Is the larger package actually cheaper?
A shelf price answers how much you pay at checkout. A unit price answers how much you pay for an equal quantity. Compare both before buying more than you need.
- Choose two equivalent products: check quality, concentration and usable portions.
- Enter the full price and total net quantity for each offer. Four 6 oz containers contain 24 oz in total.
- Select each quantity’s unit. The tool converts compatible weights or volumes to the same basis.
- Compare the unit prices, then consider your cash budget, storage and how much you will actually use.
How the comparison works
For weight, prices are shown per 100 g. For volume, they are per 100 mL. Count comparisons use price per equivalent item. Unit price equals total price divided by total quantity after conversion. The percentage gap is the difference between the higher and lower unit prices divided by the higher one.
For example, $4.80 for 16 oz is $0.30 per oz. A $6.60 package containing 24 oz is $0.275 per oz, about 8.3% lower by unit price. You still spend $1.80 more at checkout. If some of the larger pack goes unused, it may be the worse purchase for your household.
What to check on the label
Use net contents rather than a shipping weight. Use drained weight consistently when that is the relevant edible portion. Count units only make sense for comparable items: a large egg and a tiny egg are not equivalent just because both count as one. Concentrated and ready-to-use products need a comparable prepared yield before comparing prices.
Weight and volume are different
US fluid ounces measure volume; ordinary ounces here measure weight. The calculator deliberately refuses to compare weight with volume or counts. It does not estimate food density or convert Imperial fluid ounces. Standard fixed conversions include 1 lb = 453.59237 g and 1 US fl oz = 29.5735295625 mL.
Keep a price book for regular purchases
For items you buy often, record the item, store, date, net quantity and unit price. Recheck old observations before shopping; a low price last month is not a live offer today. Include known taxes or unavoidable fees consistently. Coupons, memberships, travel costs and waste are not calculated automatically.
The $9 Grocery Savings Toolkit adds a 50-row price book, pantry inventory, shopping budget and meals-with-leftovers plan. This free comparison works without buying the workbook.
Keep planning
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Method reviewed November 3, 2026. Educational arithmetic; no individualized financial recommendations.