How to use this calculator
- Enter the old price and package size.
- Enter the new price and package size.
- Choose one unit for both packages and compare the unit-price change.
Example: Same price, smaller package
A 16 oz package at $4.99 costs about $0.3119 per ounce. If the package shrinks to 14 oz while the price stays at $4.99, the new unit price is about $0.3564 per ounce.
That is an effective price increase of about 14.29%. At the new unit price, the old 16 oz quantity would cost about $5.70.
What shrinkflation means in this calculator
Shrinkflation commonly describes a product becoming smaller while its sticker price stays the same or changes only a little. This calculator measures the unit-price change, whether it comes from a smaller package, a higher price, or both.
The formula is (new unit price ÷ old unit price − 1) × 100.
Calculations use the entered prices and amounts before rounding the display. For example, $4.00 for 16 oz changing to $4.40 for 14 oz raises the unit price by about 25.71%. See separate examples for price changes, size changes, and both together.
Frequently asked questions
Can I compare different units?
Convert both package sizes to the same unit first. For example, convert pounds to ounces or liters to fluid ounces before entering the values.
Does this account for quality changes?
No. The calculation only compares price and quantity. Changes to ingredients, quality, packaging, or convenience are not included.
Can this tell me why a package changed?
No. It measures the change in unit price, not a manufacturer's intent. Use it as a shopping comparison, not as a claim about how a product is marketed.