Your favourite pack costs exactly what it did last year, but it feels lighter. That feeling has a name, shrinkflation, and it hides a price rise that is always bigger than the size cut printed on the pack. Here is the simple math to work out what you are really paying.
What shrinkflation actually is
Shrinkflation, also called package downsizing, is when a product gets smaller in size or quantity while its price stays the same. The word mixes “shrink” and “inflation”, and economists describe it as a rise in the price per unit of weight or volume, even though the price of one pack never moves.
Brands do it because shoppers react much more strongly to a higher price tag than to a slightly smaller pack. As economist Barak Orbach puts it, “In competitive markets, however, direct price increases are risky. Under such conditions, businesses often choose to raise prices indirectly through downsizing.”
The common mistake: a 15% cut is not a 15% rise
Most people assume that if a pack loses 15% of its contents, they are paying 15% more. They are not. You are now dividing the same price by a smaller quantity, so the price per gram rises faster than the pack shrinks.
The formula is short: real price rise (%) = (old size ÷ new size − 1) × 100. In plain words, divide the old quantity by the new one, take away 1, and turn the result into a percentage.
A real example: Tide detergent in India
In 2008, Procter and Gamble cut its Tide detergent pack in India from 1 kg to 850 g while keeping the same price. That is a 15% smaller pack.
- Old size ÷ new size: 1,000 ÷ 850 = 1.176
- Minus 1: 0.176
- As a percentage: a 17.6% price rise per kilo, not 15%
To see it in rupees, say the pack cost ₹200 (an illustrative figure). Before, you paid ₹200 per kg. After, you paid ₹200 for 850 g, which works out to ₹200 ÷ 0.85 = about ₹235 per kg. Same sticker, ₹35 more per kilo.
The gap grows as the cut gets bigger:
- Orbit chewing gum (around 2012): 6 pieces became 5 at the same ₹5. That is a 16.7% cut, but the price per piece went from about ₹0.83 to ₹1.00, a 20% rise.
- Idli (2013, reported by the Bangalore Mirror): 100 g shrank to 75 g. At an unchanged price, that is a 25% cut and a 33.3% rise per gram.
- Toblerone went from 200 g to 170 g in 2010, then to 150 g in 2016. Two cuts of 15% and about 12% look like 27% in total, but per gram at a steady price the bar became 33.3% more expensive.
When the price goes up as well
Sometimes the pack shrinks and the price climbs too. In 2022, Unilever reduced Dove soap bars from 100 g to 90 g, and some retailers raised prices at the same time. To combine both changes, use: real price rise = (new price ÷ old price) × (old size ÷ new size) − 1.
Say the bar went from ₹50 to ₹55 (illustrative prices). That is 1.10 × 1.111 = 1.222, so a 22.2% rise per gram. Adding the two changes (10% + 10%) would give you 20%, which again underestimates what you pay.
Why you rarely notice it
Marketers rely on what psychologists call the just-noticeable difference: the smallest change a person can perceive is a roughly fixed proportion of the original amount. Keeping a size cut below that threshold means most shoppers simply do not spot it. Some changes also come in disguise, like the wider gaps between Toblerone triangles or an air gap between segments of a chocolate orange.
Mistakes to avoid when checking a pack
- Reading the size cut as the price rise. Always divide old by new, never subtract.
- Counting packs instead of contents. In 2022, a mega pack of toilet paper kept its 18 rolls but each roll dropped from 264 to 244 sheets, roughly a roll and a half less per pack.
- Ignoring quality. A related trick, skimpflation, keeps size and price but cuts quality, such as a mayonnaise recipe with less egg yolk. No formula catches that, only the ingredient list.
- Trusting the front of the pack. The net weight or volume on the label is the only number that matters. Compare it with your last purchase, or use the shelf’s price per kilo or litre.
The fastest defence is the unit price. If you want the full method for comparing packs of different sizes, see our guide on how to calculate unit price and never overpay at the grocery store.
