# Unit Price Comparator

> Free unit price comparator. Enter two prices and pack sizes, pick a unit, and see which product is cheaper per 100g, per litre or per piece, plus your savings.

The bigger pack is not always the better deal. Enter both prices, both quantities and the unit, and this calculator shows each product's unit price side by side, names the cheaper one, and tells you the percentage you save.

*Interactive tool: enter your values at https://toollantern.win/unit-price-comparator/ and results update instantly in your browser.*

## The unit price formula

Unit price = price ÷ quantity × base. For grams and milliliters the base is 100, giving the price per 100 g or per 100 ml, the format printed on most supermarket shelf labels. For kilograms, liters, ounces and pieces the base is 1, giving the price per kilogram, per liter, per ounce or per piece.

## Worked example

Product A: **500 g at 3.50**. Product B: **750 g at 4.80**.

- A: 3.50 ÷ 500 × 100 = **0.70 per 100 g**.

- B: 4.80 ÷ 750 × 100 = **0.64 per 100 g**.

- **Product B is cheaper**. Savings = (0.70 − 0.64) ÷ 0.70 × 100 ≈ **8.6%**.

## Why per 100 g is the standard

In the EU, shops must show the price per kilogram or per liter for most groceries, and per 100 g has become the everyday shorthand on labels and receipts because the numbers stay easy to read. In the US the same idea appears as the unit price on shelf tags, usually per ounce or per pound. This calculator uses per 100 g and per 100 ml for metric weights and volumes, and per ounce, per liter or per piece where that is the natural unit.

## Bulk is not always cheaper

Stores know shoppers assume the family pack is the bargain, so the large size is sometimes priced higher per unit than the regular one. Unit pricing cuts through that. One caveat: only compare like with like. A lower unit price is a real saving only if you will use the extra quantity before it expires or goes stale.

## Frequently asked questions
### What is unit pricing?

Unit pricing expresses a product's price for a standard quantity, such as per 100 grams or per liter, so packs of different sizes can be compared directly. Many supermarkets already print it in small type on the shelf label.

### How do I compare packs of different sizes?

Enter each product's price and its pack quantity in the same unit, for example both in grams, then compare the unit prices the calculator shows. The lower unit price is the better deal per unit.

### Should I use grams or ounces?

Use whichever unit is printed on the pack, as long as both products use the same one. If one pack is in grams and the other in ounces, convert first: one ounce is 28.3495 grams. Comparing across unit families, like grams and liters, is not meaningful.

### Does this calculator account for quality?

No. Unit price only compares price per quantity. Brand, quality, freshness and whether you will finish the pack are separate judgments this calculator cannot make.

### Why per 100 g instead of per gram?

Per-gram prices are tiny decimals that are hard to compare at a glance. Per 100 g gives readable numbers and matches the convention used on most price labels.

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Interactive version: https://toollantern.win/unit-price-comparator/