Unit Price Calculator
Compare products by price per 100 g, 100 ml or item — find the best value.
About this calculator
Enter each product's price and size in whatever unit the label uses; the calculator converts everything to a common base — per 100 g, per 100 ml or per item — ranks them, and shows how much more the others cost.
Reading past the shelf label
Shelf unit prices exist, but they're inconsistent: per kilo on one shelf, per 100 g on the next, per litre for one brand and per 100 ml for another, and never across a supermarket and a warehouse club. Normalising to one base makes the comparison honest — and the percentages usually surprise: the “family size” is often only 5% cheaper per gram, and the multipack sometimes costs more per item than singles. The maths is division, but with the conversions done right (an ounce is 28.35 g, a pound 453.6 g, a US fluid ounce 29.57 ml), which is where in-aisle mental arithmetic fails. Two honest caveats the calculator can't see: the bigger pack only wins if you'll use it before it spoils, and price per unit says nothing about quality — compare like with like. The percentage calculator and discount calculator handle the promotions, and How to calculate percentages explains the arithmetic behind “+18%”.
Frequently asked questions
Can I compare grams with ounces?
Yes — weights are converted to grams, volumes to millilitres, and everything is shown per 100 g or 100 ml. Only weight-versus-volume can't be compared, and the tool says so.
What does 'per 100 g' mean?
The price of exactly 100 grams of that product at its pack price — the fairest base for comparing packs of different sizes. Items sold by count are compared per item.
Is the biggest pack always cheapest?
Usually per unit, not always — and only in practice if you'll finish it. The ranking shows the numbers; the fridge decides.
Does it work for sale prices?
Enter the price you'd actually pay. For 'buy 2 get 1 free', enter the total price and the total quantity of all three.