THE SHORT ANSWER
Compare unit prices, not just the price tag
Divide each price by its package size, then calculate the percentage change. A package shrinking from 16 oz to 14 oz at the same price raises the unit price by about 14.29%.
Why a smaller package can hide a price increase
A product may stay at $4.99 while the package quietly changes from 16 oz to 14 oz. The sticker price looks unchanged, but you are receiving less for the same amount of money.
Unit price puts both packages on equal footing. It answers the practical question: how much does one ounce, one fluid ounce, or one item cost before and after the change?
Work through the 16 oz to 14 oz example
Scroll sideways to see the full table.
| Package | Price | Size | Price per oz |
|---|---|---|---|
| Before | $4.99 | 16 oz | About $0.3119 |
| After | $4.99 | 14 oz | About $0.3564 |
Divide $4.99 by 16 for the old unit price and by 14 for the new one. The package is 12.5% smaller, but the unit price rises by 14.29%. Those percentages differ because the price increase is measured from the lower, original unit price.
Shrinkflation formula
For the example above, the calculation is approximately ($0.3564 ÷ $0.3119 − 1) × 100 = 14.29%. Another useful way to explain the change is to price the old quantity at the new rate: 16 oz would now cost about $5.70.
Make the comparison fair
- Use the same unit. Convert both packages to ounces, fluid ounces, pounds, grams, milliliters, or count before comparing.
- Check multipacks carefully. Compare the total quantity in the entire package, not just the number of inner packs.
- Remember what the math leaves out. Ingredients, quality, packaging, and convenience may also change.
The unit-price result describes the size and price change. It does not determine why the manufacturer changed the product.