Price per unit is how much you pay for a single measurable unit of a product - one ounce, one pound, one item, one square inch. It is the universal comparison metric that strips away package size differences and lets you see which deal is genuinely cheaper. A 24 fl oz bottle at $2.99 vs. a 32 fl oz bottle at $3.89 - you can't compare just by price. Price per ounce reveals the truth: $0.125/oz vs. $0.122/oz. The bigger bottle wins.

Price per unit = Total price / Quantity. If a 64 oz bottle costs $5.12, the price per ounce is $5.12 / 64 = $0.08 per ounce. For pounds: $4.50 for 3 lbs = $1.50/lb. For items: $12 for a pack of 50 = $0.24 per item. This formula is the same regardless of unit type - it's just division.

Divide the product's total price by its weight in ounces. A 28 oz jar of peanut butter priced at $4.49: $4.49 / 28 = $0.160 per ounce. Compare this to a 40 oz jar at $5.99: $5.99 / 40 = $0.150 per ounce. The larger jar is 6.3% cheaper per ounce - worth it if you'll use it before it expires.

Divide the total price by the net weight in pounds. If ground beef is $9.47 for a 2.3 lb package, the price per pound is $9.47 / 2.3 = $4.12/lb. For bulk produce, if 5 lbs of apples costs $6.25, that's $6.25 / 5 = $1.25/lb. Knowing price per pound lets you compare bulk deals accurately across any package size.

Usually, but not always. Warehouse clubs and bulk stores often offer lower per-unit prices, but retailers sometimes price smaller packages at parity or even cheaper during promotions. Perishable items may not offer real savings if you can't use the full quantity before it expires. Always compare price per unit, not just the sticker price or the size of the packaging.