Guide · Prices

Spot shrinkflation with your receipts

Updated 5 November 2026 · 3 min read

The surest way to spot shrinkflation is the unit price per kilo or litre: if it rises while the shelf price stays the same, there is less inside. The proof is on your old receipts. Bonstructer compares them automatically and lists shrunk products under "Less inside" in Statistics.

What is shrinkflation?

The maker shrinks the contents while the price stays the same or drops less. 200 g becomes 175 g, 1.5 l becomes 1.25 l. The pack often looks the same and the price feels familiar, so it goes unnoticed. In effect it is a price rise: you pay more per kilo. In Germany it is called a Mogelpackung, and the consumer centre in Hamburg names a "Mogelpackung des Jahres" every year.

How do you spot it in the shop?

• Compare the unit price: for packaged goods, German shops must show the price per kilo or litre next to the total (§ 4 Price Indication Ordinance).
• Read the net quantity, not the pack size: more air, a thicker base or a taller rim are easy to miss.
• "New recipe" or "new design" is often when the quantity changes too.
• Count pieces: tabs, wipes and bars often lose a few per pack.

How do you prove it with receipts?

1. Keep receipts, ideally digital, since thermal paper fades.
2. Line up the same product from the same shop over time.
3. Work out the price per kilo or litre: price divided by quantity times 1000.
4. Compare: the same price for a smaller pack, or a clearly higher unit price, is your proof.

How does Bonstructer check this automatically?

Bonstructer reads every line of your receipts and keeps product, shop, price and pack size. The "Less inside" card in Statistics flags a product when:

• the pack in the same shop got 3 to 50 % smaller,
• you bought the old size at least twice before,
• the price stayed the same (± 2 %) or the price per kilo or litre rose by at least 5 %,
• and the last purchase is less than a year old.

The row shows before → now, for example "200 g → 175 g · same price €1.79" with "+14 %/kg" next to it. A tap opens each purchase with date and receipt. Multipacks and goods sold by weight don't count.