Ad Frequency
Also known as: frequency, ad-frequency
The average number of times a single user sees your ad within a given time period.
Frequency is the metric that decides whether more spend translates to more reach or just more repetition. On Meta and TikTok specifically, it's the biggest under-managed lever in performance accounts — teams watch CPA and ROAS but ignore frequency until CPMs have already spiked.
Definition
Ad frequency is the average number of times each unique user has seen an ad during a campaign, calculated as impressions divided by reach.
Why it matters
Frequency directly shapes cost per result and creative wear-out. Too low and the message doesn't land; too high and CTR collapses while CPMs rise from ad fatigue.
Formula
Frequency = Impressions ÷ Reach
Typical CTR decay by frequency in a mid-funnel Meta ad set.
How it works
- —Platforms count every impression, then divide by unique reach.
- —Frequency accumulates over the campaign's active window.
- —Optimal frequency depends on funnel stage: prospecting 1–3, retargeting 4–8.
How frequency compounds
Frequency accumulates over a rolling window (usually 7 or 28 days). A campaign hitting the same custom audience weekly reaches frequency 5–6 by week four — often with declining CTR and rising CPM because the algorithm has to reach harder into the audience to find people who haven't seen the ad.
The right frequency by funnel stage
Cold prospecting: 1–3 in a 7-day window is healthy. Higher and you're paying to repeat before you've reached the wider audience. Warm retargeting: 3–5 is a reasonable ceiling. Hot retargeting (cart, checkout): 6–8 in a 7-day window is fine; these users have shown clear intent.
How to keep frequency in check
(1) Set frequency caps per ad set (Meta: Reach & Awareness objectives; TikTok: at campaign level). (2) Refresh creative weekly for high-frequency audiences. (3) Exclude recent buyers from prospecting. (4) Use creative refresh rate as a leading indicator: shipping one new asset a week per audience keeps fatigue manageable.
A campaign with 90,000 impressions and 30,000 reach has a frequency of 3.0 — the average user saw the ad three times.
Common mistakes
- ✕Ignoring frequency until CPA spikes.
- ✕Treating one global cap as the right answer for every audience.
- ✕Refreshing budget instead of the creative.