Unit Price Calculator
Compare price per unit across products — instantly see which size or brand is cheapest.
What is unit price and why does it matter?
Unit price is the cost per single unit of a product — per gram, per litre, per sheet, per ounce. It lets you compare products that come in different sizes or quantities on a level playing field. The 500g pack that costs £2.50 (£0.50/100g) is a better deal than the 300g pack at £1.70 (£0.57/100g) even though it has a higher sticker price. Most supermarkets are legally required to display unit prices, but comparing across stores or online is easier with a calculator.
Frequently asked questions
What units can I use?
Any unit — g, kg, ml, L, oz, lb, sheets, rolls, pieces. The unit label is just for your reference; the calculator divides price by quantity regardless of the label. Just make sure all three items use the same unit when comparing.
Does a lower unit price always mean better value?
Not always — unit price only measures monetary cost per unit of weight or volume. Factors like quality differences, shelf life, packaging waste, storage space, and whether you'll actually use all of a larger pack before it expires can all affect real-world value. The cheapest per unit isn't always the smartest buy.
Why do larger sizes usually have a lower unit price?
Economies of scale — packaging costs relatively less per unit of product, and logistics costs are lower per unit for bulk sizes. Manufacturers and retailers also use bulk discounts to encourage shoppers to buy more in a single transaction, increasing the average basket size.
