About the Shrinkflation Calculator
Shrinkflation is when a product quietly gets smaller — a 16 oz bag becomes 14 oz, a 12-roll pack loses sheets per roll — while the price stays the same or even rises. Because the shelf price looks unchanged, the increase is easy to miss. This shrinkflation calculator compares the old and new price and size, converts both to a price per unit, and shows the true percentage price increase.
Enter what the product used to cost and weigh (or hold, or count), what it costs and contains now, and how often you buy it. You get the old and new unit prices, the size cut, the price the old package would cost at today’s unit price, and how much extra you would spend in a year to keep buying the same amount of product.
Both sizes must be in the same unit — ounces, grams, millilitres, sheets or count. The calculator works for any product, from snacks and coffee to detergent and toilet paper, and is a handy way to compare a “new look, same great taste” package against the one you remember.
With the default inputs, the real price increase is 14.3%. Change any value above to recalculate instantly.
How to use the shrinkflation calculator
- 1Enter the old price and package size from an old receipt, photo or memory.
- 2Enter the current price and the new size printed on the label.
- 3Make sure both sizes use the same unit and pick it from the list.
- 4Enter roughly how many packages you buy a year.
- 5Read the real price increase and the yearly cost of the shrink.
Formula and method
The fair way to compare two package sizes is the price per unit — per ounce, gram, millilitre or sheet. The real price increase is the percentage change in that unit price, which captures both a higher shelf price and a smaller package. If the price stays the same while the size falls from S₁ to S₂, the increase is S₁ ÷ S₂ − 1, so a 12.5% size cut is a 14.3% price rise.
The yearly extra cost assumes you keep consuming the same amount of product as before (the old size times your yearly purchases) and pay the new unit price for it. “Old size at today’s unit price” shows what the original package would cost if it were still sold at the new per-unit rate.
- P₁, S₁
- Old price and old package size
- P₂, S₂
- New price and new package size
- U₁, U₂
- Old and new price per unit
Worked examples
Same $4.99 price, bag shrinks from 16 oz to 14 oz
At $4.99 the price per ounce rises from $0.3119 to $0.3564, a 14.3% increase even though the shelf price never moved. The old 16 oz bag would cost $5.70 at the new rate. Buying 26 bags’ worth (416 oz) a year costs about $18.53 more.
Price up and size down: $3.49 for 12 rolls to $3.79 for 10 rolls
The shelf price rose 8.6%, but each roll went from $0.2908 to $0.379 — a 30.3% real increase. To keep using 240 rolls a year you would spend about $21.16 more.
Ice cream tub from 1.5 L to 1.25 L at $5.99
A one-sixth size cut at the same price means each litre costs 20% more ($4.79 vs $3.99). The original 1.5 L tub would cost $7.19 today, and 12 tubs’ worth a year costs $14.38 more.
Frequently asked questions
What is shrinkflation?+
Shrinkflation is when manufacturers reduce the amount of product in a package — weight, volume or count — while keeping the price the same or raising it. It is a price increase measured per unit, even when the sticker price does not change.
How do I calculate the real price increase from a smaller package?+
Divide price by size for both the old and new package to get unit prices, then divide the new unit price by the old one and subtract 1. At an unchanged price, the increase is old size ÷ new size − 1, so 16 oz to 14 oz is a 14.3% increase.
Why is the price increase bigger than the size cut?+
Because the percentages use different bases. Losing 2 oz from 16 oz is a 12.5% cut, but you now spread the same price over 14 oz, so each ounce costs 16 ÷ 14 = 1.143 times as much, a 14.3% increase.
How can I spot shrinkflation in the store?+
Check the unit price on the shelf tag, which many stores show per ounce, pound or count, and compare it with the same product over time or with other brands. Watch for redesigned packaging, deeper bottom indents, more air in bags and fewer sheets per roll.
Is shrinkflation counted in official inflation figures?+
Statistical agencies such as the US Bureau of Labor Statistics adjust for package size changes when pricing items in the Consumer Price Index, so a smaller package at the same price is recorded as a price increase.