Unit Price Calculator

What is a unit price calculator?

A unit price calculator works out how much you pay for a single unit of a product — per item, per ounce, per litre, per kilogram, or any other unit — by dividing the total price you pay by the quantity you get. The unit price strips away package size so you can compare two products on an equal footing and pick the one that genuinely costs less.

Supermarkets call this the “price per unit,” and it is the number that lets you see past tricks like a larger box that looks cheaper but actually costs more per ounce. Whenever a bigger pack, a multipack, or a bulk deal is on the shelf next to a single item, the unit price is the figure that tells you which is the better buy.

How does the calculator work?

The calculator relates three quantities — the total price, the quantity, and the unit price — and solves for whichever one you leave blank. Choose what to calculate, fill in the other two values, and the answer appears.

The core relationship is:

$\text{unit price} = \frac{\text{total price}}{\text{quantity}}$

Rearranging the same equation lets you solve for the other two values:

$\text{total price} = \text{unit price} \times \text{quantity}$

$\text{quantity} = \frac{\text{total price}}{\text{unit price}}$

Worked examples

Find the unit price. A pack of 4 items costs $10. The price per item is:

$\frac{10}{4} = 2.50$

So each item costs $2.50.

Compare two packages. A 3-pack costs $15. Its unit price is:

$\frac{15}{3} = 5.00$

At $5.00 per item, the 3-pack is more expensive per unit than the $2.50 pack above, so the first deal is the better value.

Find the total price. If a single item costs $2.50 and you buy 4 of them, the total is:

$2.50 \times 4 = 10.00$

Find the quantity. If you spend $10 and each item costs $2.50, you receive:

$\frac{10}{2.50} = 4$

Practical notes

• Always compare unit prices using the same unit. Convert pounds to ounces, or litres to millilitres, before comparing — otherwise the comparison is meaningless.
• A lower unit price is not always the right choice: factor in whether you will actually use a larger quantity before it expires, and whether you have room to store it.
• Many price tags already show a unit price in small print. This calculator is handy when the store does not, when the units differ between products, or when you want to plan a budget around a target quantity.