The real price rise hidden in a smaller package, the way BLS counts it.
Who this is for: Checking whether a smaller pack is a price increase.
Same product, before and after
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$
How it is worked out
1Unit price before$5.99 ÷ 64 oz = $0.0936
2Unit price now$5.99 ÷ 60 oz = $0.0998
3Real price change$0.0998 ÷ $0.0936 − 1 = +6.67%
Calculated in your browser — the numbers you enter are never sent to our servers.
Work out the real price change when a product shrinks: the price per ounce, gram, litre or sheet before and after, the change on the shelf tag and in the package size, and the price the old size would cost now.
Best for: Groceries and snacks, Household paper products, Comparing pack sizes, Teaching unit prices
Updated September 2026 · Estimates only, not financial advice.
BLS counts 64 oz to 60 oz at $5.99 as a 6.7% price rise
The Bureau of Labor Statistics measures prices per unit, not per package. Its own example is a tub of ice cream that falls from 64 to 60 ounces while the price stays at $5.99: the price per ounce goes from about $0.094 to $0.0998, and the CPI records a 6.7% increase.
real change = unit price (now) ÷ unit price (before) − 1
The same applies to items without a weight. When a toilet paper roll goes from 220 sheets to 200, BLS adjusts the data to show a 10% increase in the price per sheet.
Ice cream, BLS example
$5.99 ÷ 64 oz = $0.0936 an ounce
$5.99 ÷ 60 oz = $0.0998 an ounce
0.0998 ÷ 0.0936 − 1 = 6.7%
A bag that shrinks 10% and costs 4.7% more is 16.3% dearer
When the price rises and the pack shrinks at the same time, the two effects multiply. A 10-ounce bag of chips at $4.29 that becomes 9 ounces at $4.49 costs 4.7% more on the shelf, but the price per ounce rises from 42.9¢ to 49.9¢, a real increase of 16.3%.
1 + real = (1 + shelf change) ÷ (1 + size change)
The relation is exact: one plus the real change equals one plus the shelf change, divided by one plus the size change. A 10% smaller pack alone is an 11.1% price rise, because the same money now buys 0.9 of the product.
Shrinkflation is already inside the official inflation rate
Because BLS adjusts for size changes, a downsized product raises the CPI just as a higher price tag would. Food and beverage prices rose 2.6% in the year to August 2026, with any downsizing counted.
BLS has also published research indexes that leave size changes out, to measure how much downsizing adds. Downsizing is most common in household paper products, snacks, cereal and cleaning supplies; items sold by weight or volume at the counter, such as gasoline or steak, cannot shrink this way.
A 16 oz pack cut to 15 oz hides a 6.7% rise
To hide a price increase at an unchanged shelf price, a maker has to shrink the pack to the old size divided by one plus the increase. Hiding 6.7% takes a 16-ounce pack to 14.995 ounces, which rounds to the 15 ounces a label would show.
hidden size = old size ÷ (1 + rise)
Run it the other way to judge a pack you see on the shelf: enter the old and new sizes at the same price, and the calculator returns the rise the new label is carrying.
Comparing two sizes on the shelf works the same way
The same arithmetic answers the everyday question of which pack is better value. Enter the two packs as before and after; a negative result means the second pack is cheaper per unit, a positive one that it costs more for each ounce, gram or sheet.
Unit prices on shelf labels do this for you when they use the same unit for both packs. When they do not, convert first, for example 16 fluid ounces to 473 millilitres, and compare like with like.
Worked example
BLS’s example: ice cream from 64 oz to 60 oz, still $5.99.
Worked example
Before = $5.99 ÷ 64 oz = $0.0936/oz
After = $5.99 ÷ 60 oz = $0.0998/oz
Shelf change = 0%
Size change = −6.25%
Real price change = +6.7%
Limitations
Compares the same product; a change in ingredients or quality is not captured.
Unit prices assume the product is used fully either way.
Frequently Asked Questions
What is shrinkflation?
Selling less product for the same or a slightly higher price. BLS’s example is a candy bar going from 1.6 to 1.5 ounces at an unchanged price: the price per ounce rises even though the shelf price does not.
Does the CPI include shrinkflation?
Yes. BLS adjusts for changes in item size, so ice cream cut from 64 to 60 ounces at $5.99 enters the CPI as a 6.7% price increase per ounce.
How do I calculate the price per ounce?
Divide the price by the size: $5.99 for 60 ounces is $0.0998 an ounce. Compare that with the old pack’s price per ounce to see the real change.
Sources & References
Figures on this page are checked against primary, authoritative sources. Links open in a new tab.
Results are estimates based on the figures you enter and standard formulas. Rates, fees, taxes, and lender terms vary and change over time, so confirm important numbers with your lender or a qualified professional. This is educational information, not financial advice.
Shrinkflation: How to Spot a Price Rise Hidden in a Smaller Package
A smaller pack at the same price is a price rise, and the CPI counts it as one. How to measure it per ounce or per sheet, with the BLS worked examples.
Published a shrinkflation calculator: price per unit before and after, the real change against the shelf and size changes, and the size that hides a rise.
BLS's own examples (ice cream 64→60 oz at $5.99 = 6.7%; toilet paper 220→200 sheets = 10%) reproduced exactly.
Added an automated formula suite with the BLS examples as the outside authority.
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