How the unit price calculator works
Unit price is the cost of one unit of the product, so packages of different sizes can be compared fairly.
Saving = (Higher unit price − Lower unit price) ÷ Higher unit price
Both quantities must be in the same unit: ounces with ounces, grams with grams, or count with count. Convert first if needed (1 lb = 16 oz, 1 kg = 1,000 g, 1 L ≈ 33.8 fl oz). For products like paper towels where sheet sizes differ, use square feet instead of roll count.
Worked example
A 16 oz jar of peanut butter costs $4.99 and a 32 oz jar costs $8.49. The small jar is 4.99 ÷ 16 = $0.3119 per ounce and the large jar is 8.49 ÷ 32 = $0.2653 per ounce. The larger jar is 14.9% cheaper per ounce, so buying it saves about $1.49 compared with two small jars.
Frequently asked questions
How do I calculate price per ounce?
Divide the price by the number of ounces. $3.60 for 12 oz is $0.30 per ounce.
Can I compare a pack of items with a weight?
No. Compare like with like. If one is sold by count and one by weight, find the weight per item first.
Is the larger package always the better deal?
Often but not always. Promotions, store brands and multipacks can make smaller sizes cheaper per unit.
What about buy one get one free?
Enter the price you pay and the total quantity you receive, including the free item.
Updated October 2026. Results are estimates for education, not financial or medical advice. All math runs in your browser; nothing you type is sent anywhere.