How to calculate unit price
Unit price tells you how much a product costs for one standard quantity. It is useful when two packages have different prices, sizes or numbers of items.
If a purchase contains several identical packages, first calculate the total quantity.
Unit price example
Suppose Product A costs $6.99 for 500 g and Product B costs $7.49 for 600 g.
Product A costs $13.98 per kilogram:
Product B costs about $12.48 per kilogram:
Product B has the lower unit price even though its total shelf price is higher.
Comparing different units
Products do not have to use the exact same displayed unit. The calculator converts compatible measurements before comparing their unit prices.
For example, a 500 g package can be compared with a 1 kg package because both measure mass. An 8 oz package can also be compared with one measured in pounds.
The same applies to compatible volume measurements such as milliliters, liters, US fluid ounces, cups, pints, quarts and gallons.
Mass conversions used
Mass comparisons are normalized internally to grams and displayed primarily as price per kilogram, with common alternatives including price per 100 g, ounce and pound.
Volume conversions used
Volume comparisons are normalized to milliliters and displayed primarily as price per liter.
Comparing multipacks
Multipacks can make price comparison confusing because the label may show the quantity of one package while the price applies to the entire bundle.
Enter the quantity contained in each package and the number of packages included in the listed price.
For example, if a bundle costs $12 and contains four bottles of 500 mL each, the total quantity is 2 liters.
Price per item
For products sold by count, choose Item / each. The calculator divides the total price by the total number of items.
This is useful for comparing products such as batteries, paper rolls, capsules, cleaning cloths, food portions or other multipacks.
Cheapest price vs. best value
A lower total price does not necessarily mean a lower unit price. A larger package can cost more overall while still provide more product for each unit of currency.
Unit-price comparison removes the package-size difference and allows the two products to be compared on an equivalent basis.
How the savings percentage is calculated
The calculator compares the difference between the two normalized unit prices with the higher unit price.
This describes how much lower the cheaper unit price is relative to the more expensive option.
When unit price is not enough
Unit price compares quantity and cost only. It does not measure differences in quality, ingredients, durability, features, concentration, warranty, waste or personal preference.
For concentrated products, the package with the lowest price per liter or kilogram may not always provide the lowest cost per use.
Related everyday calculators
To calculate percentage differences or percentage changes, use the Percentage Calculator.
For comparing numerical relationships, use the Ratio Calculator.
To find the arithmetic average of a set of values, use the Average Calculator.
Only compatible measurement types should be compared. Count, mass and volume describe different kinds of quantity and cannot be converted directly into one another without additional information such as density or product-specific data.
Frequently asked questions
What is the unit price formula?
Divide the total purchase price by the total quantity received.
Can I compare grams with kilograms?
Yes. Both are mass units, so the calculator converts them to a common basis before comparing prices.
Can I compare ounces with pounds?
Yes. Ounces and pounds are compatible mass units and can be normalized for unit-price comparison.
Can I compare liters with gallons?
Yes. The calculator supports liters and US gallons as compatible volume measurements.
Why can I not compare kilograms with liters?
Kilograms measure mass while liters measure volume. Converting between them requires the density of the particular product, so they are not directly interchangeable.
Using this calculator effectively
The Unit Price Calculator compares two products by total price and quantity so you can see which has the lower cost per standard unit. It supports counts, mass, volume and multipacks, and automatically normalizes compatible measurement units.
Common uses
- Comparing grocery or household products sold in different package sizes.
- Checking price per kilogram, liter, ounce, pound or individual item.
- Comparing multipacks where one listed price covers several packages.
Tips for a better estimate
- Enter the total price actually paid for all packages included in the comparison.
- Use the quantity contained in one package and enter the package count separately for multipacks.
- Compare only compatible quantities such as mass with mass, volume with volume or item counts with item counts.