Unit price calculator
Two sizes on the shelf and not sure which is the better deal? Pop in the price and pack size for each and we'll rank them.
Cheapest first
How it works
unit price = price ÷ pack size × standard amountEverything is converted to grams or millilitres first (1 kg = 1,000 g, 1 L = 1,000 mL), then shown per 100 g / 100 mL and per kg / L.
Worked example
Rice: a 1 kg bag is $3.20 and a 5 kg bag is $13.50. The 1 kg bag works out at $0.32 per 100 g, the 5 kg bag at $0.27 per 100 g – about 16% cheaper per gram.
Milk: 2 L for $3.10 is $1.55 a litre, while 3 L for $4.50 is $1.50 a litre. Close, but the bigger bottle edges it – if you'll drink it in time.
Common questions
What is a unit price?
It's the price for a standard amount – usually per 100 g, per kg, per 100 mL, per litre or per item. Australian supermarkets have to show it on the shelf label, which makes it easy to compare different pack sizes.
Is the bigger pack always cheaper?
No. Bulk packs often are, but specials on smaller sizes regularly flip that. It's worth checking, especially for things like coffee, cereal and washing powder.
Can I compare grams with millilitres?
Not directly – weight and volume aren't the same thing. The calculator ranks items by weight and by volume separately, and anything priced per item gets its own group.
Does cheapest per unit mean best value?
Only if you'll use it all. A huge pack that goes stale or off before you finish it can end up costing more.