Definition
Impressions count how many times your ads were shown (not unique people).
Example
If an ad is shown 3 times to the same person, that counts as 3 impressions.
How to use it
- Impressions = reach * frequency (approximately, within a time window).
- Use impressions with CPM to estimate spend: spend ~ impressions/1000 * CPM.
- Monitor impressions by placement to detect low-quality inventory.
Common mistakes
- Assuming impressions equal unique users (reach is the unique metric).
- Optimizing for impressions without checking CTR, CVR, or profit.
Why this matters
This term matters because it affects how you interpret performance and make budget decisions. If you use inconsistent definitions or windows, ROAS/CPA can look "better" while profit gets worse.
Practical checklist
- Write a 1-line definition for "Impressions" that your team will use consistently.
- Keep the time window consistent (weekly/monthly/quarterly) when comparing trends.
- Segment results (channel/plan/cohort) before drawing big conclusions from blended averages.
- Sanity-check with a related calculator from the same category on MetricKit.
- Read the related guide (e.g., Frequency and creative fatigue: diagnose performance decay and fix it) for context and common pitfalls.
Where to use this on MetricKit
Calculators
- Break-even CPM Calculator: Compute break-even and target CPM from CTR, CVR, AOV, and contribution margin assumptions.
- Break-even CTR Calculator: Compute the CTR required to break even (and hit a target) given CPM, CVR, AOV, and contribution margin.
- A/B Test Sample Size Calculator: Estimate sample size per variant for a conversion rate A/B test given baseline CVR, MDE, significance, and power.
- CPL to CAC Calculator: Convert cost per lead (CPL) into CAC using lead-to-customer rate (and compute targets).
- Break-even CVR Calculator: Compute the CVR required to break even (and hit a target) given CPM, CTR, AOV, and contribution margin.
Guides
- Frequency and creative fatigue: diagnose performance decay and fix it: Learn how frequency, reach, and impressions interact with CTR/CVR, when to cap frequency, and how to refresh creatives without tanking learning.