Unit price is the cost per standard measure, such as per 100 grams, per litre or per item. Comparing unit prices lets you see which product is genuinely cheaper regardless of pack size.

Is the bigger pack always cheaper?

Not always. Sometimes a larger pack has a higher unit price than a smaller one, and a special can still be dearer per unit than another product. Comparing unit price reveals the real value.

How do I compare different sizes?

Divide each product price by its size to get the price per unit, then compare. This calculator does it instantly for two or three products so you can decide at the shelf.

Grocery Unit Price Calculator

This calculator helps you cut through confusing supermarket pricing by working out the true unit price of grocery products, the cost per 100 grams, per 100 millilitres, or per 100 items, so you can see which option is genuinely cheaper regardless of pack size or a flashy special. You enter the price and size of two products, and optionally a third, using whatever measure is printed on the label, grams, millilitres or a count of items. The calculator instantly divides each price by its size and shows the unit price for every product side by side, then names the best value option at a glance. This matters because a bigger pack is not always cheaper per unit, and a special offer can still work out dearer than an everyday-priced alternative once you compare like with like. To get an accurate result, enter each product's size using the same unit of measure, for example grams for both products or millilitres for both, since comparing grams against millilitres will not give a meaningful answer. Use this tool at home before you shop, or on your phone at the shelf, whenever two products look similar but come in different pack sizes, so you can stop guessing and make a quick, confident decision that adds up to real savings on your weekly grocery bill over time.

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Product A

Price

Size (grams, ml or items)

Product B

Price

Size (grams, ml or items)

Product C (optional)

Price

Size (grams, ml or items)

best value option, by price per 100 units

Product A-

Product B-

Product C-

Unit price is shown per 100 units of size, so compare products measured the same way, for example both in grams or both in millilitres. The lowest unit price is the better value, regardless of pack size or specials.

How it works

The calculator divides each product price by its size and multiplies by 100, giving the price per 100 grams, millilitres or items, depending on how you measured. Putting these side by side shows which product genuinely costs less for the same amount, cutting through the larger pack that is not actually cheaper or the eye-catching special that still loses on value.

Worked example

Product A at $4.50 for 500 grams is 90 cents per 100 grams. Product B at $7.00 for 900 grams is about 78 cents per 100 grams. Despite the higher sticker price, Product B is the better value per unit, which the calculator makes obvious at a glance.

Related calculators

Cost Per Use Calculator: value over a product life.
Discount Calculator: work out a discount.
Grocery Budget Calculator: plan a grocery budget.
Percentage Calculator: percentages.

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