Which size is the better deal?

Sizes ranked by unit price

How to calculate unit price

Divide the price by the amount in the package, in the same unit for every size you compare. The lowest result is the better deal, as long as you will use it all.

Worked example from today's ground coffee prices: a 27.5 oz pack costs $13.66 on Amazon, which is $13.66 ÷ 27.5 = $0.497 per oz. A 32 oz pack costs $15.40, or $0.481 per oz. The bigger pack saves 3% per ounce. Try it in the calculator

Shelf tags often show a unit price already, but stores do not always use the same unit on every tag (per ounce on one, per pound or per count on the next), so check before you compare.

Price per ounce vs price per pound

A pound is 16 ounces, so price per pound = price per ounce × 16, and price per ounce = price per pound ÷ 16. Convert both prices to the same unit before you compare.

Worked example from this week's Better Health Market ad: Raised Gluten-Free Pies Dutch Apple, Cran-Apple, Pumpkin, 22 oz for $19.99. That is $0.909 per ounce, or $14.54 per pound. If the deli or bulk bin sells the same thing loose for less than that per pound, the loose one is cheaper. Try it in the calculator

Metric sizes convert the same way: 1 ounce is 28.35 grams, 1 pound is 453.6 grams, and 1 fluid ounce is 29.57 milliliters. Ounces (weight) and fluid ounces (volume) are different units, so a jar sold by weight cannot be compared directly with a bottle sold by volume.

Bulk vs unit price

The bulk pack is only the better deal if its price per unit is lower and you use it all before it goes stale or expires. Big packs are usually, but not always, cheaper per unit.

Worked example from today's paper towels prices: the smallest pack, 12 rolls for $8.48 (Amazon), works out to $0.71 per roll. The biggest, 40 rolls for $22.86 (Amazon), is $0.57 per roll. Buying in bulk saves 19% per roll. Try it in the calculator

Roll and sheet counts differ by brand: a "mega" roll is not a standard size, so compare by sheet count or square feet when the package lists it.

BOGO unit price

Buy one, get one free halves the unit price, but only if you buy both. Buy one get one 50% off cuts it by a quarter, and buy two get one free by a third.

Worked example from this week's Buehler's Fresh Foods ad: Pepsi Products, 6 items for $7.99, buy 2 get 1 free. 3 cost $15.98 for 18 items, which is $0.888 per item instead of $1.332. Try it in the calculator

BOGO prices are sometimes set above the everyday price, so compare the deal's unit price with the regular price at another store before you stock up.

Multi-buy deals: 2 for $5

Divide the deal price by the number of items to get the price of one, then divide by the size. Many stores ring up a single item at the split price unless the ad says you must buy the full number; check the fine print.

Worked example from this week's Garden Fresh Marketplace ad: Our Family Shredded Cheese, 2 for $4.00. One costs $2.00; at 8 oz that is $0.250 per oz. Try it in the calculator

Unit prices we track

We rank hundreds of groceries and household staples by price per unit across Amazon and eBay every day on the price per unit pages, and compare this week's supermarket ads in grocery prices near you. To check a pack against the cheapest online, use which pack is cheaper; to total a whole list, the shopping list.

Examples use prices checked Nov 15, 2026: Amazon and eBay item-plus-shipping prices for the per-unit pages, and store weekly ads valid through Nov 15 for the grocery examples. Ad prices vary by region.

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