whatiscpm.com

Worked scenario

Reach vs frequency at a fixed budget

By Oliver Wakefield-Smith · updated July 2026

The short answer

The site's second formula: impressions equal reach times frequency. A $5,000budget at Meta's sourced $13.48 average buys about 370,920 impressions no matter what; frequency decides whether that is 370,920 people once or 74,184 people five times.

impressions = reach × frequency

$5,000 ÷ $13.48 × 1,000 = 370,920 impressions to allocate

Rate: Gupta Media Meta global average, retrieved July 2026.

Frequency capNet reach (people)Reads as
1x370,920maximum breadth, zero reinforcement
2x185,460the conventional awareness zone
3x123,640the conventional awareness zone
5x74,184reinforcement, at a real cost in people
8x46,365saturation territory; check for fatigue

Neither platform publishes an optimal frequency; the effective number depends on creative, category and cycle length. What is documented: both major platforms ship frequency caps as a control because uncapped delivery drifts toward cheap repeat impressions, and repeat impressions past attention are where budgets go to die quietly.

Fixed-CPM buyingR&FMeta reach and frequency buying: fixed CPM quoted upfront with frequency controlsMeta reach and frequency buying, Meta Business Helpretrieved July 2026
Frequency capscapFrequency capping limits how many times one person sees your display or video adGoogle Ads frequency cappingretrieved July 2026

When paying a fixed CPM for reach beats the auction

Meta's reach and frequency buying quotes a locked CPM upfront in exchange for committing budget, with frequency controls built in. You typically pay some premium over the auction's cheapest path; what you buy is predictability, which matters for launches and date-bound campaigns where under-delivery is worse than overpaying slightly per thousand. For always-on performance spend, the auction usually wins.

Frequency saturation is cause three at why is my CPM so high. The budget side of this trade is worked in the $1,000 test budget, the base formula at /formula, and your own numbers go in the calculator.