Unit price calculator

How to read your result

Each item shows its price for one unit of whatever you picked under Show price per, plus the total amount you get. The cheapest item is highlighted and marked Lowest; every other item says how much more it costs per unit, as a percentage. The line under the items names the better buy and how much less it costs than the runner-up.

Items measured in a different kind of unit than the one you are comparing by are left out of the ranking and marked as not comparable. A blank or invalid field shows what is missing instead of a guess.

How the calculator works

For each item, the calculator multiplies the size by the number of packs, converts that total into your comparison unit, and divides the price by it. Conversions use exact US definitions:

Weight, volume and count are never converted into each other. Everything runs in your browser; nothing you type is sent anywhere.

Worked example: a 12 oz bag or a 2 lb bag?

A 12-ounce bag of coffee costs $8.99 and a 2-pound bag costs $19.99. Two pounds is 32 ounces, so the big bag works out to $19.99 ÷ 32 = about 62 cents an ounce, against $8.99 ÷ 12 = about 75 cents an ounce for the small one. The 2-pound bag costs about 17% less per ounce, even though its sticker price is more than twice as high. Those are the numbers already loaded in the calculator above.

When the cheapest unit price is not the better buy

• Wet and dry pet food. Canned food is mostly water, so it almost always looks expensive per pound next to kibble. Compare dry cat food with dry and wet cat food with wet.
• Protein powder. Price per pound counts the whole powder, so a mass gainer can rank cheap while holding little protein. See how to compare protein per gram.
• Toilet paper and paper towels. Compare by sheet, not roll. PriceCrow ranks toilet paper per sheet and paper towels per sheet.
• Laundry detergent. Compare by load, which puts pods, liquid and powder on one scale: laundry detergent per load.
• Food that spoils. A bulk size is only cheaper if you finish it.

Skip the typing for Amazon

If you are shopping on Amazon, PriceCrow does this math across dozens of listings at once: search a product, pick a unit, and get every comparable listing ranked by unit price. Browse popular comparisons or the full A–Z list.

Questions

How do you calculate unit price?

Divide the price by the total quantity in the package. A $19.99 bag holding 2 pounds is $19.99 ÷ 32 ounces, or about 62 cents per ounce. When packages use different units, convert both to the same unit first; the calculator does that for you.

Is the bigger package always cheaper per unit?

Usually, but not always. A sale or coupon on a smaller size can make it cheaper per unit than the bulk size, which is why it is worth checking the unit price instead of assuming.

Can I compare fluid ounces with ounces?

No. Fluid ounces measure volume and ounces measure weight, and how much a fluid ounce weighs depends on what is in the bottle. The calculator only ranks items measured in the same kind of unit, and marks the rest as not comparable.

What does the Packs field do?

It multiplies the size. A listing for 6 bottles of 16.9 fluid ounces is size 16.9, unit fluid ounces, packs 6, so the calculator prices all 101.4 fluid ounces.

Why compare toilet paper or paper towels by sheet?

Roll sizes are not standard. Brands define mega, family and XL rolls as different numbers of regular rolls, so the price per roll can compare very different amounts of paper. The sheet count is printed on the package, which makes price per sheet the fair comparison.