Unit price comparison

Which package is actually cheaper per ounce, litre or item.

Enter each package's price and size. Mixed units are converted automatically, so grams and kilograms compare correctly.

Best value
Bulk

$5.00 per kg — 28.4% cheaper than the worst option

Ranked

OptionPriceSizePer kgvs best
Bulk ✓$12.502.5 kilograms$5.00
Family size$5.991 kilograms$5.99+19.8%
Small$3.49500 grams$6.98+39.6%

How it works

Unit price is total price divided by total quantity. The only difficulty is that packages are deliberately sized to make that division awkward — 375 g against 1.2 kg, 6 rolls against 9 double rolls.

unit price = price ÷ quantity (in a common unit)

Bigger is not always cheaper

The “bulk discount” is a strong convention, not a rule. Promotions, loss-leaders and multi-buys regularly make the small pack cheaper per unit, and studies of supermarket shelves find the large size costs more per unit surprisingly often. The arithmetic takes ten seconds and is worth doing.

Unit price is not the whole answer

Cheaper per gram is worthless if half of it spoils. For perishables, weigh the unit price against what you will realistically use. For storage-hungry items, the shelf space has a cost too.