Comparing prices
Unit Prices Explained: Is the Bigger Pack Really Cheaper?
The shelf price tells you what a package costs. The unit price tells you what the food costs. Here’s how to use it.
5 min read · Updated Nov 3, 2026
What a unit price is
A unit price is the price divided by the amount: per ounce, per pound, per count. It lets you compare a 16 oz jar with a 28 oz jar, or a dozen eggs with a pack of eighteen.
For example, a 16 oz jar at $4.00 is 25 cents an ounce. A 28 oz jar at $6.30 is 22.5 cents an ounce. The bigger jar costs more at the register and less per ounce.
Where to find it
Many stores print the unit price in small type on the shelf tag, often per ounce or per 100 count. Check that two tags use the same unit before comparing. One might be per ounce and the other per pound.
When bigger isn’t better
- It spoils first. Half a bag of spinach in the trash costs more than the small bag.
- A sale on the small size. Discounts can flip which size is cheaper per ounce.
- You don’t have room. Storage is a real cost.
Comparing across stores
Unit prices matter most between stores, where packages rarely match. A warehouse club pack and a supermarket pack of the same item can only be compared per ounce. Here’s a fair way to compare two stores.
How AisleSplit uses it
When you’ve bought different sizes of the same item, AisleSplit works out the price per ounce from your receipts and marks the better deal, so you don’t have to do the math at the shelf.
Try it in AisleSplit
One list sorted by store, receipts that type themselves, and the prices you actually paid.
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