How to use the unit price calculator
- For each product, enter the price, the quantity in the package and its unit.
- Use Add option to compare up to six products, or Remove to drop one.
- Press Compare. The result names the cheapest option, says how much cheaper it is per unit than the next best one and lists the price per unit of every option. The Details card shows a full breakdown.
Units of the same kind are converted for you, so you can compare a 12 oz box with a 500 g box. Weight, volume and count cannot be compared with each other, because there is no fair way to convert between them.
How unit price is calculated
Unit price = price ÷ quantity, after converting each quantity to a common unit. If your first option uses a US unit (oz, lb or fl oz), the calculator compares prices per ounce or per fluid ounce. If it uses a metric unit, it compares per kilogram or per liter. Items sold by count are compared per item.
The percentage shows how much less you pay per unit with the cheapest option: (next best unit price − cheapest unit price) ÷ next best unit price × 100.
Worked example
A 16 oz jar of peanut butter costs 3.49 and a 32 oz jar costs 5.99:
- Small jar: 3.49 ÷ 16 = 0.2181 per oz
- Large jar: 5.99 ÷ 32 = 0.1872 per oz
- The large jar is (0.2181 − 0.1872) ÷ 0.2181 ≈ 14.2% cheaper per ounce
Good to know
- Bigger is not always cheaper. Multipacks and sale prices on smaller sizes often beat the large package, which is why it pays to check.
- Fluid ounces here are US fluid ounces (about 29.57 ml). Weight ounces and fluid ounces are different units and cannot be mixed.
- Enter prices in a single currency. The calculator does not use currency symbols, so it works with any currency.
- A lower unit price only saves money if you will use the product before it spoils or expires.
- Shelf labels sometimes use different units for similar products, for example per 100 g on one item and per kg on another. Entering both here puts them on the same basis.