Black Friday 2026 lands on Friday 27 November, but UK retailers have been starting their "Black Friday" sales earlier every year — some now run for most of November. More sale days means more banners, more countdown timers and more chances to buy something that isn't really a bargain. Here's a simple five-step check to run on any deal before you hit pay.
1. Work out the real percentage off
"Was £75, now £55" feels like a third off. It's actually 26.7% off (£20 ÷ £75). Retailers know that big round numbers in the "was" price make the saving feel larger than it is.
Quick formula: (was − now) ÷ was × 100. Or drop both prices into a discount calculator and get the answer in a second.
2. Check the "was" price was ever real
A discount is only meaningful if the item actually sold at the higher price. Before Black Friday, note the price of anything you're planning to buy. If the "was" price on the day is higher than what you saw in October, the saving is partly invented. Price history tools, or simply bookmarking a product page a few weeks ahead, are the easiest checks.
3. Stack codes — but do the maths properly
Black Friday is when "extra 20% off sale items" codes appear. Stacked discounts multiply: 30% off then an extra 20% off is 44% off, not 50%. On a £150 coat that's £84, not £75 — a £9 difference from what most people assume.
A stacked discount calculator shows the real final price when a sale and a voucher code are combined.
4. Compare per unit, not per pack
Black Friday multipacks and bundles often look cheaper because they're bigger. Divide the price by the quantity — per item, per 100g, per litre, per wash — before deciding. It's surprisingly common for a "value" bundle to cost more per unit than the single item on its own promotion.
5. Add it all up afterwards
After the sales, total what you spent and what you saved. If the "savings" figure is mostly on things you wouldn't have bought otherwise, that's worth knowing before the January sales start.
Watch delivery and returns too
A £5 saving disappears quickly if delivery costs £4.99 or returns are charged. Check the free delivery threshold, the returns window and whether returns are free before buying anything you might send back. Many retailers extend their returns period over Christmas, which makes early Black Friday purchases less risky for gifts.
A simple Black Friday rule
Make a list before the sales start, note current prices, and only buy from the list. Every deal you check against these five steps is one less impulse purchase dressed up as a saving.
The calculators mentioned are free on PrimeVoucher, a UK voucher codes and deals site.
