How unit price works
Unit price is the cost of a single item, serving or measure, so you can compare packages fairly. The formula is unit price = total price ÷ quantity. A pack costing $5.99 for 12 items is 5.99 ÷ 12 = $0.50 per unit (more precisely $0.499). The lower the unit price, the better the value for that size. A sale price changes the comparison, so run it through the percent off calculator first.
How to use this calculator
Enter the price of the package and the quantity it contains — this can be count, weight or volume, as long as you compare like with like. The result is the price per unit, with an exact three-decimal figure below for close calls. Compare two products by running each and picking the smaller number, the same logic behind the fuel economy calculator for miles per gallon. Layered promotions are handled by the discount calculator.
Worked example
A 32 oz bottle at $4.80 is 4.80 ÷ 32 = $0.15 per oz; a 20 oz bottle at $3.40 is 3.40 ÷ 20 = $0.17 per oz, so the big bottle is the better buy. Bulk is not always cheaper, so checking the unit price catches the exceptions. For the checkout total with tax, use the sales tax calculator.
Two traps worth knowing. Shrinkflation keeps the package price steady while quietly cutting the contents, so last year's $4.80 bottle at 32 oz may now hold 28 oz — that is $0.171 per oz, a 14% rise with no visible price change. And a multibuy such as "3 for $10" is only a deal if $3.33 beats the single-unit shelf price.
Frequently asked questions
- How do I calculate price per unit?
- Divide the total price by the quantity. A $5.99 pack of 12 is 5.99 ÷ 12 = about $0.50 per unit.
- What is the unit price of $5.99 for 12?
- About $0.50 per unit, or $0.499 to be exact.
- How do I compare two package sizes?
- Calculate the unit price for each, then pick the lower one. Make sure both use the same unit, like per ounce or per item.
- Is the bigger package always cheaper per unit?
- Not always. Sales and promotions can make a smaller pack the better value, which is exactly what the unit price reveals.
- Can I compare products sold in different units?
- Only after converting them to a common unit first. A price per ounce cannot be set against a price per litre until one side is converted, and a count-based pack (12 rolls) cannot be compared with a weight-based one at all.