalizes all three lies into one honest number.
Cost-per-use: the adult version
The same math scales up: a $90 appliance used weekly for 5 years is 35¢/use; a $90 night out is $90/night. Detergent per load, per-wear on clothes, per-hour on subscriptions — cost-per-use converts purchase anxiety into a number you can compare against the value you actually get.