The honest answer to this question is: it mostly doesn't matter anymore. But there are still some real differences worth knowing, and there's one genuinely better strategy than chasing either day specifically.
They've Merged Into One Long Event
Cyber Monday as a distinct event made sense in 2005, when a meaningful portion of the population only had high-speed internet at work, and the Monday after Thanksgiving was when people got back to their desks and shopped online. That's not the world we live in. Everyone shops online all the time, and "Cyber Monday" is now just the end of a three-to-four week sale period that starts in late October or early November.
Major retailers have responded by extending deals across the entire period -- "Black Friday prices all week" and "Cyber Week" language has replaced single-day emphasis. If you see a deal on Black Friday that you want, you don't need to wait for Cyber Monday. Conversely, if you miss something on Black Friday, it'll likely be available at the same price or close to it through the end of the week.
Where Black Friday Still Holds an Edge
TVs and large appliances: In-store traffic and competition among big-box retailers drives some aggressive pricing on these categories specifically on Black Friday. Doorbuster-style TV deals, while less common than they used to be, still tend to cluster around the Friday-Saturday window.
In-store experiences: If you want to see a product before buying -- feel a mattress, test a laptop keyboard -- the in-store sale activity peaks on Black Friday weekend. Some deals are still in-store-only or have better in-store inventory during that window.
Where Cyber Monday Has the Edge
Software and digital products: Apps, subscriptions, and digital services tend to run their biggest discounts around Cyber Monday specifically, because they can serve unlimited demand and don't need the in-store logistics of Black Friday.
Smaller electronics and accessories: Cables, phone cases, smart home gadgets, and accessories often see their deepest discounts later in the sale week.
If you missed out on a deal: Monday and Tuesday tend to bring "second wave" deals that include items that sold out earlier in the weekend.
Data on Price Differences
Price-tracking analysis done by consumer research firms year over year consistently shows that the average price difference between the best Black Friday price and the best Cyber Monday price for the same item is within 2-3%. Some items are cheaper on Friday; some are cheaper on Monday. Across a broad basket of products, they're essentially equivalent.
The bigger finding from that data is that the "deals" around both events are sometimes not the lowest prices of the year at all -- some items hit lower prices in October or January. This is why a price tracker is the only tool that answers the question definitively for any specific item.
The Better Strategy
Don't organize your shopping around Black Friday or Cyber Monday as events. Instead: make a list of the things you actually want to buy before November, set price alerts on those specific items, and buy whenever the price hits the target you've decided on ahead of time.
With price alerts running through October and November, you'll catch the real lows regardless of which "day" they fall on. Some of those lows will be on Black Friday. Some will be on Cyber Monday. Some will be on a random Tuesday the week after. The alert doesn't care about the marketing calendar.
The shopping calendar of Black Friday and Cyber Monday is a retailer invention that's useful for them because it concentrates purchasing decisions. For shoppers, the better frame is "extended sale period" and "buy when the price is right," not "which single day should I prioritize."