Why price alone doesn't tell you the better deal
A $5.99 product isn't automatically worse than a $3.49 one — it depends entirely on how much you're getting. The only fair comparison is price per a common unit of quantity, which usually means converting first, since shelf labels rarely use matching units.
Store Brand: $3.49 for 32 oz Name Brand: $5.99 for 2 lb (32 oz) 32 oz × 28.3495 g/oz = 907.18 g Store Brand: $3.49 ÷ 907.18g × 100 = $0.38 per 100g 2 lb × 453.592 g/lb = 907.18 g (the same weight, different units) Name Brand: $5.99 ÷ 907.18g × 100 = $0.66 per 100g Both products are actually the same weight — 32 oz and 2 lb are identical — so this comparison comes down to price alone once the units match: the Store Brand is the clearly better deal, even though "$3.49" and "$5.99" don't immediately look comparable side by side.
Only compare within the same category
Price per ounce only means something when you're comparing two things measured by weight. It's meaningless to compare a weight-based price against a volume-based or count-based one — you can't fairly weigh a $/lb against a $/item. This calculator automatically groups products into Weight, Volume, and Count, and only ranks products against others in the same group.
Supported units
| Category | Units | Compared as |
|---|---|---|
| Weight | oz, lb, g, kg | Price per 100g |
| Volume | fl oz, ml, L, gal (US) | Price per 100ml |
| Count | ct, each, ea, item, unit, pc | Price per item |
"gal" refers specifically to the US gallon (3.785 liters), not the imperial gallon used in the UK and some other countries, which is a different, larger unit.
Frequently asked questions
How do you calculate unit price?
Divide the price by the quantity, converting to a common unit first if the products use different units. $3.49 for 32 oz works out to about $0.38 per 100 grams once converted — that figure is what you compare across products, not the sticker price.
Why isn't the cheaper-looking price always the better deal?
A lower sticker price on a smaller package can easily cost more per ounce than a pricier, larger one. The only way to know is to compare price per the same unit of quantity, not price per package.
Can I compare a product sold by weight against one sold by volume?
Not meaningfully — weight and volume measure different things, and a $/lb figure can't be fairly ranked against a $/L figure. This calculator keeps weight, volume, and count products in separate groups so it never produces a misleading cross-category comparison.
Does this work for multi-packs, like a 12-pack of bottles?
Yes — enter the total quantity across the whole pack. For 12 bottles of 16 oz each, enter 192 as the quantity (12 × 16) with unit "oz," rather than entering 12 with unit "bottle."