Reach and impressions: what is the difference
Also known as: reach, impressions, unique reach
Reach is the number of different people who saw an ad or piece of content; impressions is the number of times it was shown, counting repeats. If 1,000 people saw an ad three times each, reach is 1,000 and impressions are 3,000. Dividing impressions by reach gives average frequency: how many times, on average, each person saw it.
Average frequency = impressions ÷ reach
With 3,000 impressions and a reach of 1,000 people, average frequency is 3. Reach is always less than or equal to impressions.
A restaurant's launch campaign got 60,000 impressions in a month. It sounds like a lot, but reach was 6,000 people: each saw the ad ten times on average.
For a launch, the goal was to be seen by many new people. The team caps frequency and widens the audience; the next month, with the same budget, reach tops 20,000 people.
The difference in practice
| Answers | Counts repeats? | |
|---|---|---|
| Reach | How many people saw it? | No; each person counts once |
| Impressions | How many times was it shown? | Yes; every showing counts |
| Frequency | How many times did each person see it, on average? | It is the ratio between the two |
How Google counts
In Google Ads, an impression is counted each time the ad is shown on a search results page or another site on the Google Network. In some cases only part of the ad is shown, and the impression still counts.
Reach is harder to measure, because the same person uses several devices. Google estimates the number of unique users, not cookies, who saw the ad, deduplicating across sessions, formats, networks and devices with statistical models, and only reports data once a minimum number of people is reached.
When to look at each
- Brand and launch campaigns: reach and frequency tell how many new people met the brand and how often they were reminded.
- Conversion campaigns: impressions matter as the base for other metrics, such as CTR and CPM.
- Organic content: reach shows distribution; high impressions with low reach mean the same audience seeing it repeatedly.
An impression is not attention
A recorded impression means the ad was shown, not that anyone paid attention. Fast scrolling, an ad in the corner of the screen and partial display count the same. That is why impressions alone say little about results; they make sense alongside clicks, completed views and conversions.
Common mistakes
- Calling impressions people reached in reports.
- Adding up reach across campaigns: the same person may have been reached by both.
- Ignoring frequency and wearing out the same audience with the same ad.
- Using reach as the goal of a campaign that should generate sales.
Frequently asked questions
What is the difference between reach and impressions?
Reach is the number of different people who saw the content. Impressions is the number of times it was shown, including repeats to the same person.
How do you calculate frequency?
Divide impressions by reach. With 3,000 impressions and 1,000 people reached, average frequency is 3.
Can reach be higher than impressions?
No. Every person reached saw the content at least once, so impressions are always equal to or greater than reach.
Can I add up reach from two campaigns?
Not safely. The same person may have seen both, and the sum would count them twice. Deduplicated reach reports solve this.
Does an impression mean someone saw the ad?
It means the ad was shown. It does not guarantee attention, so impressions need to be read together with clicks and conversions.
Related terms
- CPMCPM (cost per mille, or cost per thousand impressions) is what it costs to show an ad a thousand times...
- Engagement rateEngagement is the measure of how much people interact with content or a website: likes, comments, shares...
- CTRCTR (clickthrough rate) is the percentage of people who clicked after seeing an ad, an email or a search...
- Paid trafficPaid traffic is the visits that reach a website, page or profile through ads: on Google, YouTube, Instagram...
Rodrigo Fávaro
Founder of ROO3, a marketing and technology agency in São José do Rio Preto, Brazil. Builds AI products running in production (Tobia, gerar.app, Pense Mercado) and maintains the AI Benchmark, a public ranking of AI models.
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