How to Tell If a Black Friday Deal Is Actually a Deal

Black Friday 2026 lands on Friday, November 27 — the day after Thanksgiving — and “early Black Friday” prices are already creeping into stores and inboxes. Some of those deals are genuinely the year’s lowest prices. Others are theater: a price raised in October, then “cut” in November.

You don’t need a finance degree to tell the difference. You need five quick checks and the same percentage math this site’s calculators run. Here’s the full playbook.

Quick answer: A real Black Friday deal survives five checks: (1) compute the true discount as (original − sale) ÷ original × 100 and compare it to the advertised percentage; (2) verify the “was” price against a price-history tracker; (3) run per-unit math on bundles; (4) remember stacked discounts multiply, they don’t add; (5) compare against the item’s October price, not its November sticker. If a deal fails two or more checks, walk away.

Check 1: Recompute the advertised discount yourself

Retailers sometimes round up — or just fib. Take the original price, subtract the sale price, divide by the original price, and multiply by 100. That is the real discount.

Example. A TV listed at $799, “was $1,099,” advertised as “30% off”:
($1,099 − $799) ÷ $1,099 × 100 = 300 ÷ 1,099 × 100 = 27.3%

Not 30%. A 2.7-point gap on an $800 purchase is real money — and if the advertised percentage doesn’t match your math, that’s a signal about how the store treats the other four checks too.

Check 2: Interrogate the “was” price

The oldest trick in the sale playbook is inflating the reference price. A jacket “was $250, now $149” is only 40% off if the jacket actually sold at $250. Consumer-protection agencies have repeatedly warned retailers about this: the “was” price has to be a genuine recent selling price, not a number invented for November.

Your move: paste the product into a price-history tracker (camelcamelcamel for Amazon items, Google Shopping’s price history for everything else) and look at what the item sold for in September and October. If the “was” price never existed, the “discount” is fiction.

Check 3: Do the per-unit math on bundles

“Bigger pack, bigger savings” isn’t automatic. Divide the price by the number of units and compare per unit across sizes.

Example. Coffee pods: 48-pack for $35.99 vs. 24-pack for $19.99.
48-pack: $35.99 ÷ 48 = $0.75 per pod. 24-pack: $19.99 ÷ 24 = $0.83 per pod.
The big pack genuinely wins here — but run it every time, because clearance “value packs” frequently price worse per unit than the regular size.

Check 4: Stacked discounts multiply — they don’t add

This is the single most misunderstood piece of sale math. “Extra 20% off already-reduced prices” does NOT stack additively with the first discount.

Example. A $200 jacket, 30% off, with an extra 20% taken at checkout:
After first discount: $200 × 0.70 = $140. After second: $140 × 0.80 = $112.
Total paid: $112. Real total discount: ($200 − $112) ÷ $200 × 100 = 44% — not 50%.

The general rule: multiply the keep-rates. 0.70 × 0.80 = 0.56, so you keep 56% and save 44%. Retailers know most shoppers do the lazy addition in their heads. Now you won’t.

For the quick mental versions of these tricks, see our discount mental math tricks guide.

Check 5: Compare to October, not to the sticker

Adobe’s holiday forecast projects $275.1 billion in U.S. online sales from November 1 to December 31, 2026 — and retailers begin discounting well ahead of the post-Thanksgiving rush. That early window is exactly when “was” prices get massaged upward.

So the comparison that matters isn’t sale price vs. sticker price — it’s sale price vs. what the item cost in early October. If you were already eyeing something, screenshot or bookmark its price now. That October number is your personal baseline, and no marketing department can revise it.

The Deal-Truth Scorecard (run this on every big purchase)

Give each deal a pass/fail on the five checks above:

#	Check	Pass looks like
1	Discount math	Your recomputed % matches the advertised %
2	Was-price check	Price history confirms the original price was real
3	Per-unit math	Bundle genuinely beats smaller sizes per unit
4	Stacked discounts	You computed the multiplied total, not the added one
5	October baseline	Sale price beats the early-October price

Rule of thumb: 5 passes = buy with confidence. 4 passes = good deal, minor fudge. 3 or fewer = the “deal” is mostly marketing — wait for Cyber Monday or December clearance instead.

FAQ

Key takeaways

• Recompute every advertised discount: (original − sale) ÷ original × 100. Trust your math, not the sticker.
• Verify “was” prices against a price-history tracker before believing any percentage.
• Stacked discounts multiply (0.7 × 0.8 = 44% off), they don’t add (not 50%).
• Your October screenshot is the only baseline that matters — compare the sale price to it, not the November sticker.
• Run the 5-check Deal-Truth Scorecard on anything over $100; three fails means walk away.

Want the numbers done for you? Run any price pair through the percentage calculator on percentiva.com.