What is Frequency Capping?

Frequency capping limits how many times one user (or one device / cookie) may see an ad, campaign, or creative in a chosen window. The unit is usually an impression: “no more than 3 serves per day,” “no more than 10 in 7 days.” Without a cap, one person on retargeting or cheap display can collect dozens of contacts: CTR falls, CPM still “delivers reach,” and post-click CR plus audience irritation do not. A cap does not change the billing model by itself: on CPM it cuts paid serves per user; on CPC it cuts how often the creative is eligible to earn a click.

What gets limited

  • Impression cap — a ceiling on serves per user / cookie / device ID per day, week, or month.
  • Creative / ad set cap — a limit on one banner so rotation does not stick on a single asset.
  • Conversion exclusions — not a cap in the narrow sense, but the same class of rule: stop showing the offer to people who already bought or left a lead.
  • Audience time-to-live in retargeting (7 / 14 / 30 days) — how long someone stays on the list; the cap decides how often to bother them inside that window.

Reach and frequency are linked: frequency = impressions / reach. A report of “frequency 8” on an uncapped campaign means the average user saw the creative eight times. That is not the same as a hard cap in settings: the metric describes what happened; the cap is a rule before the auction.

Google Ads, Meta, AdMob

In Google Ads a classic impression cap exists on Display, Video, and Demand Gen (formerly Discovery): N impressions per user per day / week / month, at campaign or ad level. Search is not capped that way — the query itself limits repeats. Performance Max and App campaigns barely expose a manual ceiling: the algorithm sets frequency. On the GDN and YouTube, a cap is the main way not to burn a remarketing list. DV360 offers finer caps (line item, insertion order, cross-campaign) plus caps on viewable impressions.

In Meta Ads, frequency is first a report column (impressions / reach). A hard ceiling like Google Display exists on Reach & Frequency (reserved buying; not every account or GEO). In the regular auction the buyer steers indirectly: budget, audience, purchaser exclusions, creative rotation, sometimes CBO. Advantage+ takes even more control: frequency climbs when the seed is narrow and the budget is large. Frequency 4+ on cold interest and 12+ on retargeting are different signals; the second more often means “the list is exhausted,” not “someone forgot the cap.”

In AdMob the cap sits on the publisher side: ad unit settings set a max number of serves per user per period so a banner or interstitial does not fire on every screen. Mediation (AdMob Mediation, LevelPlay, and others) adds network-level caps. For a UA buyer who purchases that inventory through Google App campaigns / DV360, the publisher cap shows up as lower fill and higher eCPM, not as a checkbox in the advertiser UI.

Why caps matter in performance and arbitrage

Ad fatigue: after N contacts, CTR and CR fall and cost per conversion rises. On uncapped retargeting, warm traffic turns into “this banner follows me” — especially finance, subscriptions, and long-cycle e-commerce. On cold display a cap keeps budget from a handful of bots or one user with a dozen tabs. In the tracker that looks like high spend, a flat unique count, and falling EPC.

A cap that is too low (1/day on a broad GDN campaign) starves learning and reach: the auction never gathers stats, a CPA/ROAS bid strategy never settles. A cap that is too high equals “no cap.” A working range on display retargeting is often 3–7 impressions per user per week; in-stream video sits lower because each contact is heavier. The number depends on vertical and cycle length, not a universal rule.

Who counts as “one user”

A cap needs an identifier: cookie, mobile advertising ID, a signed-in Google/Meta profile. One person with two browsers and a phone and no login gets the cap three times — real frequency exceeds the report. ATT, ITP, and cookie opt-out on the pixel punch holes in the cap: some serves never stitch together. GDPR consent shrinks the graph further. Cross-device without a login is barely capped. In-app, the SDK sees a device; on mobile web, usually a cookie. That is why cabinet frequency and “this banner is everywhere” diverge.

Related controls

A cap does not replace negative audiences and does not fix a weak creative. Read it with reach, tracker uniques, and revenue — not as the only lever. Do not mix an ad frequency cap with an affiliate offer cap (a daily limit on conversions/leads the network will pay). The first limits ad serves; the second limits volume the network will accept.

See also: retargeting, impression, Google Ads, Meta Ads, AdMob.