Unit price comparator

How to use this application

Different pack sizes. One fair comparison.

A smaller price tag does not always mean better value. This unit price comparator converts each package to a common quantity, so you can compare two to six options without doing the conversions yourself. Use it for similar groceries, household supplies or multipacks.

Enter your options

1. Enter the full price of each pack, using the same currency for every option. Leave out currency symbols and thousands separators. Decimal points are supported.
2. Enter the quantity inside that pack and select its unit. For a multipack, enter the combined quantity: six 250 mL bottles contain 1,500 mL.
3. Choose Compare prices. Mass is shown per 100 g, volume per 100 mL, and count per item. The lowest unit price is highlighted. Equal prices are marked as tied.
4. Use Add option for more choices, or Clear all to start again. Changing an input clears old results so an outdated comparison is not mistaken for the current one.

A worked example

Choose Load example to compare a 250 g pack priced at 3 with a 0.5 kg pack priced at 5. The smaller pack costs 1.2 per 100 g. The larger pack costs 1 per 100 g, making its unit price about 16.7% lower than the smaller pack’s. This percentage compares the lowest unit price with each other option; it does not compare the total amount you would spend at checkout.

Compare the amount you actually need

Optionally enter a quantity needed and a compatible unit. The calculator rounds up to whole packs of each option separately, then shows the number of packs, total price, supplied quantity and leftover amount. These are alternative single-option purchases, such as choosing one brand or pack format. It does not search combinations of different options; a mixture could cost less. All listed packs are assumed to be available at their fixed entered price.

The fictional example also enters a 250 g need. One small pack costs 3 and supplies exactly 250 g; one large pack costs 5 and leaves 250 g. The large pack still has the lower unit price, but the small pack has the lower total for that single-option purchase. Clear the quantity needed to return to unit-price-only comparison. Neither ranking evaluates quality, useful life or whether different brands can be substituted.

Whole-pack mode accepts ordinary decimal notation with up to six decimal places, using exact decimal arithmetic for pack counts and totals. Scientific notation is not supported in this mode. Required amounts and pack quantities for counted items must be whole numbers. Prices and quantities remain positive and at most 1,000,000,000. Provided and leftover quantities are shown in grams, millilitres or items. Currency-specific cash rounding, tax, shipping, coupons, changing prices, limited stock and quantity discounts are not calculated.

Use Save comparison note to download the entered options, displayed results and assumptions as UTF-8 plain text. Editing, adding or removing an option clears the old note and results. Clear all resets the needed amount as well. Nothing is automatically saved; downloaded copies remain on your device and should be reviewed before use.

Compare like with like

Only compare products with compatible units. Grams and kilograms can be compared, as can millilitres and litres. An item count cannot be compared with a weight, and this tool does not convert mass to volume. For counted items, make sure one item has the same size in every option. A small roll and a large roll are not necessarily equivalent.

Price is only one part of value. Consider quality, ingredients, how much you will actually use, waste, available space and your total budget. A large pack can have a lower unit price while costing more upfront. This calculator does not evaluate product quality or recommend a purchase.

What the calculator includes—and its limits

Prices and quantities must be positive and no greater than 1,000,000,000. Zero-price promotions are not supported. Enter the final effective pack price yourself if a discount applies. The tool does not calculate tax, delivery fees, coupons, loyalty rewards, exchange rates or “buy one, get one” promotions. All options must use one currency; the result uses that same currency without assuming a symbol.

Unit-price calculations use JavaScript floating-point numbers. Results show up to six significant digits, and savings show one decimal place. Very close results are treated as a tie within a relative tolerance of one part in a billion. Treat tiny differences as approximate, particularly when package labels or prices have already been rounded.

Your entries stay in this page

The calculator runs in your browser. It does not send entries anywhere, use analytics, create an account, set cookies or write to browser storage. Values exist in the current page’s memory. Clear all removes them; reloading or leaving the page starts a fresh comparison. Browser features such as autofill, session restoration or extensions are outside this application’s control. There is no automatic comparison history or cross-device sync; a comparison note is saved only when you explicitly download it.

Once the page assets have loaded, calculations need no network connection. This MVP does not install an offline service worker, so opening or reloading the page still requires access to its files. JavaScript must be enabled to use the calculator; these instructions remain readable without it.