Unit Price Comparison Calculator
Formula
Unit Price = Total Price ÷ Size/Weight
Unit price tells you the cost per unit of measurement (per ounce, per gram, per liter). The lower unit price is the better deal, regardless of total package price. Buying in bulk isn't always cheaper — always check the unit price.
How to use
- Enter Price A and Size A for the first product.
- Enter Price B and Size B for the second product.
- Compare the two unit prices and read the savings percentage.
Example
Comparing $5.99 for 16 oz ($0.374/oz) against $8.99 for 32 oz ($0.281/oz), Product B is the better deal, saving about 24.9% per ounce.
Frequently Asked Questions
Is bigger always cheaper per unit?
Not always. Sometimes smaller sizes are on sale or the larger size has a higher per-unit cost. Always compare unit prices rather than assuming bulk is better.
What units should I use?
Use the same units for both products. Ounces (oz), grams (g), liters (L), or count — as long as both sides use the same measurement.
Does this work for non-food items?
Yes. Compare paper towels (price per sheet), laundry detergent (price per load), or any product where size varies between options.
What if the two products are sold in different units, like ounces and grams?
Convert one product so both use the same unit before comparing, since unit price only makes sense when the denominators match. For example, change grams to ounces by dividing by 28.35, then compute price per ounce for both. Skipping this step makes the larger-numbered package look cheaper per unit even when it isn't.
Should I always buy the option with the lowest unit price?
Not necessarily, because the cheapest per-unit deal only saves money if you actually use the product before it expires or spoils. Buying a giant container of a perishable item you rarely use can cost more in waste than the higher unit price of a smaller size. Factor in storage space, expiration dates, and how quickly you go through the item alongside the unit price.