How to read supermarket specials: unit pricing explained

An example shopper (made up for this guide): One pack on the shelf has a bright special sticker. A bigger pack next to it is labelled "family size". The small pack you usually buy is in between. Which one should you take?

Three things matter: the unit price, how much you'll actually use, and how much you want to spend today.

1. Find the unit price on the ticket

The unit price is the price for a standard amount, such as per kilogram, per litre, per 100 g or per item. On the ticket it's shown next to the selling price.

The Unit Pricing Code covers prescribed grocery retailers: broadly, qualifying large grocery stores (more than 1,000 square metres of grocery-display space) and online grocery retailers selling the Code’s minimum grocery range, plus participating retailers. For covered goods, the display obligation applies when a selling price is displayed, subject to the Code’s exemptions. Required unit prices must be prominent, close to the selling price, legible and unambiguous. Coverage depends on the retailer, product and display—not every shop or advertisement. The Code has exemptions, including some goods, markdowns and promotions; it also exempts television, radio and similar online audio/video advertising. Smaller stores may participate, so size alone does not settle every case. See ACCC unit-pricing guidance, Code overview and the current Code, Schedule 1, clauses 3–12.

Shopping online? The ACCC suggests checking whether the site lets you sort by unit price.

2. Make sure you're comparing the same unit

One ticket may show the price per 100 g and another per kg. Convert them to the same unit first: a price per kg is 10 times the price per 100 g, because 1 kg = 1,000 g.

Fruit and veg can be priced per kg or per item. The ACCC shows a lemon priced both ways. Compare like with like.

3. Work out the comparison without a made-up price

Unit price per 100 g = selling price ÷ number of 100 g portions in the pack. Use the current ticket’s selling price; this guide does not supply fictional or market prices.

• A 500 g pack contains 5 portions of 100 g: divide its selling price by 5.
• A 2 kg pack contains 20 portions of 100 g: divide its selling price by 20.

The large pack contains four times as much. It has a lower unit price only if its selling price is less than four times the small pack’s selling price; equal multiples mean equal unit prices. Check both actual tickets. A lower unit price does not necessarily mean a lower total spend today.

Quantity-only illustration: a made-up household plans to use 400 g of uncooked rice this week—not a serving recommendation. A 500 g pack leaves 100 g uncooked; a 2 kg pack leaves 1,600 g uncooked. Those are quantities, not prices or guaranteed waste. Check storage, later use and today’s budget. Buy neither if you already have enough.

4. A special sticker is not a unit-price comparison

Compare a 400 g pack with a special sticker and a 500 g pack without one. Divide each current selling price by its number of 100 g portions: 4 for the first pack, 5 for the second. Compare the results in the same unit. Either pack could have the lower unit price; the sticker does not answer that question.

Use the lower unit price only after checking both products suit your household. Taste, dietary needs, available storage and total spend still matter. A sticker alone does not show the earlier selling price or how long it applied.

5. Multi-buys: will you use them all?

For a "2 for" deal, compare both total spend and unit price with buying a single item, and consider whether you will use the extra. For covered retailers and non-exempt groceries, the ACCC says same-item multi-buys require a unit price. Different-item bundles for one price are exempt; other Code exemptions can also apply. Do not assume every promotion must display a unit price.

Quick check: Would you buy the second one soon anyway?

6. "Was/now" specials

A "was" price is what the shop says the item used to cost. The ticket doesn't usually tell you how long it sold at that price. Use the unit prices you can compare on the shelf today.

7. Fresh food and waste

A low unit price only helps if you use the food. Bigger packs may suit things your household uses often and that keep. For fresh food, buying what's on your plan can help. See Meal planning for busy households and Cutting food waste at home: simple, practical steps.

The short version

• Find the unit price and check both tickets use the same unit.
• Unit price = selling price ÷ number of units (for example, 100 g portions).
• Compare across sizes and brands, not just the item with the special sticker.
• Weigh the unit price against how much you need and what you'll pay today.
• A special sticker alone doesn't prove a price drop.
• The biggest pack or the special isn't automatically the right choice.

Next step: Next time you shop, pick one item you buy regularly. Compare the unit price of two sizes and two brands, then decide based on how much you need.

We don't list prices here, because they change depending on where you are. Check the retailer's site for the current price where you are.