Unit Price Comparison Calculator
Comparing products sold in different sizes or pack counts can be confusing at the grocery store. Unit price cuts through the confusion by expressing every option as a cost per single unit of measure, whether that is per ounce, per gram, per count, or per liter. This calculator lets you compare up to three products side by side. Enter the price and quantity for each, and it instantly shows the unit price for each and highlights the best value. Use the same units across all three items for a fair comparison.
Item 1
Item 2
Item 3 (optional)
Unit price formula
Unit price = Price / Quantity
Use the same unit of measure for all quantities being compared. For example, if comparing two cereal boxes, both quantities should be in ounces. The item with the lowest unit price is the best value per unit.
Smart shopping with unit price
- Always check the shelf label: many grocery stores display unit price on the price tag below the product.
- For perishables like produce or dairy, factor in how much you will actually use before it spoils.
- Store brands and private labels often have lower unit prices than name brands for the same product.
- Buying in bulk is not always cheaper; compare unit prices across all sizes before assuming.
Unit price comparison: frequently asked questions
What is unit price?
Unit price is the cost per single unit of measure, such as per ounce, per liter, or per item. It lets you compare products sold in different sizes or pack counts on an equal basis. The lower the unit price, the better the value.
How do I use unit price to compare different sizes?
Divide the total price by the quantity for each option. For example, a 16-oz bottle for $2.40 costs $0.15 per oz, while a 24-oz bottle for $3.12 costs $0.13 per oz. The larger bottle is better value.
Does bulk always mean better value?
Not always. Larger packs usually have a lower unit price, but only if you can use the product before it expires or spoils. Factor in waste when comparing perishables.
What units should I use?
Use whatever unit is printed on the label: ounces, grams, liters, count, etc. The key is to use the same unit across all items you are comparing. Do not compare oz to grams without converting first.
Are unit prices required on grocery store shelves?
Federal law does not mandate shelf unit pricing, but many states have their own unit pricing laws. The FTC has issued guidance on the practice. Many major retailers display unit prices voluntarily.
Official sources
- Federal Trade Commission: ftc.gov consumer resources.
- U.S. Bureau of Labor Statistics, Consumer Price Index: bls.gov/cpi.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.