Mathematician Reveals How Supermarkets Are Conning The F*ck Out Of Us

geoff Robinson PhotographyGeoff Robinson Photography

Supermarkets, don’t trust the bastards.

Now one mathematician has helped expose the ways in which they try and rip us off, with confusing multi-buys and ‘buy one get one free’ offers.

Professor Bernhard von Stengel from the London School of Economics explained what supermarkets really mean when they say 100 per cent extra free. Rather than getting the whole product for free, you are actually getting two products for the price of one, so it works out as a 50 per cent reduction. Not bad, but not as good as was advertised.

1The Mirror

And when it comes to unit prices Von Stengel found they were finding ways to confuse shoppers, with some supermarkets pricing apples, for example, per fruit, rather than per kilogram, making comparison hard.

Sometimes they switch from ‘per gram’ to ‘per ml’ or ‘per tablet’ and even ‘per bag’ as well, making comparisons for some products nearly impossible, The Mirror reports.


But perhaps the cheekiest thing he found was a pack of tomatoes with a large British flag on the corner to highlight they were locally sourced, which is great, except the flag covered up the fact that you were actually getting one less tomato than you’d expect.

Don’t worry though, Von Stengel has some advice for confused shoppers: “One important recommendation is to use basic arithmetic and benchmarks of unit costs to check whether bulk offers are really cheaper than smaller packs. That is often not the case.”

Essentially, be aware of multi-buys and larger packs, always use the unit prices to calculate whether they actually are a better deal than smaller packs of the same products.