On Black Friday, advertising costs almost twice as much. It also returns far more.

Every year in late November, the price of online advertising takes off. On Meta, showing an ad to a thousand people costs almost twice as much on Black Friday as it did a month earlier.

You might assume this is the worst possible time to buy ads. For four days, the opposite is true. Each euro spent returns far more than it did in October.

Then comes Tuesday. In a single day, what advertising returns falls back to its October level. The price stays 42 to 55% higher.

To see whether this story holds from one year to the next, I went back through the last three Black Fridays across the e-commerce accounts tracked in Nanga, around thirty brands per period. Each brand is compared with itself, against its late-October week, five weeks before Black Friday, and I look at the median, so that one very large advertiser can't skew the picture. Where I give a range, it runs from the lowest year to the highest.

Two industry terms come up from here on. CPM is the price of a thousand impressions. ROAS is what one euro of advertising brings back.

Four days, then it stops on Tuesday

On Friday, Meta ROAS runs 95 to 131% above October. The weekend holds up very well, +81 to +106% on Sunday. Monday is still good, +52 to +69%.

On Tuesday, the same measure lands between -28 and +24%, depending on the year. Nothing warns you, and CPM has only come down a few points. A brand that keeps Monday's budget is still paying a lot for an ordinary return.

Google follows the same path with less drama: +26 to +80% on Friday, -12 to +11% on Tuesday.

The week after holds up

The following week is no disaster. Meta ROAS stays 15 to 31% above October.

I wanted to know whether cutting the budget protects returns. Brands that cut lose less than those that keep raising spend, but the same gap already exists in September and October. So I can't attribute it to Black Friday.

You start paying before the peak

Prices don't wait for Friday. In the week of 16 November, Meta CPM is already up 26 to 39%, and budgets are up 29 to 41%. From 16 to 18 November, ROAS goes nowhere: -5 to +10% across the three days combined.

Some of that money may be preparing Black Friday, by getting a brand or an offer known ahead of the day. These figures can't measure that. On Google, the same week looks much better: ROAS gains 20 to 23%, three years running.

December, the part people forget

Once Black Friday has passed, it's easy to feel the season is over. Yet from 7 to 20 December, Meta ROAS stays 9 to 68% above October while CPM eases down.

Not everyone benefits equally. From 14 to 20 December, fashion gains 48 to 96%, while beauty and care brands range from -11 to +15%. These groups are small, about ten brands each, so treat it as an order of magnitude, though a hard one to ignore.

On 21 December it's over on Meta, -5 to +7% through the 24th, perhaps because it's getting too late for delivery. Google holds up better, +5 to +10%, with CPM already below its October level. And just after Christmas, on Meta, advertising costs 9 to 20% less than in October and returns 8 to 23% more.

If you don't sell online

For brands chasing leads rather than sales, Black Friday looks mostly like a bill. On Meta, the cost of a lead rises 18 to 41% that week, and is back to -2 to +19% the week after. Shifting what can be shifted is worth thinking about. On Google, nothing clear: -1 to +14%. These measures rest on fewer accounts, between 7 and 24 per year.

What these figures don't say

ROAS comes from the ad platforms, and they know nothing about your margin. A doubled ROAS at 30% off is not the same as a doubled ROAS at full price.

ROAS is also more fragile than CPM. With around thirty brands, changing the reference week can move a figure by several dozen points. The direction holds, the size doesn't.

These are also observations over three years, not laws. And nobody is the median brand. If your CPM runs well above these numbers, look at your account before blaming the market.

And this year?

In early November, CPM is up about 5% on both Meta and Google, nothing unusual so far. If this year follows the path of previous ones, Black Friday week should land around +60% on Meta, +43 to +79%, and +34% on Google, +20 to +49%. Three weeks before Black Friday, the method has been off by about 12 points on average in past years.

The answer comes at the end of November.

The detail, week by week

For anyone with a budget to allocate, here are all the benchmarks, against the late-October week. Dates follow the 2026 calendar; up to 6 December, past years are aligned on Black Friday.

Meta

Google