This compares two products by their price per unit — the number that actually determines the better deal, which the sticker price or package size alone often does not.
How it works
Each product’s price is divided by its quantity, giving a price per unit for both — the same figure a shelf’s “price per 100g” label shows, computed directly from what you enter rather than trusted from a label that might use a different base quantity for two different package sizes.
Why the bigger package isn’t automatically the winner
$3 for 500g works out to $0.006 a gram; $5 for 750g works out to about $0.00667 a gram — the smaller, cheaper package is actually the better deal per unit, even though the second one has more product and a lower unit-price label position on some shelves. This is precisely the comparison a quick glance at two price tags gets wrong.
How to use this calculator
- Enter each product’s price and quantity.
- Make sure both quantities are in the same unit — grams against grams, not grams against pounds.
- Read which one wins per unit, and by how much.
Frequently asked questions
What if the two products are in different units, like grams and ounces?
Convert one to match the other first — the length & weight converter on this site handles that exactly — since this calculator assumes both quantities are already in the same unit and doesn’t guess a conversion for you.
Why might a store’s own “per 100g” label disagree with this calculator?
Rounding, mostly — shelf labels are often rounded to fewer decimal places than this calculator shows, which can occasionally flip which of two very close options looks cheaper at a glance.
Does a lower unit price always mean the better choice?
For pure value on the money spent, yes — but this calculator doesn’t know about quality, freshness, whether you’ll actually use the larger size before it spoils, or other reasons a shopper might reasonably prefer the “worse” unit price.
What does it mean if the two unit prices are exactly equal?
A genuine tie — neither package is the better financial deal, and this calculator says so plainly rather than arbitrarily picking a “winner” between two identical unit prices.
Can I use this for anything other than groceries?
Yes — any two options priced by quantity work the same way, from bulk cleaning supplies to fabric sold by the metre.
