Question 1

How do I know which pack size is actually cheaper per unit?

Accepted Answer

Divide the total price by the quantity in the standard unit you want to compare (per gram, per oz, per ml, per tablet). The item with the lower price-per-unit is the better deal regardless of which size package is physically bigger. Many grocery stores print unit price on shelf labels, but often in different units — this calculator standardizes them for direct comparison.

Question 2

Is the biggest pack size always the best value?

Accepted Answer

No — this is a common supermarket illusion called 'bulk pricing bias'. Stores regularly price mid-size packs at better unit prices than large packs, especially during promotions. Studies from Which? (UK) and Consumer Reports (US) consistently find that the 'value size' is not always cheapest per unit. Always calculate.

Question 3

Does this calculator work for comparing different brands, not just sizes?

Accepted Answer

Yes — enter any product's price and quantity, regardless of brand. You can compare a 500g store-brand cereal at $2.49 against a 750g name-brand at $4.19, and immediately see which costs less per 100g.

Grocery Unit-Price Comparator

Item Comparison

Standard Size

Family Size