Unit Price Calculator: Which Size Is the Better Deal?
Compare two pack sizes by price per ounce, gram or item, and see which is cheaper and by how much.
Inputs
- Working
- A: 4.49 ÷ 16 = 0.2806 per oz; B: 7.99 ÷ 32 = 0.2497 per oz
- Per 100 oz
- A 28.06 · B 24.97
- Saving on 16 oz at the cheaper rate
- 0.50
- Unit price A
- 0.2806
- Unit price B
- 0.2497
- The other way round
- Option A costs 12.4% more per oz
Use this calculator on your own site
Free embed
- Two lines of HTML, unlimited views
- Shows a small CalculateEveryday bar, with a credit link under the calculator
What each Unit Price input means
- Option A price
- What the first option costs on the shelf, after any multi-buy offer you would actually use.
- Option A quantity
- How much the first option contains — ounces, grams, rolls, pods — in the same unit as option B.
- Option B price
- The second option's price.
- Option B quantity
- The second option's quantity, in the same unit. Convert first if needed: 1 lb = 16 oz, 1 kg = 1,000 g.
- Unit both are measured in
- The unit's name, used only in the result's wording, such as oz, g, roll or sheet.
Unit Price formula
unit price = price ÷ quantity · % cheaper = (higher − lower) ÷ higher × 100
To compare packs of different sizes, divide each price by its quantity to get the price per ounce, gram, sheet or item, then compare those. Both quantities must be in the same unit — convert pounds to ounces (×16) or kilograms to grams (×1,000) first. The page shows each unit price, the price per 100 units (as many shelf tags do), how much cheaper the better option is in percent, and what that saves on the smaller quantity. Bigger is often but not always cheaper per unit, which is why it is worth checking.
Unit Price worked example
A 16 oz jar at $4.49 is 4.49 ÷ 16 = $0.28 an ounce; a 32 oz jar at $7.99 is $0.25 an ounce. The big jar is 11% cheaper per ounce — the small one costs 12.4% more — and about $0.50 is saved on 16 ounces, as long as you use it before it goes off.
More Unit Price examples
Paper towels: 12 rolls for $3.20 or 24 for $5.60. That is 0.2667 against 0.2333 a roll, so the result reads Option B, 12.5% cheaper per roll — the 12-pack costs 14.3% more per roll.
Where the Unit Price calculator can give the wrong answer
- The units must match. 1 lb is 16 oz and 1 kg is 1,000 g; a store tag may also mix price per ounce and per pound.
- Multi-buy offers change the price: enter what you would actually pay for each option.
- A cheaper unit price is only a saving if you use it all. Food that spoils or a product you will not finish costs more than it looks.
- Count-based items work too: price per roll, per diaper, per pod.
Spotted a mistake? Tell us
Unit Price FAQ
- Divide the price by the quantity. A {{$7.99}} 32 oz jar is 7.99 ÷ 32 = {{$0.25}} an ounce.
- Usually, not always. Sales on the smaller size, or a premium on the 'family size', can flip it — which is what the comparison is for.
- Convert one of them: a price per pound ÷ 16 is the price per ounce. {{$3.20}} a pound is {{$0.20}} an ounce.
- The unit price scaled to 100 units so small numbers are easier to compare. The page shows the same figure for both options.
- Each is measured against a different price. If one item is 0.25 and another 0.20, the cheaper one is 20% below the dearer (0.05 ÷ 0.25), while the dearer one is 25% above the cheaper (0.05 ÷ 0.20). The page shows both.