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Unit Price — Definition, Formula & Examples

Unit price is the cost of one single unit of an item, found by dividing the total price by the number of units. It lets you compare deals on products sold in different quantities.

The unit price of a commodity is the quotient obtained by dividing the total cost by the total number of units purchased, expressed in currency per unit. It is a specific application of a unit rate where the quantity in the denominator is measured in countable or measurable units of a product.

Key Formula

Unit Price=Total PriceNumber of Units\text{Unit Price} = \frac{\text{Total Price}}{\text{Number of Units}}
Where:
  • Total Price\text{Total Price} = The cost of the entire package or quantity purchased
  • Number of Units\text{Number of Units} = The count, weight, or volume of items in the package

Worked Example

Problem: A 12-pack of water bottles costs $4.20 and a 5-pack costs $2.00. Which is the better deal?
Find unit price of the 12-pack: Divide the total price by the number of bottles.
$4.2012=$0.35 per bottle\frac{\$4.20}{12} = \$0.35 \text{ per bottle}
Find unit price of the 5-pack: Divide the total price by the number of bottles.
$2.005=$0.40 per bottle\frac{\$2.00}{5} = \$0.40 \text{ per bottle}
Compare: The lower unit price is the better deal.
$0.35<$0.40\$0.35 < \$0.40
Answer: The 12-pack is the better deal at $0.35 per bottle compared to $0.40 per bottle.

Why It Matters

Grocery stores are required to display unit prices on shelf labels, making this one of the most frequently used math skills in everyday life. Understanding unit price also builds the foundation for rates and proportional reasoning problems you will encounter throughout algebra and science courses.

Common Mistakes

Mistake: Dividing the number of units by the price instead of the price by the number of units.
Correction: Always put the price in the numerator and the quantity in the denominator. The result should be in dollars (or cents) per unit, not units per dollar.