Meta's peak-season guide: ad sets under about 50 conversions a week cost about 28% more per purchase, plus a formula for how many ad sets your budget can feed
What changed
In "Peak Season 2026: You Don't Beat The Auction. You Brief It." (Meta for Business, Oct 21), Meta says ad sets getting fewer than roughly 50 conversions a week ran about 28% more expensive per purchase in its own analysis. It gives a ceiling for ad set count: weekly budget divided by (cost per result x 50). It asks advertisers to settle three choices (what to optimize for, how to bid, how results are counted), batch edits so one learning phase replaces several, and hold the largest campaign still while an A/B test or Conversion Lift study measures it. Meta doesn't publish the method or sample behind the 28%, so treat it as Meta's directional guidance, not a benchmark.
What to do
Run the formula on your account: at a $40 cost per purchase, a $20,000 weekly budget feeds about 10 ad sets. If you're over that, consolidate before Black Friday, batch any setting changes into one edit, and leave your biggest campaign alone through peak with a lift or A/B test running.
Source
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