TabSalary calculator guide
Compare grocery prices on equal terms
Shelf prices hide quantity differences. Unit pricing divides each product's price by its size so two packages can be compared on the same basis. It is especially useful for store brands, bulk packs, concentrates, and products sold in different counts.
Independently built and maintained · Published July 23, 2026 · Last reviewed August 23, 2026
Grocery packaging is engineered to be hard to compare. Brands shrink contents while keeping the box the same size, retailers stock the same product in three different counts, and a bigger package is not reliably cheaper per ounce despite looking like it should be. The shelf tag in most stores does show a unit price — but it rarely survives a comparison against an item sold by a different measure or sitting on a different shelf.
This calculator normalizes any two packages into one comparable number. Compatible units convert automatically — pounds to ounces, grams to kilograms, milliliters to liters — so a 500-gram import can compete fairly against a 1-pound domestic bag. The result reframes every choice as what you actually pay per unit of food rather than per trip to the register.
How the calculation works
Unit price = package price ÷ package size
- Choose two products measured by compatible mass, volume, or count units; compatible units convert automatically.
- Enter the price and total package size shown on each label.
- Compare the calculated cost per unit; the lower number is the cheaper quantity-adjusted option.
- Multiply the unit-price difference by your expected usage to estimate practical savings.
Worked example
A 16-ounce package at $3.99 costs about $0.249 per ounce. A 24-ounce package at $5.49 costs about $0.229 per ounce. The larger package is cheaper per ounce, but it is only the better purchase if you will use it before spoilage and can afford the higher checkout price.
What this estimate does not include
- Compatible units convert automatically, but mass, volume, and count cannot be compared with one another.
- Quality, nutrition, waste, storage space, coupons, loyalty rewards, and taxes can change the better choice.
- A bulk package is not a saving if part of it expires or causes you to consume more than intended.
Use the result as a planning estimate, not as personalized financial, tax, legal, or investment advice.
Source ledger
Primary references- National Institute of Standards and Technology Handbook 130: uniform unit-pricing regulation and package-labeling rules adopted by U.S. weights-and-measures jurisdictions.
- TabSalary formula review: prices are normalized only within compatible measurement dimensions.
Rates and rules are checked against the primary source before publication and re-checked whenever the source changes. External links open in a new tab; calculator inputs never leave your browser.