How to Use the Unit Price Comparison Calculator
Even when you're comparing the same type of product at the grocery store, different sizes, brands, and packaging make it hard to tell at a glance which one is actually cheaper. A bigger size looks like the obvious deal, but small promotional packs or limited-time offers often have a lower unit price than the family size. This calculator takes the price and size of 2-3 products and automatically calculates the price per gram or mL, then ranks them for you.
The math is simple: divide each product's price by its size to get the price per gram (or mL), and the lower that number, the cheaper you're paying for the same amount. For example, a 16 oz detergent priced at $5 and a 32 oz bottle priced at $9 work out to about $0.31 and $0.28 per ounce โ the larger bottle really is the better deal here. But plenty of large sizes turn out to have a higher unit price too, so it's always worth checking directly rather than assuming.
Some stores post unit prices on the shelf tag, but many online listings and smaller shops don't show them at all. Comparing items like detergent, shampoo, snacks, or bottled water with this tool can help you trim real dollars off your grocery bill.
Frequently Asked Questions
Divide a product's price by its size in grams or mL to get the price per gram or mL. The lower this number, the cheaper you're paying for the same amount, meaning better value.
Not always. Small promotional sizes or limited-time deals often have a lower unit price than the family size. You need to calculate and compare unit prices directly to know which product is truly cheaper.