Unit Price Comparison Calculator

Unit price comparison calculates the cost per standardized unit (per ounce, per gram, per liter, per sheet, per count) to determine which of two products is the genuine best value, regardless of package size, brand, or promotional packaging.

Core formula: Unit Price = Total Price ÷ Total Quantity Savings % = (Higher Unit Price − Lower Unit Price) ÷ Higher Unit Price × 100

What each variable means:

• Total Price: the shelf price or sale price of the item as packaged.
• Total Quantity: the amount of product inside: in ounces, grams, liters, sheets, count, etc. Always compare the same unit type.
• Unit Price: the cost per single unit of measurement. Lower unit price = better value per unit (though quality differences also matter).
• Standardized comparison: the only fair comparison. A 32 oz bottle at $4.99 vs. a 48 oz bottle at $6.99 cannot be compared by total price alone.

Common unit price comparisons:

Worked example 1, peanut butter: Brand A: 18 oz jar at $3.99 Brand B: 28 oz jar at $5.49

Unit price A = $3.99 ÷ 18 = $0.2217/oz Unit price B = $5.49 ÷ 28 = $0.1961/oz

Brand B saves: (0.2217 − 0.1961) ÷ 0.2217 × 100 = 11.5% cheaper per ounce

Work that from the rounded figures instead and you get 11.7%. It is a small gap, and it is the reason this calculator carries four decimal places on the unit price rather than two. Round early and the comparison drifts.

Worked example 2, toilet paper: Pack A: 12 double rolls (200 sheets each) at $8.99 Pack B: 6 mega rolls (500 sheets each) at $11.49

Total sheets A: 12 × 200 = 2,400 sheets → $8.99 ÷ 2,400 = $0.00375/sheet Total sheets B: 6 × 500 = 3,000 sheets → $11.49 ÷ 3,000 = $0.00383/sheet

Pack A wins on both counts: it costs less at the till and less per sheet. That is the case worth watching for, because the mega-roll pack looks like the bulk buy and the “buying bigger is cheaper” instinct is doing no work at all here. Note also that neither pack tells you its sheet count on the front. It is on the back, in small print, and it is the only number that matters.

Smart shopping rule: Always divide price by quantity. Never trust “value size” or “bulk” labeling without checking the math.