How to use the unit price calculator
Enter the price and quantity for each package using the same unit. The lower price per unit is the cheaper option on that basis.
Unit price formula
A lower unit price can be useful for comparison, but it does not automatically mean a larger package is the better purchase if some of it will be wasted or if quality differs.
Example: Luis compares two package sizes
Luis compares a 12-ounce package costing $6 with a 20-ounce package costing $9. Package A costs $0.50 per ounce; Package B costs $0.45 per ounce.
Package B costs five cents less per ounce. Use the same quantity unit for both packages, and consider whether the extra quantity will be used before it expires.
Use the same quantity unit for both packages
A $4 package containing 500 grams costs $0.008 per gram. A $7 package containing 1,000 grams costs $0.007 per gram, making the second cheaper per gram.
Convert kilograms to grams, or liters to milliliters, before comparing mixed package units. A lower unit price helps only if you will use the extra quantity.
Compare a bulk pack with a smaller pack
A 12-ounce pack costing $3 has a unit price of $0.25 per ounce. A 20-ounce pack costing $4 has a unit price of $0.20 per ounce, so its price per ounce is 20% lower.
Convert both quantities to the same unit before entering them. Include the same discounts, delivery charges or other costs in each price if those costs belong in your comparison. The lower unit price does not account for waste or product quality.
Assumptions and limitations
What the estimate assumes
Quantities must use the same unit for a valid comparison.
Unit Price Calculator FAQs
How do I calculate price per ounce?
Divide the package price by the number of ounces.
Can I compare different units?
Convert them to the same unit first. For example, convert pounds to ounces before comparing price per ounce.
Does a lower unit price always mean better value?
Not necessarily. Consider quality, how much you will actually use, storage, and expiration.
Can I use this for non-food items?
Yes. Any two prices can be compared when the quantities use the same unit.
Unit-cost comparison only. Product quality, waste, coupons, taxes, and other purchase factors are not included.