Unit Price Comparator

Compare product prices per unit ($/oz, $/ml, $/count) with visual comparison bars. Great for grocery shopping.

How to Use Unit Price Comparator

1

Enter first item

Type the price and quantity or weight of the first product.
2

Enter second item

Type the price and quantity or weight of the second product.
3

See the winner

View which item offers the better unit price value.

Tested tool guide Tested browser tools Checked August 16, 2026

What Unit Price Comparator does, with a checked example

A shelf price tells you what a package costs, not what the product costs. This tool divides each product's price by its package size - ounces, milliliters, or item count - and lines the results up as bars, so the shortest bar is the best value. Enter the products you are weighing up in the aisle and it normalizes them onto one per-unit scale, entirely in the browser, so it works with no connection. The thing shoppers most often get wrong: the biggest box is not automatically the best deal, and the small trial-size package is frequently the priciest per unit of all.

Worked example

A concrete input and expected output from the current implementation.

Input

Flakes, 12 oz, $3.00
Flakes Family, 24 oz, $4.56
Flakes Snack, 8 oz, $2.40

Expected output

Flakes: $0.25/oz
Flakes Family: $0.19/oz
Flakes Snack: $0.30/oz
Bars, shortest = best value: Flakes Family (24 oz) at $0.19/oz beats the 12 oz box at $0.25/oz; the $2.40 snack box is the most expensive per ounce despite the lowest shelf price.

Unit price is price divided by package size: $4.56 divided by 24 oz is $0.19, $3.00 divided by 12 oz is $0.25, and $2.40 divided by 8 oz is $0.30. The cheapest box on the shelf is the worst value per ounce - the pattern the tool exists to expose.

How the result is produced

Unit price arithmetic

For each product the tool divides the price you entered by the package size you entered: $4.56 divided by 24 oz gives $0.19 per ounce, and $2.40 divided by 8 oz gives $0.30 per ounce. The unit you choose - ounces, pounds, milliliters, liters, or a plain item count - becomes the denominator, so the result reads as price per that unit no matter how large the package is.

Comparison bars

Every product gets one bar, and each bar is scaled to that product's unit price, so the shortest bar is the best value. Adding another product, correcting a shelf price, or switching the unit recomputes the rates and the bars re-rank around the new numbers. The point of the visual is to remove mental arithmetic: the cheapest per-unit buy is the short bar, not the low shelf price.

Good uses

Standing in the cereal or pasta aisle, comparing the 12 oz, 24 oz, and 8 oz boxes of one brand to see which size is genuinely the better buy.
Pitting a store brand against a name brand when the packages are different sizes and the per-unit math is not obvious at a glance.
Checking multi-packs against singles - 12 rolls of paper towels versus 4-roll packs, or batteries by price per battery - to decide whether the bulk price is real.

Limits and checks

Mixed units are not comparable. Enter one product in ounces and the next in milliliters, and the bars no longer measure the same thing; weight, volume, and count are different scales. Enter every product in the same unit, converting package sizes by hand first, or the comparison is meaningless.
The output is only as good as the price typed in. Sale tags, coupons, and buy-one-get-one offers change the effective price, and a unit price computed from the regular sticker will not reflect the current deal. Retype the actual price you will pay at the register.
Per-weight comparisons break down for foods that change weight, like rice, dried beans, or frozen produce: the price per ounce of the dry or frozen product says nothing about the cost per cooked serving. For those, compare what you actually serve, or accept that the tool compares raw weights only.

Common questions

Can I compare a 32 fl oz bottle with a 1 L bottle?

Only if both quantities are entered in the same unit. A 1 L bottle holds about 33.8 US fluid ounces, so enter the liter bottle as 33.8 oz (or enter both in milliliters) before comparing it against a 32 fl oz bottle. With mixed units the bars measure different things, and the comparison will mislead you.

Why does the small package often cost more per unit than the big one?

Often by design: manufacturers price small and trial-size packages at a premium because convenience carries a markup, and per-unit pricing is what exposes it. The reverse happens too - a jumbo value pack is sometimes pricier per unit than the regular size - which is precisely the case this comparison exists to settle.

References and verification

The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.