Smart Shopping

Last updated May 2026

The one number that changes everything at the supermarket.

Unit pricing shows the cost per kg, per litre, or per 100g. It is mandatory in Australian supermarkets and it is the only reliable way to compare products of different sizes. Here's how to use it, and where it breaks down.

A jar of peanut butter costs $5.50. Another costs $9.50. Which is cheaper? You cannot answer that question without knowing the size. That is the point of unit pricing, and it is the most underused tool on every shelf in Australia.

What is a unit price?

A unit price is the cost per standard unit of measurement. For solids, that is usually per kilogram or per 100g. For liquids, per litre or per 100mL. It strips away the packaging, the brand design, and the size of the box, and tells you exactly how much you are paying for the product itself.

Unit pricing has been required by law in Australia since 2009 under the Trade Practices (Industry Codes, Unit Pricing) Regulations. Every supermarket shelf tag in the country must display it. The number is there. Most people just do not look at it.

When bigger is not cheaper.

The default assumption most shoppers carry is: buy the bigger pack, pay less per unit. This is often true. It is also often wrong, and the exceptions are not random. They follow patterns that are worth knowing about.

These examples use real products in different sizes. The unit price differences are real. Rows in bold are the cheapest option in each group.

Four of these five product groups break the "bigger is cheaper" rule. The 1L Coles olive oil costs $1.60/100mL while the 500mL bottle is $1.40/100mL, a 14% premium for buying bigger. The Weet-Bix 1.4kg "family pack" at $0.75/100g is more expensive per gram than the mid-size 1.12kg box at $0.71/100g. The Chobani multipack costs $1.25/100g, which is 50% more per gram than the 907g tub at $0.83/100g. And the Finish 160-pack ($0.43/tablet) costs more per tablet than the 110-pack ($0.38/tablet).

These are not obscure examples. They are products that sit on the shelf of every major supermarket in the country. Without checking the unit price, you would have no way to know.

Same product, different store, different price.

Unit pricing is not just useful for comparing sizes. It is essential for comparing the same product across retailers. The price differences on basic staples can be significant.

Chicken breast is the starkest example. ALDI sells it at $7.85/kg. Coles and Woolworths charge roughly $15.00/kg for their standard range. That is nearly double the price for the same cut. On a product you buy every week, that difference compounds quickly.

Harris Farm milk at $2.00 for 2L ($1.00/L) is nearly half the price of Coles and Woolworths at $3.55 ($1.78/L). These are not promotional prices. They are the everyday shelf price.

The tricks that break unit pricing.

Unit pricing is straightforward in theory. In practice, three common situations make it unreliable or invisible.

Specials that change the pack size, not the price.

A "new 150g pack" at $4.50 replaces a 175g pack at $4.50. The sticker price is identical. The unit price just jumped 16.7%. This is shrinkflation disguised as a product refresh. The old shelf tag disappears, so unless you remember the previous weight, the change is invisible. The unit price on the new tag is technically accurate, but there is nothing to compare it against.

Multi-buy deals where the unit price label does not update.

You see a "2 for $7" sticker on a product that normally costs $4.50 each. Good deal. But the unit price printed on the shelf tag often still reflects the single-item price. Some retailers update it, some do not, and the inconsistency means you cannot rely on the label alone during a promotion. You have to do the maths yourself: $3.50 per item, then divide by the weight.

Fresh produce priced "each" at one store and "per kg" at another.

Avocados at $2.50 each versus $9.00 per kg. Which is cheaper? It depends entirely on the size of the avocado, and you have no way to know without a scale. When one retailer prices by the item and another by weight, unit pricing comparison becomes physically impossible at the shelf. This is not an edge case. It is common across fruit, vegetables, bakery items, and deli products.

What the ACCC found.

The ACCC's Supermarkets Inquiry Final Report (February 2025) examined unit pricing in detail and found systemic problems with how it is implemented in practice:

• Labels are frequently too small to read. The font size on shelf tags, particularly in the unit pricing section, is often below what is legible for many shoppers, especially older Australians.
• Placement is inconsistent. The unit price may appear in different locations on the shelf tag at different retailers, and sometimes at different locations within the same store.
• Online listings often omit unit pricing entirely. Many supermarket websites and apps do not display unit pricing on product listing pages, requiring shoppers to click into individual product pages to find it. Some do not display it at all.
• Promotional pricing creates gaps. During promotions, the unit price on the shelf tag may not reflect the actual unit cost the shopper will pay.

The ACCC recommended reforms to the Unit Pricing Code of Conduct to address these gaps, including minimum font size requirements, mandatory online display, and updated promotional pricing rules. As of May 2026, those reforms are still being finalised.

The Australian rules.

The Unit Pricing Code of Conduct is a mandatory industry code under the Competition and Consumer Act 2010. It applies to grocery retailers with a selling area of more than 1,000 square metres. In practice, this covers every Coles, Woolworths, ALDI and Harris Farm store in the country.

Retailers must display the unit price on shelf labels, using standard units of measurement: per kilogram for items sold by weight, per litre for items sold by volume, and per unit for items sold individually (such as eggs). The unit price must be legible and in close proximity to the selling price.

The ACCC enforces compliance. The gap between the rule and the reality, as the February 2025 inquiry documented, is significant.

How Pinch helps.

Pinch normalises unit prices across Coles, Woolworths, ALDI and Harris Farm. When you add a product to your shopping list, you see the per-100g or per-litre price at every store, side by side. You do not need to do the division yourself, remember what the old size was, or squint at a shelf tag.

Because Pinch updates prices continuously and stores 52 weeks of history, you can also check whether a "special" is genuinely lower than the product's usual unit price, or whether it is an illusory discount on an inflated reference price.

Build your shopping list and compare the real cost at every store before you leave home. Free on iOS and Android.