Starting With the Same Unit
Unit price divides the product's price by its quantity. A $4.80 box containing 24 ounces costs 20 cents per ounce. A $7.20 box containing 40 ounces costs 18 cents per ounce. In this illustrative example, the larger box provides more cereal for each dollar.
Shelf labels often show this calculation beside the package price. The important detail is the unit being used: an ounce, a pound, a fluid ounce or a count. A price per pound and a price per ounce need converting before comparison; one pound equals 16 ounces.
The quantity printed on the package is useful for online shopping, too. Dividing the listed price by that quantity makes different sizes easier to compare. All prices in the examples here are made up to show the calculation.
A Coupon Can Change the Better Buy
In the cereal example, a $1 coupon on the smaller box lowers its price to $3.80. Dividing $3.80 by 24 ounces gives about 15.8 cents per ounce. That makes the smaller box cheaper per ounce than the larger box at 18 cents.
The calculation uses the price after the applicable discount. A coupon must cover the exact size and variety being compared; a similar-looking box may have a different offer.
Multipacks work the same way. Three 12-ounce bags contain 36 ounces altogether, so the pack price is divided by 36. The number of bags alone cannot settle a comparison with a single larger bag.
Related searches: Grocery Coupons · Laundry Detergent Deals · Diaper Deals
Comparing Everyday Household Products
For laundry detergent, a household can also compare the package's stated wash count. A $12 bottle rated for 60 loads works out to 20 cents per load. A $16 bottle rated for 100 loads comes to 16 cents. Those estimates depend on following the labeled dose; using more detergent changes the actual cost.
Diapers are straightforward when the brand, style and size match. An $18 pack with 72 diapers costs 25 cents each. A $22 pack with 100 costs 22 cents each. Different diaper sizes may have different counts inside very similar packaging.
Paper products need a closer look because roll sizes differ. Sheet count, sheet dimensions and ply help explain what is inside a pack. A smaller price per roll may simply reflect a smaller roll.
A lower unit price is most useful when the household can use the whole purchase. Storage space, freshness and the amount needed still matter when choosing a package.
Current household promotions appear in Walmart Deals and CVS Deals. More practical shopping guides are available in Frugal Living & Finance.