Unit Price Comparison

Unit price is the primary comparison metric, but also consider: whether you will use all of the larger quantity before it expires, storage space, and whether you actually need that much. Bulk buying is only good value if you use what you buy.

Convert all quantities to the same unit before comparing. Divide grams by 1,000 to convert to kilograms, or multiply litres by 1,000 to get millilitres. Always use the same base unit for both products.

Not always. "Buy one get one free" is 50% off — often good value. "3 for 2" is 33% off. A seemingly large 20% discount on an already overpriced item may still be worse value than a competitor's regular price. Always calculate the unit price.