How to tell if a Black Friday discount is real (in 10 seconds)
On Black Friday almost everything comes with a huge percentage next to it. But "-50%" only means something if the old price really was the old price. The good news: checking it takes less time than reading the product page.
What the rules say
In the European Union, when a shop announces a price reduction, the "previous" price it shows must be the lowest price it charged in the previous 30 days. This stops the classic trick of raising the price in October to "cut" it in November. Other countries have their own rules, and marketplaces host thousands of sellers, so it pays to check yourself.
The 10-second calculation
You need three numbers: the crossed-out price, the current price and, if you can find it, the lowest price in the last month (price-tracking browser extensions show it).
- Advertised discount = (crossed-out − now) ÷ crossed-out.
- Real discount = (lowest last month − now) ÷ lowest last month.
Example: headphones crossed out at 100 and now at 70 advertise 30% off. If two weeks ago they cost 80, the real discount is 10 on 80: 12.5%. If ten days ago they were 65, today is no discount at all.
Skip the maths with our Black Friday discount checker: type the three prices and it tells you whether the deal is real, inflated or fake.
Signs of an inflated deal
- The product has been "on sale" all year.
- The percentage is huge but the final price matches other shops.
- There is a countdown but no information about the previous price.
- The "recommended price" is a figure nobody has ever paid.
The most important question
A real discount on something you were not going to buy is still spending. Before looking at the discount, look at your list: if it was not there, wait 48 hours. If it still feels necessary, buy it with a clear head.
And decide before Friday how much you will spend in total. With a number in mind, percentages are far less impressive.
