Utility Stack
Free comparison calculator
Compare package sizes, discounts, and quantities to see which item costs less per unit.
Best deal
Divide the product price by the total amount in the package. If a 16 ounce item costs $5.99, the unit price is $5.99 divided by 16, or about $0.37 per ounce.
For multipacks, multiply the package size by the quantity first. A two-pack of 16 ounce items has 32 total ounces, so the unit price should use the combined amount.
Larger packages are not always cheaper. Unit price comparison helps you account for package size, multipacks, and sale discounts before choosing the better deal.
Unit price is especially useful when brands use different package sizes, when one item is on sale, or when warehouse-size products look cheaper but may spoil before you use them.
Unit price is most useful when the shelf prices are close but the package sizes are different. The lower package price is not always the better value.
| Comparison | Calculation | Better value |
|---|---|---|
| 16 oz for $5.99 vs 24 oz for $8.49 | $0.37/oz vs $0.35/oz | 24 oz package |
| 12 count for $4.50 vs 18 count for $6.75 | $0.38 each vs $0.38 each | Tie before other factors |
| 32 oz at 10% off vs 24 oz at regular price | Apply discount first, then divide by ounces | Depends on final unit price |
Apply any discount first, then divide the discounted price by the total units. This calculator includes a discount field for each item so sale prices can be compared fairly.
If a coupon applies only to one brand or one package size, enter that discount only for that item. If the discount applies to the whole order, use the Discount Calculator first and then compare the final prices here.
Compare ounces to ounces, grams to grams, counts to counts, and servings to servings. If one package lists pounds and the other lists ounces, convert them first with the Unit Converter so the comparison is fair.
Be careful with liquid volume, weight, and serving size. A bottle may list fluid ounces, a bag may list net weight, and a nutrition label may use servings. Choose the unit that matches how you actually use the product.
Common mistakes include comparing package price instead of unit price, forgetting the quantity in a multipack, mixing weight and volume units, or buying a larger package that will expire before it is used. The cheapest unit price is best only if you can actually use the product.
Also check whether the cheaper unit price requires a membership, subscription, minimum order, or coupon that will not apply to every shopper. Real value depends on the final price you can actually get.
The lowest unit price may still be the wrong buy if the package is too large, storage is limited, quality differs, or the item expires before you finish it. For fresh food, medicine, batteries, ink, and specialty ingredients, waste can erase the savings.
Use the unit price as the starting point, then factor in shelf life, brand preference, return policy, and whether buying more today creates a real budget strain.