Price Per Unit Calculator
Compare prices by calculating cost per unit, ounce, gram, or item.
Find the best deal when shopping between different package sizes.
Price per unit lets you compare products of different sizes to find the best deal. When two products come in different quantities or package sizes, the sticker price alone does not tell you which is cheaper. You have to compare the cost per individual unit.
Formula:
Price per Unit = Total Price / Number of Units
Where:
- Total Price = the price shown on the shelf or tag for that package
- Number of Units = the quantity in the package (ounces, grams, count, liters, sheets, etc.)
The product with the lower price per unit is the better value, assuming equal quality.
Examples of “units” by product type:
| Product | Unit to Compare |
|---|---|
| Cereal, snacks, meat | Price per ounce or gram |
| Beverages | Price per liter or fluid ounce |
| Paper towels, toilet paper | Price per sheet or roll |
| Laundry detergent | Price per load |
| Eggs, batteries, multipacks | Price per item |
Practical Example: You are comparing two brands of olive oil. Option A: 16 oz bottle for $6.99, so $6.99 / 16 = $0.4369/oz Option B: 25 oz bottle for $9.49, so $9.49 / 25 = $0.3796/oz
Option B is 13.1% cheaper per ounce, a difference of $0.0573 an ounce. Over the 25 oz bottle that is $1.43 saved, which is real but not dramatic. That distinction matters: a percentage looks impressive on its own, and the dollar figure tells you whether it is worth carrying the bigger bottle home.
When to use this calculator: At the grocery store, the warehouse club, or online, whenever you are choosing between sizes of the same product. Both quantities have to be in the same unit. If one bottle is in millilitres and the other in fluid ounces, convert before you compare, or you will get a confident answer that is wrong by a factor of thirty.
Shopping tips:
- Bigger packages are not always cheaper per unit. Warehouse clubs are usually cheaper; the “family size” box at a regular supermarket often is not, and stores rely on you assuming otherwise.
- Store brands frequently beat name brands on unit price for what is, in a surprising number of categories, product from the same factory.
- Most US supermarkets print the unit price on the shelf tag in small type. It is legally required in about twenty states and voluntary elsewhere.
- Waste ruins the arithmetic. A 20% saving on produce where a third spoils is not a saving.
- Storage counts. So does the cash: buying six months of detergent is cheaper per load and worse for your bank balance this week.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.