Unit price arithmetic
For each product the tool divides the price you entered by the package size you entered: $4.56 divided by 24 oz gives $0.19 per ounce, and $2.40 divided by 8 oz gives $0.30 per ounce. The unit you choose - ounces, pounds, milliliters, liters, or a plain item count - becomes the denominator, so the result reads as price per that unit no matter how large the package is.